Uh oh...picked up a Turbo Seca

Thanks for that. I probable have to glue the spigot back in to the surge tank. Would a simple epoxy work?

There is a mess of hoses, and it's not very clear in the manual. As for the hose that goes from the carb boot to the pressure sensor, do you mean it goes off the carb? Because all four of my manifolds had caps, but there is a spigot off the number 2 carb that I had no idea what it connected to.

And I did test the pressure sensor. I think it output 2.1V with a 12.something V battery, so it's good (always nice to pass those tests )

 

I took my time and paid somewhere around 30-45 bucks delivered for my pump. The older ones work fine too. The only reason they are "in-tank" type is to save space on the R6.

I really can't comment on the other type of controller but I'm all in favor of you trying it! Heck, I just returned from a 1000 mile round trip that confirmed that I very sucessfully retro-fitted my Vstrom 1000 with a BMW shock and it works perfectly....$102.60 for a low mileage shock(and case hardened longer bolt) vs. $1000 for a new Wilbur.....You'll never hear me tell you "that won't work"....but let us know how it goes.

You have to understand my goal when I built my bike....originally I was only building it to sell so productivity mattered more than thought. The system I installed works well, better than most and it allows a degree of adjustability most don't have. With two other bikes needing engines built, that was good enough for me and I'm still happy with it but it doesn't mean I don't think there are other, maybe even better ways to accomplish the same goal of fantastic boost without turbo stall. That would be your enemy.....and very, very hard on the turbo. It's what you got with the "powerup kit"....forced stall every time the bov activated!

Good luck!

jeff

 

T the line before the controller for your pressure gauge tap.

Other than that I don't think I'll be of much help on a turbo bike. My turbo vehicle is much larger and it doesn't need a BOV.

 

From what I understand (from doing a bunch of reading on turbos today) is that using the pop-off valve to control boost doesn't stall the compressor.

Compressor stall happens when the intake after the compressor gets charged to a point where the compressor can't move any more air. This happens when you close the throttle, the compressor need a certain mass flow to keep compressing incoming air.BOV vents that pressure, increasing mass flow and prevents stall.

Also, I think the wastegate still actuates with the power up kit. I think it just reduces the signal to the wastegate, much like the MBC do. It just isn't adjustable.

I have seen other advice on increasing boost for turbo secas that involves capping off the waste gate actuator and using the BOV for boost control. And THAT seems to be detrimental because it'll allow the turbo to over-spool.

Actuating the waste gate actually reduces shaft speed and the amount of work being transmitted from the turbine to the compressor. Actuating the BOV doesn't reduce the work being transmitted from the turbine to the compressor, it only wastes it after the compressor.

That being said, I think I'm going to try the ball and spring MBC, with a T for the gauge, and get rid of the power up kit. All I need to figure out now is the fuel pump.

^^^Please, anyone correct my understanding if I'm wrong^^^

 

Well Houston...we have a problem. As usual, I get ahead of myself, and get knocked right back down to reality.

I spent all evening trying to set my float height to no avail. The float valves ended up leaking. I'm still praying that I get off without having to replace these, but more than likely, chacal will be hearing from be soon. EDIT: I found this: http://www.carbkitscapital.com/carb_kit ... odel=XJ650 and this: http://www.bdesigns.ca/Yamaha_Carb_Kits.htm . I ordered some exhaust gaskets from BDesigns.
For less than chacal sells one, I can get all four, maybe it's worth trying.

It looks like the valves aren't seating right when first filling up the bowls. The fuel level way overshoots, and starts leaking. I shut off the valve in my test tank, and keep checking the fuel level (draining what's over the valve setting) until I get a consistent reading, then open the fuel valve on the tank, and alas, no leaking.

I've sanded down the sides of the needle valve and the bore with 1000 grit paper, hoping to clean off some corrosion and varnish. It seems to have helped, as now only #1 leaks like a sieve (started out 1,2,3) when I first fill the bowls. But it seems like once the valve seats, it stops leaking all together. Obviously, if I can't get them all to perform consistently, I've got to replace the fuel valve assembly.

On a related note, from where am I measuring to when measuring the fuel height? I don't know if it's Mikuni's, or just the Turbo Seca carbs, but the edge of the carb body that faces the float bowl is not flat. It's raised on the back corners, and raised even more on the sides. So what am I supposed to measure the 2mm spec from?

 

FWIW I bought my carb kits from Brian at bdesigns and got the super-duper kits....forget what he called it but it had all the o-rings for the fuel system....and was by far less expensive then anywhere else....not knocking any vendor, just sayin. Proofs in the pudding....no runs, leaks or errors and I run a bit more boost then most.

jeff

 

No I know. I wish I had found his website before ordering my carb parts from chacal, but it's too late now. I still think len's prices are reasonable, but Bdesigns parts are a steal.

 

Does anyone know what to measure the 2mm float height spec on the Turbo Seca Carbs? I'm having the same issue as this guy: http://xjbikes.com/Forums/viewtopic/t=2 ... eight.html

(Second image). The bottom of the carb body has thee different "levels", 2 in the back, and a lower one on the side.

 

So after much frustration trying to set the float heights, even with new float valves, I put this project aside for about a month.

I realized that there was no way that the 2mm spec should be from the carb body on the back, but from the side, because that's how you'd measure is on the bike. So I did that and set miy fuel levels...finally, about 2 weeks ago.

I started assembling everything. Mostly went well except for having to remove the carbs to install the little throttle cable :x . And spending 1.5 hours looking for a nut to the starter that dropped into the turbo/exhaust mess, then promptly hid out of sight. I really need to figure out how to train the mice in my garage to find lost parts like that

So the bike is just about to start. I need to put oil in and fill the tank, that's it. Maybe I'll give it a shot today. I checked each of the fuel system components, and they all appear to work, but I've just got this "vision" of the pressure regulator not working, and the fuel pump just pumping my crankcase full of gas. We'll see.

