oil running from exhaust

[DEmily]

Hey all. I recently posted an issue I was having with my 79 xs11. After rebuilding everything, I finally got the thing running great. But then number one cylinder started pumping oil out the exhaust. Compression was good on all four and it ran like a champ, yet it was dumping oil out the exhaust. No smoke, just oil.
You all gave alot of great tips and ideas, and I finally pulled the head to inspect it. I decided to replace the valve seals again thinging something had to have gone wrong on number one exhaust seal. While inspecting the head very close I noticed something that I had not before. Number four exhaust valve is missing the valve seat spring. Hopefully I am using the correct name for it. It is the washer type seat that sits in the head for the valve spring to rest upon. I am quite suprised as the valve shims are all close to the same and I would think that valve would be way off without that seat. I would also think that at some point it could start chewing the head up. Anyway, does anyone have any idea if this will be a part that is hard to find? Do other models us this same seat? I have had such a difficult time finding parts for this thing, I have some concerns. Can a hardened washer the same size be used? Any info would be greatly appreciated.

[TopCatGr58]

Hey there DEmily,

Well, that part # is 1J7-12116-00 according to my copy of the fische, but I don't know if it's still available. The clearance would not be affected by it not being there, the valve is the same length and the lifter sits atop the valve. The seat protects the softer aluminum head from the beating of the springs, and the thickness, albeit small, would provide a little more tension to the springs vs. it not being there. I don't know if the lifter reaches that far down during it's travels, so I don't know for sure if it (plain washer) would need to be sized to be able to provide a wide enough surface for the springs to sit upon, yet still fit within the diameter of the underside of the lifter. My hunch is that the lifter doesn't go that far down, or you'd have lots of impact going on!! HTH. Hope others can chime in here. However, I don't believe that it's presence or absence would be contributory to your oil leak, still think it's the seal around the valve so you're on the right track.

Did you inspect your valve stem to ensure that it didn't have any knicks or carbon built up on it that could have cut the valve seal!?
T.C.

[DEmily]

Yes, I have check about everything. All the valves are new and clean. Oddly enough the valve that is missing the valve seat is not the one leaking, it is , however the valve that bent on me for no appearent reason after I first finished the motor about three months ago. I will have to check to see if they are still available.
If not, I guess I will have to do some serious looking for a flat this hardened washer that can be made to fit.

[ratbyk]

Missing Washer

If you go to almost any good quality engine machine shop you should be able to get this washer. Most engine shops that do much cylinder head work have assortments of these washers in different thicknesses. I believe they call them "valve spring shims".
They are used after a valve and it's seat have been recut. The valve protrudes farther into the cylinder head which reduces valve spring pressure. This pressure is restored by putting a thicker shim under the spring. Usually available .020-.030 and .040 thou thicknesses.
It is also standard on all engines using alloy heads to prevent the spring as it rotates from "eating" the head.
Ken?Sooke
78E Ratbyk
82 FT500 "lilRat"

[crawlspace2112]

this part sounds like a spring locator shim or something similar. it would help keep the propper spring height and pressure in relation to the valve stem, without it you may not have enough spring pressure to seat the valve fast enough at high rpms causing valve float which would explain the bent valve. try a cylinder head shop especially one that specializes in imports. they should have something that will work even if you have to use more than one. they usually come in .015, .030 and .060 (these are thousanths of an inch) take one you have out and get them to measure it right there. you could probably modify one from a dodge or chev to work. lifter travel would not bottom out on the shim, the valve spring does not get compressed all the way either. you have room to play no problem. now the oil problem on one, what does the cylinder wall look like is it all glazed up? does it have a vertical scratch in it? you said it doesn't smoke but if it's coming out of the pipe then it should naturally burn from exhaust temp (approx 500 deg i think) is the cylinder running cold? fouled plug? any indication of a problem other than the real obvious oil in tailpipe?

[crawlspace2112]

hey ratbyk dejavu, your posting wasn't there when i started.

[ratbyk]

dejavu

Crawlspace2112, great Canadian minds think alike!
Ratbyk

[Geezer]

I don't think a missing lower spring seat will cause this. If the oil were entering the combustion chamber, you'd be seeing smoke.

I'd bet you have a cracked cylinderhead casting.

Geezer

[DEmily]

Man, I hope it's not as bad as a cracked cylinder head. Isn't it possible that the exhaust valve seal could cause this?

[DEmily]

The oddest thing about this is the number one cylinder is not fouling out. It is slightly wet, but hitting every time. The bike runnings like a champ! It is the strangest thing.

[Geezer]

Originally posted by DEmily
The oddest thing about this is the number one cylinder is not fouling out. It is slightly wet, but hitting every time. The bike runnings like a champ! It is the strangest thing.

If the oil is indeed being cycled throug the combustion chamber it's posible that you have a valveguide that is loose in the head. With that much oil comming out, it would have to smoke like a James Bond car.

Geezer

[crawlspace2112]

you said you rebuilt this motor. did you do any valve work? because of the extra heat the exhaust valves are usually allowed a little more clearance for expansion, look in your manual for clearances. extra care must be taken when removing the valve, if you have any burs on the stem and you pull it you can damage the guide and it really does sound like a valve guide problem like it came loose in the head. i would pull the exhaust valve, if it binds as you pull it out file the top edges of the stem around the lock chanel to get rid of burrs. then look very closely at the stem for material transfer or scoring of the stem. these valves look coated like an anealing process to give it a harder exterior. once that coating is gone it wears very quickly. if you have access to a caliper check the diameter at the top of the valve where it is not worn then check the diameter where it's in contact with the guide. it should be no more than .001 difference i would even question it at 3/4 of a thou but for the amount of oil your getting it would have to be a dramatic difference like .003 or something like that. the guide itself can and should be checked for correct diameter too. by the way you don't need a spring compressor to take the stem locks off, just a hammer and an appropriately sized socket they will fall out with a fairly forcefull hit. but you do need one to put it back together .

[Hobbit]

oil

When you rebuilt the engine, did you make sure that the ring gaps were not lined up on the piston?

[DEmily]

Thanks guys,

I did check the valve guide. There appears to be no binding. I will mic out the stems. As for the rings I did set the gaps as suggest in the manual. I did notice something just last night on the number one and number three cylinder walls. I very faint line or scratch running down the wall. The scratch is very faint and does seem to line up with the top ring gap on both. Something else I had not thought of until last night. The oil running problem did not start until I installed the new excell coils. At that point all four cylinders began to hit everytime. I then synced the carbs and took it for a ride. Right after that the oil running began. Now I had rode it previously several times and did not have the oil proble, but was having a very rich exhaust. That is what lead me to check the coils. So it seems that when the number one cylinder began to hit everytime like it should, is when it all began. Is it possible the fuel rich problem I had with weak coils caused a kind of gas wash on the rings and walls? Of course this still does not expleain how I could be running so good with no blue smoke yet dump oil out the exhaust.

[CA.XSer]

The oil running problem did not start until I installed the new excell coils. At that point all four cylinders began to hit everytime. I then synced the carbs and took it for a ride. Right after that the oil running began

Is it possible there was oil in the exhaust system after the rebuild and with the new coils and all cylinders firing blows the oil out?