Friend just bought a 650 Turbo Seca in Albuquerque on a whim

My friend's grandfather (who raised him) just passed, and his family is crazy and he's having a terrible time with some ensuing drama of a high caliber.

So he does the logical thing and heads out to albuquerque with his uncle on an impromptu relax and collect trip.

On the way, he sends me a text pointing me to a craigslist ad for a 650 turbo.

It said this:

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Turns out the valves have never been adjusted (!!), and it doesn't idle well. Original tank was rusted to hell, bought a replacement that had minor rust that hasn't given problems for the last 2k miles, has filter. Had a buddy clean out the carbs who 'is an ex racer' when he first got it, bike never idled well. Selling because he got a new bike, doesn't ride it anymore.

My friend and I got him down to $950. Bogs and runs kinda poorly until the turbo hits and then rips away from you.

It's on the back of the truck headed here now. I'll have another XJ650 to play with (I do his bike work), only with upgraded valves!

Does the turbo use the same hitachi carbs my Maxim 650's ran?

Overview of major differences from turbo owners? Or a link discussing the engine upgrades and other differences? Titanium valves or something, right?

What should I know about servicing the turbo?

(Yes, I can and will do my research here, but some helpful pointers in the right direction can't hurt before I start. )

 

This bike is a SCREAM! I worked on one for a local collector who bought it and couldn't get it running. After I got it purring like a kitten, I rode it. And didn't want to give it back!
I can't recall if it had Miks or Hitachis, but Chacal had all the parts I needed. Get it running right and you will find you have a hell of a score there!

 

They have Miks, and special Miks at that (they're pressure-sealed against the boost) and just about everything on them is unique (and typically more expensive than their lesser cousins). Plus there's all the fuel pressure regulator plumbing on top of the carbs (which better work right!) and an explosion of fuel and overflow lines (routing instructions on bottom of seat pan and on side of tank) as well as some special electrical stuff and a vac-operated boost pressure regulator (pulls back the timing on the TCI), along with a vac can for the turbo wastegate (unless the boost-up kit is installed) and yada-yada-yada.

Fin, do yourself and your buddy a favor, get the Turbo service manual.......

And as far as "servicing the Turbo", if you mean the actual compressor, I would leave that to an experienced rebuilder. It's tough to tell whether a turbo unit is properly functional (and they tend to eat seals and then pump/burn oil into the carbs) and they depend on extremely proper balancing of the blades (they spin at about 200,000 rpms).

I believe user "Jeff" (??) knows a bunch about them. I'v had two of them and although they certainly are a thrill, they're a beast to diagnose and repair properly if you don't know the root cause of a problem (besides the basics, i.e. valve clearances, fuel levels, carbs internally clean, etc.) since there are so many specialized, interacting sub-systems involved.

A 14K bike that never had its valve adjusted speaks to how it was operated/treated over the last 30 years or so. Good thing you like challenges! Unlike the natural-aspirated XJ's, turbo bikes are much less tolerant of poor, sloppy, or non-performed maintenance.

 

I'm jealous!

and Len... I think that's the first time I've seen you fess up to owning a specific model.....

 

BDesigns has a great selection of Turbo and Carb parts for the turbo seca. Brian went through the trouble of making specific carb kits for these bikes (and a couple of others) but the price is good and the parts fit. Some stuff is much cheaper than the Yamaha Part alternative. Delivery takes a bit longer because it's coming from Canada.

Jeff helped me rebuild my Turbocharger. They were component balanced, so unless there is damage to the imeller or turbo, they "should" stay that way even when disassembling. However, we still went through the trouble of lining everything back up when we disassembled/reassembled. YMMV.

I would also recommend setting the fuel system up off the bike to verify your wet set float levels. It's a pain, but if anything in the fuel system isn't functioning properly, especially the pressure regulator, you'll flood your carbs in no time. If the carbs are on the bike that gas will all end up in the engine, and you'll just have to pull the carbs again (not fun). Also, as a side note, don't pinch the return hose when tuning (I just found this out the hard way). Same result as above.

All in all, the Turbo Seca IS going to be a lot more complicated than your Maxim to work on, as it really has just too much going on. Too much for it's time, and too much for even a modern bike. I've personally even gotten a little sick of trying to tune the carbs, since so much plastic has to come off just to get the the spark plugs. But now that it's dailed in, it is one heck of a bike.

I took mine down to the frame, completely cleaned the harness, cleaning, de-pinning and scrubbing male end of connector pins with Al-Oxide scrub pads, and using di-electric grease throughout. I've had no electrical issues since putting it back on the road.