Finally, I've got my work cut out for me on the plastics. I need to some repair on the tail fairing, as two of the tabs are broken. I also need to repair the lower scoop, as it looks like both sides have been repaired, and the little scoop at the bottom doesn't fit (and there's no hole in the repaired pieces for the bolt/nut. Going to use fiberglass repair with some glas mat, unless anyone has any objections/suggestions. I also need to glue the trim on the windshield. What's best for that?

Does any one have any suggestions on rubber repair or parts sourcing for the mirror covers and clutch lever. These are in really bad shape, and I'd love to clean these up too.

Finally, I found that I'm missing ONE FREAKING FAIRING STAY for the the left fairing that goes over the tank. I don't think it's ever been on the bike since I got it (the fairings weren't installed when I bought it), so now I'm on the hunt for that part.

 

SUCCESS!!!!! well sort of successful... IT STARTED!!!! but it poured gas out of the carbs and wouldn't stay running :cry:

So I knew I wouldn't have time to tune it tonight, so I just wanted to see if it would run. It started with full choke, and started to run, but then the idle picked up a little too much and I shut if off. Then I couldn't get it started again. I was monitoring the airbox drain hose and saw nothing, but finally noticed some gas running down the side of my (newly painted!) engine. I cleaned it up, and checked the fuel level in the carbs (I'd wet set the float height weeks ago...that was a painful process), and all were over full.

I drained a bunch of gas (93 octane no less) from each of the bowls, then decided that I'm not out yet. I pulled each of the plugs just to dry them off a bit (definitely gas in every cylinder). Choke off, it started, ran, and idled JUST FINE! It's just bench synced, and the pilot screws are all 2.5 turns out (i think) but it idled like it's been tuned already.

Now I know I've got a little gas in my (freshly changed) oil, but it's not much. Not only is my petcock rebuilt, but without a fuel pump to feed gas to the carbs, they can't overflow by much when it's not running or turning over. I figure I can run it like this for tuning and up and down the road and I'll change the oil again before really putting it into service.

So why the leaky floats? Well I knew I should have assembled the whole fuel system off of the bike just to make sure there was no overflow, but it just seemed too difficult. Since it ran great the second time, and I wet set the float height 2 or 3 weeks ago, I'm hoping that the floats were all just a little dry and needed to be wet and actuated a bit. Either that or the regulator isn't behaving, and the pressure behind the check valve is higher than the 2psi is should be. I checked the regulator alone by putting an air hose to is with a slight pressure and seeing if it would open, then increasing the pressue until it did. But since the pressures we are talking about are low (2psi) I couldn't measure it. I'll have to check the fuel height the next time I run it to see if everything is behaving or if I need to dive back in (I was so happy to be past that :roll: )

Anyway, one other small problem. The tach is REALLY SLOW....When I rev, it just climbs really slowly. It'll eventually get there, it just takes a long time. Do I need to lube the tach? Will it get better on it's own (I think I know the answer to that :twisted: )

 

Either that, or your tach spring got stronger instead of weaker over time.

This is such a fun thread to read. I can't wait until you make this thing scream.

 

I read of a guy using a Suzuki remote hydraulic shock adjuster to adjust boost on his turbo set up by using it to increase or decease the preload on the blow off mechanism.

 

Thanks for the encouragement fintip, I was starting to think no one was following (I know I haven't posted many pictures, but my garage is so cramped/cluttered/poorly lit).

Well I've solved two problems over the last two days, but confirmed another two:

One, my headlight wasn't coming on. I assumed that there was a headlight relay somewhere like my 750 seca, and that I'd have to troubleshoot that, but then I inspected the wiring diagram and found no such thing. No 12V at the plug (although oddly, either high or low beam did have 4V). I traced the circuit all the way back the the first connector after the fuse. Had 12V at both sides of the fuse, nothing at the connector, and according to the wiring diagram, there was NOTHING, not even a splice, between the fuse and connector.

Then I remember that there were a couple of wires that had no connector (they were part of some alarm, basically an electronic box and a bell). I had capped and taped them off, as I didn't feel like digging into the harness to find what they went to. Well guess what, one wire had 12V, and the other had connectivity with the plug! Sure enough, connect the two together, and all my dash lights and headlights worked! Since I've got a proper crimping tool and a set of terminals, I put a couple of bullet terminals on that thing and called it a day. I have no idea why an alarm would be in the middle of the headlight circuit. I'd think you'd want to disable the ignition circuit, it's not too hard to run away without the headlight circuit. Heck, anyone who steals a motorcycle doesn't bother hot wiring it anyway, lift it and away they go.

And I fixed my tach. I took a bunch of pics in case I decided to put together a How-To, but in the end, I really didn't know what I was doing, and it's basically just carefully remove screws, carefully replace screws. I tried to follow BigFitz52's write-up on 550 seca gauges to get a feel for what I was lubricating. I sprayed some cabe lube in the areas that he mentions in his write-up, I figured it fit the bill: It says it cleans (so there is a solvent involved) and when it dries it leaves a dry lubricant in it's place. Working the needle around, there was an obvious drag under "2000 rpm". It didn't go away immediately. I just kept playing with the needle. Then I moved on to the speedo and lubed it the same way. After letting them sit for a few minutes, I played with the needles again, and low and behold, there wasn't any drag at lower "rpms" or speed, the needle returned quickly.

One more note on gauges, my turbo seca only has 6000 miles on it, and has been in basements and garages it's whole life. There is NO fade on the gauges, it was amazing looking at them when they were apart. But I noticed some finger print smudges from handling them. No problem I decided, I'll just use a little rubbing alcohol to clean that up. BIG MISTAKE! It started taking paint off and left a dry looking trail! My heart sunk. I decided to rub some di-electric grease on and buff it out to get the shine back, and it seemed to work, but that was a bummer.

