Simmy's Naked Turbo Project

I'm not aware if any replacement air filters are still available.
The foam seal was 1982 disintegrated so I sealed it with some adhesive lined foam I had on hand.
Probably thicker but it still fits on the bike ok.

 

Good to have friends with skills and tools. A retired guy I used to work with relocated the petcock mount from the Turbo tank on to the RJ tank.
Here he is cutting the mount out with his plasma cutter. This is all necessary because the Turbo has a larger and specific petcock.
There is a return line to the tank for excess fuel pressure.
s

plasma cutter does a real good job going around corners,

here he is cutting the mount out of the Turbo tank, we made it larger so it overlapped in all directions.

here it is fit up before welding

welded out and tested with diesel fuel. No leaks on the first attempt.

while I had the hole enlarged it was a perfect opportunity to remove the big dent in the top of this tank.
We put a curve in some 3/4" bar stock and we were able to punch most of it out.
A skim coat of body filler should smooth it out now.

 

carburetors are ready for the wet set.
I couldn't see anywhere what the fuel level setting is for the Turbo so I'm going with 1 mm below the top of the bowls like my 900 manual shows, they're both Mikuni's but if someone knows for sure let me know.
I've got the stock jet sizes (127.5 mains in 1&4 and 132.5 in 2&3) in there now.
I'm planning to up the boost. Is there anyone who has jetted richer for this?
If anyone has recommendations I'm listening. Maybe best to keep the boost below 11 psi for tuning purposes, wait for the silly stuff until later.

 

You are on fire and doing an exceptional job Simmy!

 

thanks Chacal. I think I read on your pages about increasing the jets size when increasing boost.
I think I will set everything up within the OEM parameters (stock jetting, stock boost pressure) to make any trouble shooting easier.
As stated above the XJ650LJ manual doesn't show the fuel level.
I filled the carbs with gas today and found all 4 at about 3 mm from the top of the bowls.
I think this will be ok. I can tweak them higher if someone knows for sure.
Otherwise the carbs are ready to go on the bike.

 

below is the RJ petcock mount. The threads are formed by just pressing out the sheet metal, pretty flimsy.
The Turbo had actual weld nuts on the back side, perhaps just because the petcock is bigger.

 

As long as your welding in a new petcock, I switch to the 22mm weld-in bung and use a Pingel. There are now much cheaper Pingel knock offs for only about $40,00 new.
Cheers, 50gary

 

nice thought but I'm not sure anyone makes a mongrel like this for blow-through turbocharged carburetor applications.

 

carbs were a complete bear to seat in place. I think this battle took me about 3 hours but I won, yah!
I noticed @Timbox used ratchet straps in one of his pics to persuade them in but I was worried about my new paint.
Moving on to the wiring harness now. My open-terminal crimping pliers have arrived and Chacal supplied new terminals where needed so I'm all ready for this now.
I still need to buy a smaller fuel pump with higher capacity.

 

Now you sound like me. Lol.

looking good man!

 

I bet there were some choice words being said putting them in like that. Nice paint though...and still that way.

 

I’ve had the carbs in and out countless times on my FZ and other Seca and just muscle them in by hand. Maybe the Turbo has stiffer rubbers to handle the pressure? Every choice word I have is currently needed for my investment portfolio. This keeps my mind off of that.

 

I put my turbo carbs on by seating one side, clamping, then seating the other. That way the first one doesn’t pop out.

It is a huge pain and much harder that the 750 Seca I had. I give up trying to seat them four at once. I can’t count the number of times I almost pushed the bike off the center stand trying to get them on.

 

Easy.
Cheers, 50gary

 

I took the fuel check valve apart to redo the 2 o-rings.
The little one was brittle and probably wouldn't hold back gas for long.
This bike does not have a vacuum diaphragm like the normal XJ's so relies on this to stop the gas when parked.
I'm more worried about the fuel pressure regulator but not sure they even come apart.

 

the Turbo manual shows the wiring loom hanging alongside the bike.
At first I was worried it might not fit under the RJ sidecover but it does.
I made a slight detour inside the frame since the RJ sidecover tab is where the Turbo puts the wire,
there was no problem as there is lots of room here.