Finally, the first thing you should to is get your valves in spec and test your compression. A turbo seca needs sooooo much to be right to be reliable, and you don't want to invest all of that money (and it will be a lot of money) just to find that the engine's blown because the valves were never adjusted.

 

You need to update your signature, manbot. Your thread was the first thing I was thinking of going through again.

Couldn't you just ride the bike without the plastics while tuning the carbs?

Thanks for all the great info. A manual is definitely in order. Anyone know of a forum for the turbo vintage bikes, maybe? All I can find is what looks like an old dead community called TMIOA or something and various 'websites' that look like they're from the 90's.

Manual will definitely be in order, hope I'm not in over my head here.

If the Turbo is functioning as-is, can I safely assume it doesn't need work? What are maintenance items for a running turbo? I can't imagine what kind of bearings must be used to spin smoothly at 200k...

 

Done. I was planning on updating that thread with my recent experiences tuning the bike, and pinching off the return hose...

I suppose you could. What I'm referring to is more the tweaks that you'd do after riding the first time. I'm used to my seca, pull the seat, unbolt the tank, put a 2x4 under it and I can get to all the plugs, even on the road.

Plain oil bearing only. Best thing to do is take the turbo to someone who knows turbos and ask if there is too much play. What will seem like nothing to a lay person will probably cause catastrophic failure in due time. And it's not like replacements will be easy to find.

I'm not sure TMIOA is all that dead. Last year Jeff was on it. It won't be nearly as active as this place given the number of Turbos on the road (and I haven't even joined it).

I'm going to tell you that it is a difficult bike, one that I'm not sure was worth the time I've invested. But I do love riding it (I probably just don't ride enough now). Every time that boost kicks in it puts a HUGE grin on my face.

I'm sure you don't want to hear this, but the maintenance list for a running Turbo is the same as a non-runner, especially if the PO wasn't taking care of it. Like chacal said, Turbos are not very forgiving of shortcuts, especially the fuel system.

 

Thanks for the info! And do the thread update! For posterity! Seriously, I've been reading a lot today, and your resto thread still strikes me as one of the better resources I've run across on the topic.

Not to make you update your sig again, but you should hotlink the bike to the build thread there.

 

Re: Friend just bought a 650 Turbo Seca in Albuquerque on a

So... Pumping oil into the carbs from the turbo. Seal's blown.

All resources on rebuilding the turbo accepted, how hard is this? Len, I know you mentioned having someone else do it--how much would that be? (Anyone else know?)

Friend is pretty bummed. I'm down for trying my hand at it if it's reasonable and doesn't require incredibly special tools--I apprentice at a motorcycle mechanic shop now, so I have access to a pretty wide selection of tools.

 

Oil in the carb doesn't necessarily mean that the turbo needs a rebuild. Could be a problem with the check valve. Or your carbs have overflowed and filled your crankcase with gas. If your fuel system isn't 100%, especially the pressure regulator, you'll overflow the carbs fast. Fuel pump outputs 14psi, if it's not cycling back up to the tank it flows WAY more fuel than the bike can use even at WOT.

You need to remove the turbo and take it to someone who knows turbos to tell you if it seems like it has an acceptable amount of play. Stop your friend from just running the bike and hoping everything is fine, or he'll end up doing a lot more damage to an unobtainum part.

JeffK recommended the following shop for either a turbo rebuild, or a rebuild kit:

http://gpopshop.com/

Rebuild STARTS at $350. I forget how much the rebuild kit is, but it's well over $100. I can try to find the link that Jeff sent me on the rebuild, however, it's not for our turbos specifically, and I had him helping me out for an entire evening. It's not an easy job, there's a lot of alignment things that you want to get right, disassembly and reassembly is tough with the GIANT c-clips, and there are some parts that are a little counter-intuitive.

Turbo Secas take a lot of work to get right when they've been neglected, and quite a bit of money. Your friend shouldn't be bummed, what he is experiencing is expected of a neglected bike. All is not lost, it's just not going to be as easy (or cheap) as he hoped.

 

We do carry the rebuilt turbos in both stock and enhanced turbo units (and jet-coated exhaust collector for increased turbo efficiency)....not cheap, but in-stock and ready to go, as well as rebuilt vac cans, vac lines, etc.

 

Chacal, what are the prices on those?

Manbot, (I do enjoy saying that), yeah, neglect is one thing, but dealing with the turbo is another. However, he bought it from a guy who said he had just taken a 600 mile trip on it not too long before and who was obviously being kind of dishonest and trying to get rid of it on whoever would take it.

btw, how would carbs filling the crankcase with gas get oil into the carbs? ???

How can I check if it's the check valve? (or: where should I start reading to figure this out myself?)