So now that I "think" the gauges will work, I hurriedly assemble them and install them on the bike. It's 11 pm, but I decide that it's worth it to quickly start it and see if the needle responds. I put it on RES (there's no a lot of gas in the tank) and it fires right up. Last week, I had messed with the idle and set it way too high, but it revved right up and the needle followed along. Another success!

So this morning, I decided to ride my Seca into work, and I smell gas. I left the petcock on RES, and gas has overflowed (again). Looking closely, I noticed that just like when I first started it, gas didn't come out of the overflow, it came out of the carbs, and this time in particular, #3 carb boot was wet. All of the rubber on the intake side is a little "short" so I think it'll behoove me to pull it all off again (although getting those carbs back on is a nightmare). I'll probably try "boiling" all of the intake rubber hoping for some swell and pliability, and I'll have to take another look at setting the float height. I've already replaced all of the float valves with a set from BDesigns, which another member on this forum had an excellend experience, so I'm hoping that just I loosened some crud when cleaning the fuel system and it got lodged in there.

One a positive note, the duplicolor engine paint (which dried months ago) seems to actually be gas resistant, it's not peeling off or dissolving.

Once I get this sorted out, it's just sync/pilot mixture tuning, installing the boost gauge, and some plastic repair, and I'll be ready to ride!

 

I'm following but have nothing really constructive to add.

 

i don't know if this helps but something to consider.
the K100 spec is "about"36 psi with a relief valve at 68 psi
http://www.mychamp.com/K100/3/index.html

NAPA (Mustang) fuel pump for K11 fuel pump

Date: Wed, 19 Nov 1997 10:08:30 -0500 (EST)
From: BillZ <BilZ@longride.net>

Mine died a sudden death somewhere around 70k (93 K11rs, not that that should make a difference) and I am now the proud owner of a NAPA pump for a 4 cyl Mustang, $80 and doing fine.

Date: Fri, 20 Feb 1998 21:31:47 EST
From: BilZ@longride.net

If you want to add to the fuel pump reference of mine, the NAPA part # is P74095 for the pump I installed. The NAPA pump now has over 30k on it with no problems.

 

So I spent the day trying to repair the chin fairing plastic. I'm having trouble fitting the three pieces together, because the two side pieces have been repaired before, and look like they'd never been fitting (because they are missing any holes for screws. So I'm working on removing material from the inside and reinforcing the bolt holes. I still haven't figured out exactly how well those two pieces fit together.

I also just realized that there is yet another piece missing from the bike, the seat latch that goes into the lock. Does anyone know if it's the same as any other model?

Also, I can't really get the seat on right. Does the tab in the front rest on top of the tank, or slide underneath? Does the seat slide forward then downward to install? The rear latch always seems to get caught on the plastic too. Very frustrating.

I also just found out something new about the history of my bike. It was last registered until at least '92...I never checked the document holder under the seat

 

Ok, so I figured out that the tab on the seat pan goes underneath the tank. It looks like part of the pan contacts the inner fender, and it won't go down all the way. There's about a half inch gap between the back of the tail fairing and seat when everything latches down. So I don't know if I've got something assembled incorrectly, if something on the frame is off, or something is wrong with the seat.

I'm starting to think a hammer could make quick work of the offending spots on the pan that are making contact. Any other ideas?

Also, started it again just to hear it run. Noticed two oil leaks. One looked to be at the drain bolt, easy enough to fix on the next oil change.

I had another one, kind of soupy but definitely oil, on the left side near the lowest part of the muffler. I've read about the turbos pooling oil when you don't run them, but the fact that it pooled at the front of the muffler is a bad thing right? Means the muffler is rusted through?

How is this thing supposed to act when it's being choked? I can get it to rev to 3k rpm at "idle" with just the choke in the right spot, but it needs choke to keep idling. Obviously I'm running lean, but that sounds like an air leak right? If not, it wouldn't rev so high would it?

I'm going to take all of the intake off again when I rebuild the check valve, and boil them to make them more pliable. Hopefully re-installing everything should take care of any air leaks. I haven't synced or set the mixtures yet, but I can't get a good idle without choke to do it. How many turns out on the pilot mixture screws?

 

So I propane leak tested around the intake and didn't see any changes, so I decided to try to tune it up anyway, and see if I could set the mixtures and sync. I also leveled the bike and checked the float levels again, and all were in spec (some a little higher and lower than others, but still good.

In the end, the idle is a little lopey, and although I saw spark through the color tune, the "fire" wasn't very consistent on any cylinder (you could see a miss every couple of strokes). I read lots about coils and although they ohmed to spec, and I have an extra set, I might be in the market for those.

Hammering the seat pan seemed to help a bit, but I need to hammer some more.

The oil leak coming from the muffler is nothing to worry about. There's a weep hole in the pipe, and that's where the oil is coming from .

I'm really starting to think that I picked a bad example of a turbo seca to restore. It's only saving grace is the mileage. Even though it was nearly free ($250). I came to this realization when I turned the handlebars full right lock, and the grip contacted the tank plastics.

The guy I bought it from mention that the guy he bought it from (he hadn't actually started restoring it at all) said it had been "dropped." I naively assumed this was at low speed with little damage, but now I realize that just about every plastic has been repaired, and I think some of the fairing mounting points have been bent out of shape on the right slightly (I had particular trouble getting the right front panel around that gauges).