 

Below shows the installation of the boost controller.
This is the cleanest routing but I thought about plugging the outlet on the turbo and getting the pressure signal from a tee between the surge tank and the fuel pressure regulator to trigger the waste gate. It probably makes no difference but the pressure at the surge tank might lag the pressure at the turbo.
I'm thinking it won't matter since I plan to adjust the controller by measuring the boost pressure up at the surge tank anyway.
I put a dedicated line between the boost pressure sensor and the nipple present on carb #2. I think it's important not to have any tees in this line.

 

I copied this below from Walbro's website.
It looks like model 395 is closest to the specs needed for a Seca Turbo with a little more boost than stock (OEM pump is 14 psi).
Ebay is full of GSL392 Chinese knock-offs at less than 1/2 the price of a genuine Walbro 392.
Does anyone foresee problems with a fuel pump capable of pressures way in excess of what is needed?
395's are not common but are available from Walbro.

CHOOSE FROM FIVE GSL INLINE PUMP MODELS:
Part # Rated Flow* Typical PSI Max PSI Max HP (NA)* Max HP (Boosted)* Applications/Notes
GSL392 255 LPH 43.5 psi 87 psi 670 HP 540 HP Great choice for Carb to EFI conversion (Including GM LSx)
GSL394 190 LPH 43.5 psi 87 psi 500 HP 400 HP Great choice for Carb to EFI conversion (Including GM LSx)
GSL391 190 LPH 43.5 psi 50 psi 500 HP 400 HP
GSL393 155 LPH 43.5 psi 50 psi 405 HP 330 HP
GSL395 130 LPH 15 psi 20 psi 340 HP 280 HP Low Pressure: GM TBI Engines, Carbureted engines w/return-style regulator
*at typical PSI. Pressure is set by the regulator--not the pump. Flow will decrease somewhat as flow increases. See chart provided for each pump.

 

the current draw of the 392 is about 6A at 10 psi
the current draw of the 395 is only 2A.
So there's my answer, I think I'll order the 395 and avoid the Chinese s#!+

 

I went ahead and ordered the Walbro 395 fuel pump, with 15 psi nominal, 20 psi maximum and similar current draw to the OEM pump it seems like the best fit.
I'm looking for any recommendations for cheap pressure gauges. I say cheap because I don't plan to keep them on the bike.
They would only be for set up purposes.
I plan to set up a gauge between the boost controller and the turbo to accurately set the pressure for the wastegate.
At the same time I'd like another gauge up at the surge tank to find out when the BOV pops.
Ideally it would stay at the peak pressure observed. Anyone have any experience with this?

 

I'm not sure how much difference there will between the surge tank and waste gate. I have them plumbed to the same line. Something else I've noticed is that there is a bit of staging, you won't see the waste gate open immediately, and the pressure will rise over the wastegate setpoint before falling and settling on the pressure you want. This is due to inertia in the compressor compressing some air before exhaust bypassing the turbo slows it down.

The blow off valve isn't there to regulate boost, it's there for when the throttle bodies slam closed and cause a pressure wave back into the surge tank. If you are interested in raising the boost pressure, I'd just do the calculation on the spring preload that is set up stock, and increasing that to get the blow off pressure you want. It'll probably be close enough.

A lot of the pressures in the surge tank are not going to be steady state, they will be very dynamic. You won't be able to measure or set them up without very sensitive equipment. Cheap gauges are great for knowing the steady state running condition if anything changes. I don't think there will be any "cheap" ones that will hold peak pressure. Don't get anything is a negative range (you aren't going to measure vacuum at the surge tank) and get one that's in the turbo operating range (0-15psi vs 0-30, etc). Finally, a lot of movement will wear out the mechanism, so oil filled gauges are best if you decide you like to watch the needle move.

 

Thanks for the reply ManBot. I did slip a washer behind the spring so the BOV will hold more than stock. I have another washer I can measure the thickness, I apologize, I know you explained this to me before but I didn't calculate anything. I'm thinking this old spring has been under preload for 40 years, who knows what its rate is now. I was told you want the BOV able to take 2 psi more pressure than the wastegate, just so you're not mistakenly popping the BOV first.
Do you know what the stock spring holds to?