Great info, trying to help him by figuring this all out. He might be willing to buy a new one, might be willing to send it off to be rebuilt. If there's a $500 solution and it would just 'be done', I bet he would take that. Maybe even a bit more.

I need some good reading on these pressurized carbs. I'm assuming if I rebuild the carbs, adjust the valves, and rebuild the turbo (and I guess the check valve is maintenanced? Don't know exactly what that is/how it works), that it should then just be a matter of tuning, no?

 

Hey Fin, I just sent you a pm with the info about the turbo parts.

 

Well describe "oil in the carbs." Like they are burning oil? Or got dunked in a tar pit? I'm assuming the former, and that would mean that you have oil in the intake that is being drawn up to the carbs. There are two possibilities:

1. Common to all XJs, the crankase fills with gas+oil, oil flows out of the breather and into the airbox. It should drain from the airbox but that drain might be plugged. Also, other XJs don't have a fuel pump, which means a lot more gas can get pumped into the crankcase. We aren't talking a little piddle that fills over the course of a day, think a minute or two and the tank is empty.

2. Oil check valve. Since the turbo is low and behind the engine, it requires a check valve to prevent oil from flowing to the turbo when the engine is off. Check valve is located towards the front of the oil pan. If it fails (a common occurrence) oil pools in the turbo and can be sucked in on the impeller side, and must be blown or burned out of the turbine side. One thing you can do is drain the oil, remove the check valve, and flush it out with carb cleaner. It could just be dirty.

I put in my thread my set up for wet-setting the float height off the bike. If you do that, you'll find out exactly how your whole fuel system is functioning, as the fuel pump, fuel check valve, and pressure regulator must all work together to provide the right amount of gas to the carbs. You would disassemble and clean all parts involved in the check valve and flush out the pressure regulator. You can also test it with compressed air.

He very well could have taken a 600 mile trip. What was his gas mileage? Have you compression tested the engine? I'm sure a turbo seca could run with a crankcase half full of gas, but not very well and it'll be doing a lot of damage. Maybe that 600 mile trip simply came to an end because it wasn't running right?

 

I assumed it was because the turbo is oiled by the common engine oil and had blown seals, and so was feeding its oil to the carbs (via the airbox, I guess, if that's where the turbo feeds back into).

The crankcase was low on oil/fluid, so I highly doubt it is leaking gas into the crankcase.

For your check valve theory: I don't know enough about the design of the turbo, but shouldn't the oil lubricating the turbo still not contaminate the air flow passages if the bearings/seals are good? Interesting idea, though, I definitely want to check that out.

Can you take a picture of the check valve so I can make sure I know what I'm removing?

PO isn't around to ask anymore questions of, unfortunately. I mean, I guess Ihecould try and call him, but...

No haven't compression tested yet, but it seems that compression is good.

 

Look at the fuel inlet "T" fitting on the carbs (between # 2 and #3) and trace the very short (2") rubber hose from the inlet T back up to it's source..........that big T-shaped thing is the check valve..........the right horizontal arm of the check valve takes the output from the fuel pump, and left horizontal arm of the check valve goes to the pressure regulator..........all of this stuff is mounted onto a series of brackets that attach to the top of the center carbs (the carb hats), yes it's a congested plumbing nightmare.

 

1. PO's usually don't care how you are getting on about the bike. It's not their problem any more. Don't bother contacting them.

2. Chacal is talking about the fuel check valve, which is only in place to prevent fuel in the fuel from flowing into the carbs when the pump is off (if the floats were leaking I assume). I'm talking about the oil check valve. If you look for the oil lines coming from the turbo, you'll follow them to where they meet the engine. The end with a big hex-looking fitting is the oil check valve.

3. The oil seals and bearings are one and the same. You will always have some amount of leakage, especially when everything sits, as the turbo isn't really "oil-tight" so oil can be drawn through capillary action (again, we are talking about a VERY small amount, not something that is polluting the intake, except for when you start it after sitting for a while). As I said before, you evaluate the turbo by checking the play in the shaft. There should be none. Does that little bit of play count as none? (you'll ask yourself when you finally check it)...remove the turbo and take it to a place that is experienced with Turbochargers (any tuner shop, etc). They'll tell you if it's shot, and trust their advice.

4. Why do you think it is burning oil? What EXACTLY are your symptoms?

5. You need to check the compression to find out if the turbo is even worth working on. You can't "tell" the compression is good unless you put a gauge on it. You will need to dump $1-2k into a bike in that condition, and it's stupid to do all that work THEN find out that you need an engine. And Turbo Seca engines aren't just "swappable" with other XJs. Check the compression before buying another part.

Do you have a manual? Shoot me an email (i sent you a PM).