So now I'm in the market for a set of handlebars (though I might try to bend these back) and a seat lock. I still need to repair the chin fairing, but after that it'll be ready for the road. I might take a day off this week to register it and scrub the tires. Of course, after spending hours tuning the idle, I checked the charging system voltage and didn't like what I saw. I'm hoping that the battery was just a little weak from all that idling and was keeping the voltage low, so I fully charged the battery and I'll check again today.

Pics will be coming soon.

 

Turbo seats: '82 and '83 seats look identical, but the pans are slightly different; the bend angle of the pan (at the front end) is different between the 2 years, and the slide-under bracket at the front is different (on '82 models, it is curved, on '83 models, it is straight). The "tune-up" decal....if still present....on the rear of the pan will tell you whether it is for a 1982 or 1983 model.

 

Hey chacal thanks for that. I checked and there is a decal on the seat that describes the tune up for a 1982 seca. The slide under bracket "straight" in that it is like a "Z" bend (two right angles). And the frame is a 1982 (16G0008xx). I'm missing one rubber bit, maybe they are in the wrong places?

Anyhoo, another day, another set of problems solved, and created, and solved again:

I checked the charging system, and much so my surprise (and dismay) it went up to 15.08V (measured at the battery)! I'll have to keep an eye on this and test it further. Problem solved.

So my brother-in-law comes outside to check what I'm doing. He points out the dash, and asks what the lights that are on are for. I say no-prob, it's just that the kick stand is down (when it's on it's center stand). "See watch this," I say, then I kick it up. Light stays on. "Hmmm, that's no good, that means that if I put it in gear with the clutch in, the engine will cut out as a fail safe." I grab the clutch and put it in gear...still running. Also not good. I don't know why it's still running, but I figure that if the fail safe ever kicks back in, and the kick-stand registers as down, the bike will just cut off and won't start or run again.

So I proceed to troubleshoot. Mind you, this involves pulling ALL of the plastics off to get under the tank and find the various relays.

I test the sidestand switch first. It's a little intermittent, but after cycling it a few times, it's consistent. Still get the warning light.

I check the clutch switch (figuring that's keeping it running when in gear). It functions fine.

I check the starting cut-off relay and side stand relay, both work fine. I decide to focus on the kick stand warning light, and find it's input on the dash. Try to find the plug, but the wiring diagram says it's the only 9-pin plug in the headlight that full. Neither of the three are full, so I just go by wiring color. I find the connector, and test for continuity between the G/L wires, I get continuity. Well I was in the gauges, so I decide to pull them to see if I forgot to plug a wire in when assembling.

I can't find the connector, so I go back to the bike, and find the number (I used wiring number stickers on all the connectors when I first pulled the harness. "45" is the connector. I go back, find it, and lo-and-behold, the pin isn't in the connector! Re-pin it, put the gauges back on, and now the kick stand warning goes out when I pull it up. Problem solved.

So why is it running when I put the kickstand down and in gear? Well I realize that this isn't the Starting Circuit, that would stop the engine, it's the IGNITION circuit. So I go looking for the emergency-cut-off relay. It's under the tank. Well before I start digging in, let me study the wiring diagram a little closer and figure out how it works. Hmmm, that's odd, the only thing that triggers the emergency cut-off relay is the tip-over sensor. There's no connection to the side-stand switch OR relay.

Then it hits me, the side stand only affects the STARTING CIRCUIT, as in, the bike won't let you START with it down unless you are in neutral and the clutch is in. I thought my seca was different, so I check the wiring diagram, and it's exactly the same. I try it, and it doesn't cut out if I put it in gear with the sidestand down. The only thing you get wrt the sidestand being down when running is the idiot light! DUH!

Well while pulling all of the plastics off, I notice why the right front fairing doesn't fit next to the gauge, the mount isn't the same as the left side. So I jam a cheater bar, and it bends easily...another problem solved!

Well, I finally layered up the fiberglass on the lowers right. I just need to sand, maybe add a little more, and drill some holes, and it'll be ready to install. I don't know when I'll get to painting it, but it's not like I can't ride it ugly .

And here are some pics:

 

Looks good. By the time you're done with this the thread may contain everything someone needs to know about a turbo.

 

Well I finally registered the bike, 3+hours including the ride (it was pretty busy). Took the bike for a spin. It was obvious that I was still a little lean (off-idle was choppy, but the engine easily pulled over 3000 rpm.

Man it's a pain getting to the plugs. You've got to take everything off just to read them. I enriched all 1/4 turn (a lot I know, but I wanted to to put a stop to the off idle stumble). I also bled a little extra air from the calipers.

When I was putting the fairings back on, I looked for fuel leaking out of the check valve (I have o-rings for it but haven't installed them yet). I noticed where fuel likely leaked when the carbs overflowed the first time I started it, the third intake boot didn't seat properly, so I corrected that.

Take the bike out again. It pulled well off idle, and after a little riding, I stopped putting out a smoke screen.

I've got a boost gauge on the bike, but I never really saw any boost (maybe a slight green on the stock gauge), but I was just zipping around the local roads, haven't found any good ones to really set up and test the manual boost controller yet, and I really need to put a few miles on it to scrub the tires.

My question is, when do you see boost? I know it's at 6000+rpm, but does the engine really have to be under load (i.e. will I see it in first gear, or do I have to be going highway speeds?). I tried to take it to the redline in first, but it wasn't smooth over 6 or 7k rpm and I didn't see any boost. I guess I need to check all of the lines to see if any are leaking, anything else I should be looking for.

I rebuilt the turbo myself...hopefully that doesn't come back to bite me.

 

I think you need load and rpm to build the boost. You need the airflow to get it spooled up.

How high does your boost gauge read? If you have too far of a spread they can be slow to indicate.

JeffK would know all the answers but I haven't seen him around here lately.