OK I'll give up on the idea of monitoring the surge tank.
Since the fuel pressure regulator keeps fuel 2.8 psi above the boost pressure at the carbs, would it be any value trying to measure the fuel pressure?
I want to be able to adjust the boost controller without popping the BOV first.
I'm going to order this cheap gauge. I know you said not to get a negative reading gauge but this one is right in the +30 psi range.
As I said, it will be just for the set up.

https://www.ebay.com/itm/2-52mm-Aut...0-PSI-Meter-W-Blue-LED-Backlight/293532710826

 

Haha, I thought I had answered this before somewhere . If you want to take the surge tank off, plug up the turbo and carb outlets, tape down the reed valves and pressurize until the BOV opens, that would be an "easy" static test. I'd use a bike pump so it's slow and won't hurt anything.

For the gauge, an Auto Meter gauge like this would work well if you aren't trying to boost over 14 psi. The problem with vacuum/boost gauges is that there is quite a bit of "flutter" in the surge tank port as the boost starts to build, and the cheap ones will fatigue and set on the wrong "0" boost measurement. But that gauge is pretty cheap...

Fuel pressure gauge was to alert me if the fuel pump or regulator ever stop working. Also functions as a very good indication that you forgot to open your petcock . They aren't cheap tho, you need a digital sensor since it's in the fuel stream.

 

Well you extra time now. The 2019 Paris Rally just cancelled. So I can't wait till 2020 to see this bike.

 

I got the year wrong 2020 is cancelled. Can't wait for 2021 rally. Been isolated too long. Send help.

 

Yes very disappointed the rally is cancelled. This thing was not going to be ready this June anyway. Perhaps we’ll see the Carlisle swap meet in the fall. How’s your 2nd Seca coming?

 

2nd Seca is done just needs a battery. I don't know what to do with it. It is nice to have a second bike for parts.

 

I finished the mods to the wiring harness today.
I salvaged the connector blocks from the RJ harness and bought new terminal ends so now the entire XJ650RJC headlight, tach, speedo and dash lights are plug'n'play.
It's a good thing I'm using the monster 9" headlight from the RJ to hold whatever is still necessary.
I added the 2nd diode block from the RJ just for the low oil level light as Jay and Rooster recommended, and using the RJ oil level switch.
I've eliminated the emergency cut off switch, not really great since the fuel pump will continue to run after a crash now.
I might be able to hide it in a level spot behind the steering stem, maybe later, the plug is still there.
I'm still planning to band this mess up tighter and add tape anywhere vibration might rub on the wires.

 

I received my new fuel pump. Good news it is smaller than the OEM so it will fit under the RJ tank.
As I discovered earlier the LJ tank is concave in the area of the fuel pump.
Now just a matter of hooking it up.

 

I had to order these on-line. All my local auto parts stores did not have anything to go from 6 mm to 5 mm.
My boost controller has 1/4" (6mm) hose fittings and the turbo vac hose is all 5 mm nipples.

 

There was just enough room to fit the pump a little lower to fit under the RJ tank.
The wiring loom will fit right beside the pump.

 

I like how you mounted that pump, creative and effective.

 

I like how you stuck with metric bolts. You have an eye for details .

 

Thanks guys, the pump came with the mounting clamps and I had the clamps to go around the frame left over from a previous project.
It's a crowded cavity now and not something I'm looking forward to emptying, next time I need to pull the carbs.
I connected 12V to the OEM pump and couldn't get it to move. Reversed the voltage trying to rock it back and forth but no luck.
I've read some have revived them by soaking in various solvents, tapping and reversing voltage etc. I have no use for it, just wondered if it still worked.
I'm waiting for a few terminal ends from Chacal so I can still use the same Yamaha 2-wire connector block to connect the pump to the original wiring.
I haven't installed any dedicated fuse for this pump, the OEM circuit is all tied back to the 10A ignition fuse so what protected the OEM pump should be good for this one.

In regards to the vacuum tubing, I will have 3 separate hose systems not connected to each other.
I've illustrated this below

 

the boost gauge came with 1/4" nipples so I bought some hi pressure 1/4" fuel hose and downsized it to the 4 or 5 mm hose of the original turbo hose.


I mail ordered a $12 mechanical boost gauge I'm going to hook to the plastic tee above in the pic.
I'd like to try running the bike at 15 pounds boost to start the shake down runs.
Once it's running nice I'll remove this tee and run the hose directly from the turbo to the boost controller and eliminate the gauge.

I'm planning to hook up a bicycle pump and pressure gauge and statically set the thing to pop at 15 psi.
That should get me close to 15 psi dynamically measured when on the bike.