 

It reads up to 30psi, so your right, it's not going to be obvious. I have a manual boost controller on it now, but I was thinking of putting the "power up kit" valve back on to make sure everything works and get "12 psi" of boost since I haven't gotten a higher pressure fuel pump, so I can't boost over that anyway.

I think I saw the needle "dance" a bit, but it wasn't easy to see, and there was a lot of traffic, so maybe I just never gave it a chance to build boost. I didn't see anything more than a slight "green" on the stock boost controller, and of course, it's usually reading blue (vacuum) because it gets it's signal from the engine side of the carb. The other boost gauge ties into the airbox signal, so it doesn't read vacuum. There might be some boost, but I didn't see much. I will admit, I am timid on the throttle, so I might not be driving it "right."

I pulled the left muffler and spun the turbo. It doesn't spin "that" easily. It'll spin with out dragging if I push on the blades, but if I try to turn it, with one finger, pushing on just the end of the shaft (i.e. really small moment arm), it seemed hard to turn. Of course, I tried that first, and got really worried, but I'm thinking that maybe it isn't turning all that smoothly? And it's not like it "free wheels" when I do spin it (though it's hard to get your finger in there to turn it).

I do know that the drain valve for the airbox has an o-ring that I need to replace (I forgot that I had one the last time I was in there. And the drain hose is cut, but I don't know if I can loose any boost that way.

I guess I'll just have to take a spin on the highway and see what develops. I guess we'll see if the DIY turbo rebuild was a waste and I'll just have to send for it to get done

 

Is the turbo pressurizing the air box? I'm not familiar with the routing on these.

On my truck the air filter feeds into the turbo then out to the intercooler pipes through the cooler and into the engine so a leak in the airbox (if it remained) wouldn't loose pressure or cause less pressure to build. But if it has a loose clamp on a intercooler boot it'll barely make any as it all leaks out.

Any intake leak after the turbo is going to bleed your boost and with the low pressures and volumes you're dealing with it wouldn't take much to bleed it off completely.

 

Well not the air box, but the "surge tank." The airflow behind the carbs is actually pressurized before it goes into the carbs.

 

Well I got boost! The reason I wasn't getting any boost before is because I'm dumb.

I put a manual boost controller on the bike, and planned on setting it to 12 psi (like the power up kit). But I figured that for starters, I would put no preload on the valve, so the waste gate would actuate at 7 psi, and then adjust from there.

Well the boost controller I have is just a check valve with a preload, it doesn't bleed off pressure to the waste gate actuator. However, there is a port behind the check valve that is open, such that you don't leave pressure behind the waste gate that would hold it open. I didn't think that this port would just bleed any boost that I had the whole time.

So I put the power up kit valve and went for a ride. Man, I am just too timid to hand any more than 6 psi of boost anyway, hehe. But it was fun, and on the highway, it's doing 85 at about 6k, making a few psi of boost, and it's just begging to go faster. So smooth, and the shifting is MUCH smoother than my 750 seca. I'm loving it.

I'll probably just leave it like it is for a while. I should probably change my oil now (a small amount of gas might have gotten into it from the first start-up). I also want to change out the o-rings in my fuel check valve, and air box drain valve.

Finally, my pilot circuit isn't quite right. After a couple of miles of warm up, my idle was really low, so I cranked it back up. After riding the highway for a while, I exited, and the idle was hanging over 2k rpm. I lowered it back down, but it had a tendency to hang a bit (although it would idle at about 1250 rpm). I'm pretty sure that a final good flush of my carbs pilot circuit, and a tune will get me there (plus I'm probably really rich now at idle).

Hopefully hurricane sandy isn't all that bad, and I can get back to enjoying my turbo seca soon!

 

Glad you got it figured out. Sounds like you've been bitten by the boost bug.

 

It's amazing how when I am reading about the turbo on this thread, I am completely clueless. One day I'll have to actually learn about these mysterious boxes of power. Congrats on the successful project!

 

Well it's my build thread, so I invite you to ask away fintip. I've got a degree in aero/astro engineering, so if you are interested in basics of a turbo in terms of thermodynamics, I can try to review and answer them.

If you are interested in how Yamaha actually turbocharged a motorcycle, and all of the details necessary to make it work, I can relate those as I have learned them (and I got a lot of info from JeffK, a member on this forum, who actually helped me rebuild my turbocharger).

I'm sure others might have similar questions, so the answers might help someone else in the future.

 

Well, I guess the basics would be a good place to start. With an emphasis on individual part names and functions, if possible ('wastegate', 'pressure valve', etc.).

The thermodynamics of a turbo interest me, but I am equally interested the the mechanical construction/function of the device itself and its related systems.

 

A turbo charger is a type of "super charger" (in fact the full name is turbo-super-charger. The idea behind a super-charger is to increase the pressure into the engine. According to ideal gas law, PV=nRT, so if you increase the Pressure (P), you increase the amount of reactants (n) per stroke, thus increasing torque and power for the same rpm.

Turbo-chargers differ from other super-chargers in that they are powered from the exhaust gases instead of being mechanically driven. Exhaust gases have energy in the form of heat, and the turbine (in the exhaust flow) converts some of this waste heat into work, through a shaft that runs the impeller (in the intake flow).

As the amount of energy in the exhaust increases, so too does work transferred to the impeller, and the boost pressure produced by the impeller. More "boost" means more combustion, resulting in more exhaust, and you get a run-away reaction. The waste-gate prevents the run-away reaction. It's a small valve in the exhaust system before the turbine. The vent is actuated by the pressure at the intake/impeller side. When the pressure is high enough in the intake, it opens the wastegate, allowing exhaust to bypass the turbo, reducing the conversion of heat energy into work, and therefore regulating the boost pressure at the impeller.

You'll also hear the term "blow-off valve." This is a valve in the intake that opens at a set pressure, usually higher than the waste gate actuation pressure. This doesn't regulate the pressure in the intake, as much as bleed off extra pressure that is produced when the throttle closes but the rotational inertia of the impeller (spinning up to 210,000 rpm) continues to produce boost.

 

How did your last ride go? you should easily see boost in second gear on the stock turbo guage when you open up the throttle. You should also feel it by the seat of your pants.. One thing that I have noticed with this bike is if your fuel pump is working and you are not feeling or seeing boost, do the cheap thing and replace the spark plugs. This bike likes to eat spark plugs and I would have the stumbling problem around 6k rpm and if I replace the spark plugs, it will pull through 5th gear through redline if you can hang on.. Yeah its a fun bike and will pick up the front wheel while on boost Just ask my GF

Sean

 

Well then something might still be off. Granted, where I am near DC, I didn't really venture far enough to find a road to open it up, and I haven't really taken it to redline in a hurry other than in 1st gear, and I didn't see any boost then.

I'm not sure if I'm just being too timid with it (a possibility) or if there's something else causing a lag. I don't think it's the waste gate, because it seemed to seal well, so maybe I'm losing pressure on the intake side. I do know that the check drain valve o-ring wasn't replaced, so I'm going to go back in and do that (along with the fuel check valve o-rings). If it's not a leak, then something is keeping the turbo from really spooling up. I did rebuild it myself (with some help) so I could have botched the job.

The engine itself spools up really smooth and quickly, but I didn't really get boost unless I was going highway speeds, even then, it seemed to take some time to build up, but once it was there, it was edging me on. I'm sure I'm just a bit of a wuss, but it was a bit disconcerting seeing the boost needle in the green, and 80-85 mph in 5th, in traffic, and the bike really felt like it was ready to take off at a moment's notice. The slightest coaxing, and it was ready launch at those speeds, but I didn't push it, both due to the traffic, and the tickets I don't really need. So it definitely produces boost, but I'm not sure that I'm quite getting the performance you describe.

I might take it out one more time, but I really think that the pilot circuit might need a little more of a flush. I cleaned and rebuilt the carbs, then spent a while fighting with the fuel level, setting, so the pilot circuit could have gotten clogged again in that effort. I really need to change the oil again, especially since it definitely got a little gas in it from the first start-up when the floats all got stuck. Also, I'm running a 20W50 motorcycle oil, could it be too thick for the thrust bearings? I was thinking of going with the Shell RotellaT 15W-40 for the next oil change, both because it's thinner and closer to Yamalube spec, and because my 750 Seca really likes it.

Other than the flooding from that first startup- the plugs are new. I did hose them down with carb cleaner at one point when I was trying to tune the idle because something was way off, so I needed to keep the choke on and they were all sooty.

I haven't tried to verify the pressure output of the fuel pump (don't know how) but I have confirmed that it flows fuel at a pretty good rate. All of the relays work, and I can see the pump working through my inline fuel filter.

 

I took it for it's third ride today and have put 100 miles on it so far!

I'm getting boost earlier now, much like everyone's been saying. For my first two rides, I was very concerned about scrubbing the new tires, but now, I'm starting to launch a little more and have fun with it.

I was riding around River Road along the Potomac, a hilly road with gentle curves and a 50 mph speed limit. I was running low on gas and decided to turn around, and where I did I was actually facing uphill. I dragged out first, and didn't even get out of second before I was doing the speed limit and crested the hill, but WHAT A RUSH! I definitely saw PLENTY of boost (and felt it too) all the way up.

So now to fix the little things. We are celebrating my wife's birthday next weekend, and it's starting to get colder here, so we'll see how much I can really get done.
1. Off idle performance is a little weak. I think the pilot circuit must have clogged. There were months between my carb cleaning, float height setting (which resulted in the carbs overflowing numerous times) and final running, so the pilots circuit might just need to be flushed again.

2. Brake fluid warning light is on. I checked this after my first ride and found that I had swapped the leads. The switch grounds the circuit, so it's likely that there it's getting grounded for some reason.

3. Oil change. I also need to change the little crush washer on the drain plug. Although I haven't seen too much oil dripping, there is still a smell of oil. I haven't seen oil dripping from the left exhaust weep hole, so maybe my oil check valves to the turbo are working better now.

4. Rebuilding the fuel check valve and replacing the o-ring in the surge tank drain.

Then I get to focus on more cosmetic enhancements and performance mods

1. Fix the left lower chin fairing. I drilled the hole wrong, so now I've got to fill it with fiberglass, and try again. What a pain...

2. Boost gauge. I've got a boost gauge reading from the surge tank (the same place that the waste gate actuator gets its signal). On the recommendation of JeffK, I installed it on one of my side panels, but I really have to take my eyes off the road to see it. Obviously, I should be watching the road, not my boost gauges, but I suppose it can't be helped. I bought an extra plastic dash, so I'm going to try cutting it up and installing the gauge over my other gauges. I need to wire the light for it too.

3. Get a clock. There's lots of room on the handlebar cover.

4. Set up the suspension. Maybe next year I'll replace the front fork springs, and try some cartridge emulators from race tech. I don't know what to do with the rear shocks yet, but I really think I can improve the front a lot without using a whole different front end. We'll see how that goes.

5. Clean up the windshield. It needs a good polish. There's also a black trim on it that I need to figure out how to glue on. Anyone have any ideas what kind of glue would work?

6. Paint. At some point, I need to actually make my bikes look as good as they run.

7. Finally, figure out luggage. I've got an extra 750 seca tour pack that I want to install. The mounts to the frame don't fit however, so it's going to be a full custom rig that I'll have to weld. Unfortunately, although I did take a few weeks welding class, and I'm sure I could do it myself, I don't have a welder or anywhere to even plug one in. I really want this thing to be a sport tourer though (I have a feeling I'll be riding from DC to Boston often a year and a half from now).