I found one supplier in the US which sold these.
there were plastic ones but they were the same price.
3/16" fits the OEM Yamaha hose, which I have a length on order from Chacal


I had these fittings on hand. The red colour bothers me so I might have to paint them black.
One of them will actually show.

I'm going to mount the boost gauge here on the left in front of the battery so you can access it by removing the side cover.
I thought there would be room under the seat but there's already enough stuff there making access to the air filter difficult, I didn't change anything there, that's the way they are.

 

all other XJ's are a pain in the ass when it comes to mounting the air box.
The Turbo is in 2 pieces (surge tank & air filter housing) and can be the last thing installed.
I tried fitting this assembly twice with the filter falling out of the housing before I had it in place.
not gonna be a 3rd time, I put 2 small swabs of goop to hold it in place so waiting for it to set at the moment.




air box cavity

 

I'll probably take some flack for not immediately fixing the fuse box but it passes the visual for now.
This bike was never stored in the rain so it's probably as good as any of them from 1982.


Eventually I'll install a new fuse block into the OEM box like I did on my FZ.
It actually accepts a longer fuse than this Japanese standard used by Yamaha.
I like using glass fuses, old school.


I found these at an electronic clearance house. They were cheap so I bought enough to do all 3 of my old Yamahas.
The Seca on my sidecar is still running with the original box but that bike has barely seen any rain.

 

I ordered a bunch of 90 degree barbed hose fittings for the 8 mm gas lines.
I'm going to put some in this line running between the pump and the regulator so it fits up tighter under the tank.

 

I stripped the petcock down and simmered it in my ultrasound tank then blasted it myself with baking soda.
There was a black tar like goo in there.
Replaced all the rubber components and installed a new wave washer.
I installed new filters but also put a filter between the tank and the fuel pump

 

Doesn't look like much but except for a few connectors for the tail light all wiring is complete.
Replacement coils are on my wish list. I have new plug caps to go on.
I also bought the OEM style straps for the wiring loom I need to install same place they were originally.
The zip ties are only temporary.


you can see the cheap aquarium tubing running from the tee in the line just before the boost controller.
Once I've set my boost controller I'll take the tee and the plastic hose out of the circuit.


This cheap Chinese boost gauge will only be temporary so I'm going to mount it in place of the left mirror for tuning.
I can make up a simple bracket to hold it.
I don't want to clutter the appearance of the twin clocks of the RJ with Chinese crap.

All new turbo vac lines to and from the Turbo.

The Turbo and a few other XJ's (750 Seca I think is another) have these tabs on each side of the frame to hold different grab handles.
When I powdercoated the frame I left them in place thinking they were not in the way of anything.
The one on the RH side actually interferes with the seat when hinged open so I took the die grinder to my beautiful shiny frame.
I touched it up with a brush already.
The wheels are off the bike for mounting new tires.
I'm actually getting close to firing this up.

 

Once I have a roller I'll just take it to a local bike shop who makes custom brake lines.
I'm planning to keep the RJ brake hose splitter so I will need 3 separate hoses.
The top hose should be same as 650RJ but the bottom lines need to be custom fit for the FZ calipers.
I still need to rebuild the master cylinder.

 

Temporary boost gauge mounted in place of left mirror. Even painted it black.

 

Start it already!

 

yep getting real close.
Wheels are being dropped off tomorrow for Bridgestone Battleaxe BT45’s. Time to buy a battery now to.
Need to flush out the fuel tank and could start it to synchronize the carbs. Still no front brakes.

 

can anyone explain what #27 does? No other XJ seems to list it.

 

Is it a hold down for the gas tank or seat?

 

It holds the gas tank in place.........unlike non-Seca tanks, the rear mounting flange is not visible/accessible on the Seca tanks, the rear edge of the actual tank "hides" the mounting flange. That clip slides over the bolt (#7) and clips over the tank metal brace, thus holding the rear of the tank down.

 

Ah, that explains why I have such a hell of a time getting my other Seca together with just the bolt.

 

the FZ600 donor bike came with an aftermarket front fender and it was missing the peanuts underneath holding the captive nuts.
The way the fender was gooned on was worthy of the DPO hall of shame. Remember the same idiot had the variable dampers in upside down.
I spent a couple hours last night fabricating the peanuts and drilled the hole for the speedo cable grommet.

 

Remember this when wielding "Grinder and paint makes me the wielder I an't".