 

I only have comments on a couple points.

1. Some of it may be a symptom of the turbo bikes. I don't know for sure. Boosted motors, as you probably know, are generally lower compression ratios to start out with and the off boost performance can suffer as a result. Though it never hurts to clean carbs one more time.

7. I have a 110v mig I could toss in the truck and bring down sometime if you want. Or I know a guy up in Mt. Airy who builds dumpsters out of a shop behind his house I'm sure he could work a deal to get you whatever you need welded. His welds are bulletproof, literally. He built targets for my shooting club.

 

Thanks for the comments:
1. I think it's the pilot circuit because performance is dead smooth above 3k rpm, but is really rough below. It feels lean when taking off from a stop. Also, when I put choke on when warming up, the engine will rev up to 3k rpm easily, although when warm it's idling at 1200. I think that this is because I'm idling on my off-idle circuit (which would explain the revving under choke, because dumping more fuel when the butterflies are open too far will cause it to rev rather than stumble from being too rich.

7. I might have to take you up on that offer somehow. The problem with my place is that there is only one little outside outlet on a light pole that I can use, and I'll probably just trip the breaker using a welder or compressor. And the breakers are in the downstairs apartment, and I really don't want to bother them. I'll probably be looking to complete this sometime next year.

 

Well I got some time today to clean the pilot circuit again, and man am I glad I did.

Of course, I also had an o-ring for the drain check valve in the surge tank (I found it in a parts bag after I had already put the carbs on), and I got o-rings for the fuel check valve to install.

Well I pull the drain valve from the surge tank and what do I find....THIS!?!?!?!



My first thought was eggs of some sort, but I cut them open and they appeared to be seeds (covered in a healthy coating of oil). The were mostly collected around the drain valve, but I did find pieces in the carb throat and even one whole one underneath the diaphragm of carb #2. I don't think they got there (or were put there) after I had gotten the bike up and running. The only thing I can figure is that they were put in the surge tank there by some critter, and since I couldn't really "see" inside the surge tank very well, they hid until everything got flooded with gas (on start up) and all collected around the drain valve (or made it's way to the impeller...maybe that's why I didn't get any boost the first two rides, they had to get blown out?). I didn't find any in the impeller, and there looks to be no damage anywhere, so that's good.

Also a good thing I was in the carbs again. As I was cleaning carb#3, it dawned on me that the main jets were different between carbs 1/4 and 2/3, and that I should double check them. Sure enough, carb #3 had a 127.5 main jet, so I checked them all and the inners and outers were switched.

Finally, I HATE DROPPING STUFF BETWEEN THE SURGE TANK AND BATTERY! Last time it took me over an hour to find a little nut that fell and found a nice place to hide. This time it was a bolt for the fuel pump. I search and search and search, looking in some of the same places as last time. The only difference this time was that the hose to the impeller was open. Thought, "nah, it couldn't be in there" and kept searching. Since I had pulled the right muffler off, and it was only one screw I finally gave in, and as I pulled the hose off, the bolt dropped right out. Good thing I didn't give up on that one.

Hopefully I'll have time to color tune tomorrow and get back on the road. The pilots from before were 2 1/4, 3, 4, and 4 1/4 turns out (1234), so things were kinda outta wack.

 

Thinking back, there were weeks when the surge tank and filter box were installed without the carbs or air filter, and without anything plugging the openings. Lets say a mouse (I've seen them running through my garage) decided to pack my impeller full of seeds. How worried should I be?

I think I'm going to take the turbo off and examine the impeller for damage. This could explain my no boost condition for the first ride and weak boost condition on the second. The intake of the impeller looked fine, but I can't see the outer vanes without removing the turbo and disassembling it.

Seeds aren't nearly as hard as metal, so if there isn't any damage to the impeller (and I'll have to pull the exhaust to remove the turbo, so I'll check the exhaust too) should I worry about any engine damage? I was really hoping that they magically got to the drain without hurting anything, but not I'm not so sure. The turbo was pooling oil until after my second ride, and these seeds looked oil soaked...

 

So I think the mice IN my garage must have put these things in my airbox/surge tank at some point when I had my turbo charger installed, but not the filter and/or carbs.

I pulled the turbocharger and disassembled it to inspect the impeller, and found this:



So it's a good thing I got in there. Really have to give a shot out to JeffK, who helped me rebuild the turbo this summer. Now it's no problem for me to pull it and disassemble it.

I tried to take a close up of the impeller blades. You can see discoloration on the right side at the outer tip of the impeller. I think the seeds did a "walnut" blast effect, removing some of the oxidation on the blades, but weren't hard enough to actually chip any blades.



So after cleaning all of that up, I did a compression test (this also primes the turbo with oil) and got 145, 145, 150, 155. So it looks like no permanent damage, and I think this is likely why I had boost problems early on.

 

Those mice can get into some queer locations... Glad you found that before anything got messed up! I'm jealous of your compression numbers too, pretty tight numbers!

 

I know I started this thread about three years ago when I bought it, but if you read it closely, it's that tight because the engine only has a little over 6000 miles on it

 

OH MY GOODNESS!!! THAT'S what you TURBO HEADS were talking about!?!? I just took the bike for a short ride after doing some colortuning and syncing. Riding leisurely up Old Georgetown Rd, a 40 mph street, trying to drag out first and second. I say TRYING, because every time I'd get a little over 5 or 6k, the thing would all of a sudden build boost and LAUNCH!

Two weeks ago, when the turbo kinda sorta worked, I'd feel it really pull when I loaded it up good. And I'd have a great big $h!t eating grin on my face. Now if I give it a little too much throttle for a little too long, it just takes off. And the look on my face is tempered with a healthy dose of dire concern, worried that I might just kill myself with this thing. Talk about non-linear power, getting shot out of a cannon is definitely what it feels like.

Furthermore, my carbs overflowed again. At the very end of my tuning, I tried to start it up once more and it wouldn't. The plugs were soaked with gas, and I think all of the bowls overflowed. I don't know if this is just going to happen every time I clean the carbs, or if I can fix this. I already installed new float needle assemblies.

I also had a bit of a back-fire problem while syncing. Pop and #2 blew the carb tuner hose right off while running. Shut the bike off and a short while later, another pop and #1 hose blew off too. Don't know if this was related to the fuel issue (I never saw any fuel come out of the drain, it all ended up in the cylinders).

 

Just read through this thread, awesome! Love the photos, so that's what my bike is supposed to look like! LOL Keep us posted on how you get on!

 

Nice going, great write up. Just did my carbs, they are still on my kitchen table! BD Design was great help with that. My experience with these things (This is my 3rd seca turbo) Be careful with the leaking carbs and check valve. I've had an oil pan full of fuel on more than one occasion with one of my other bikes (It perished in a garage fire which I think started with the bike, but that's another story) The line that feeds the waste gate can be plugged (remove the "filter" unit and replace it with something solid) now the pop off vale in the surge tank will open at around 15psi. Usually when you find used, parked seca turbos they are low miles. They will last forever once you start riding them on a regular basis...they get really cranky when they sit. Most people park them and then the develop issues, so they never ride them. The one I am working on now has 11,000 miles on the clock. The oil check valves seem to fail over time, spring gets week. You can clean them and sometimes that helps if they are leaking. Someone made some prototype check valves on tubomtorcycles.org, ( they have some good info on the site in the FAQ section on what the bike needs) but I don't know if they ever stared any real production and there's not much activity on the site. He also had an adapter to use a screw on oil filter too!
Another word of advise, if you haven't already, put a battery tender plug on the battery. If your battery goes dead, or you need a boost it is almost impossible to get cables on the battery even after you get the body work off. I also plan on installing an HID headlight, mainly to save on current so I can run my heated gear, but for way better lighting. You can also get progressive fork springs (I think they are still available) which makes a big difference in the front. Also, people recommend you replace the steering head ball bearings for tapered bearings. Replace the front brake lines with braided lines to help with the weak front brakes. The back shocks, about all you can do is replace them. The air system is okay for loads, but not great for handling. I also have a Canadian gauge cluster to get away from the 80 MPH American speedometer. The Canada one registers 240km with no red or orange lines. Haven't installed it yet, but it's an option. I'm enjoying your build, keep use posted!

 

Thanks for all of the advice. I've put it away for the winter (detached garage and christmas running around won't give me time to work on it til spring). But I've done most of what you suggest, save replacing the front springs (rebuilt forks), replacing rear shocks, and replacing steering head bearings (regreased).

wrt fuel leak. It's leaking when it runs, as evidence by gas on the overflow tube (I have the stock overflow set-up with two tubes) and I just replaced the check valve o-rings. Either I need to set the fuel level again (which I've set and verified many times, but sometimes they'll seem to spontaneously overflow). I am also suspecting the pressure regulator, since I can't really test or rebuild it. I have another that I might try out.

But it did seem to really overflow badly when tuning, so lots of starting and shutting off the engine, so I wonder if something, like the pressure regulator, gets stuck for a bit, pumping lots of extra fuel into the bowls for a short time overflowing them.

Thinking that the best course of action is pull the entire fuel system and set it up off the bike, and use it all to set the float height, tank, pump, and all.

 

Random turbo-related story:
A few years ago I was a member of the XJ Owners Group listserv, and a message popped up from a member in Vancouver who was frustrated with trying to get his turbo to run and wanted to give it away to the first person who replied. I live just a short ferry ride away from Vancouver and my first thought was to snatch it up and meld the parts with my 650 Seca/Maxim X hybrid and create the world's only 750 Seca X Turbo.
Then I started thinking about how much work that would be, and how the project would probably end up being either futile or deadly.
So I took a deep breath, gave my head a shake, and backed slowly away from the keyboard.
Probably one of my smarter decisions.... but sometimes I still wonder what might have been...

 

Great read, keep posting pictures and progress.

 

Well I know I said I'd put it away until spring, but with the warm weather (and wife being out of town) I couldn't help but make some progress.

I started by building this:


I forgot to take any picks of the setup while using it, but I did take one after I pulled the fuel pump and tank:



I had a different mount for checking the float height, but I suspected that I really needed to set the float height to spec with the ENTIRE fuel system put together, one to verify that all of the components where working properly, since I can't test the pressure regulator (decided to try another one that I had just in case), and to observe any difference that the 2psi in the fuel system makes.

Sure enough, all of my fuel levels were a bit high (and #2 overflowed immediately before settling to a 2-3mm high level), so I got them all back down to spec while the fuel pump was running. Now there's no overflow!

I really like this PVC carb holder setup (I've seen it before on this site). One of the really nice features is that you can drain only the carb that you need to test, and can adjust it's float and retest, all without removing the rack or draining the other carbs. You just have to be REALLY careful with the float needle when you drop the float. #2 ended up hitting the concrete, and the tip got a burr that I filed and sanded lightly. I verified that it wasn't on the sealing surface, but I might have to go in there to replace it later. No problems from that carb when testing the others, so I might have gotten lucky.

I really recommend testing the whole fuel system if you have a Turbo Seca, even though it takes a long time. I spent half an hour last night building the rig, and 5.5 hours today pulling everything, setting up, testing, and reinstalling, but now I don't dread the fuel system, since I KNOW it works. If the weather isn't bad tomorrow, maybe I'll finally get a good idle tune out of this thing.

 

how did you get on chap?