Oil in Exhaust

**flyingace** · 06-12-2006, 10:31 AM

By my calculations, that's about a quart every 400 miles. That is quite a bit of oil. There are two ways oils enters the combustion chamber: worn rings or worn valve guides (or both).

The first step is to check engine compression. Less than 100 PSI on any cylinder means a rebuild. For diagnosis, you can put a tablespoon of oil into the low cylinders and repeat the compression test. If it goes up quite a bit, the rings are bad. If the compression is good on all cylinders, it's probably worn valve guides. Either way, it sounds like a rebuild is in your future.

I guess there's no reason you can't drive the bike into the ground if you need to. I think by the time any real damage gets done, the smoke and noise would be so bad you couldn't ride it anyway with getting arrested (if it runs at all).

Other opinions on this?

**bwringer** · 06-12-2006, 10:46 AM

I seriously doubt the valve guides themselves are worn, but I would bet that the valve guide seals are toast. This is VERY common in car and bike engines, especially engines that run rather hot in hot climates. The rubber gets hard and cracked.

This requires removing the head and the valves to replace the seals, and anytime you have the head off, you must replace the base gasket too. This is actually pretty easy -- it's a rather simple engine.

You can also replace the valve guide seals without removing the head if you use an air hold or some other means to keep the valve from falling into the cylinder while you remove the bucket and keepers to reach the seal. One manual I saw recommended simply feeding in a length of clean rope to fill the cylinder temporarily. Many car mechanics will be familiar with this concept -- valve stem seal replacement is a common job on OHC engines.

But do the compression test with the oil to determine if you need new rings and/or pistons.

**hungryman** · 06-12-2006, 11:59 AM

Originally posted by bwringer

I seriously doubt the valve guides themselves are worn, but I would bet that the valve guide seals are toast. This is VERY common in car and bike engines, especially engines that run rather hot in hot climates. The rubber gets hard and cracked.

This requires removing the head and the valves to replace the seals, and anytime you have the head off, you must replace the base gasket too. This is actually pretty easy -- it's a rather simple engine.

You can also replace the valve guide seals without removing the head if you use an air hold or some other means to keep the valve from falling into the cylinder while you remove the bucket and keepers to reach the seal. One manual I saw recommended simply feeding in a length of clean rope to fill the cylinder temporarily. Many car mechanics will be familiar with this concept -- valve stem seal replacement is a common job on OHC engines.

But do the compression test with the oil to determine if you need new rings and/or pistons.

Exactly. Do the compression test to get a handle on the condition of the motor.

I agree that it's probably the valve seals. But, you need to pull the head to do this as a practical matter, (yea you CAN do it without pulling the head, but why?) so you will want to know before hand if you need to replace the rings. While the head is off, I would also have the valves ground and check the valve guides. In other words, do it right, not a patch job.

**Duran** · 06-12-2006, 12:17 PM

so what would all you guys say to a bike that is using about a quart of oil in a days ride probably close to like 100 miles, with no fauling of the plugs?

**cberkeley** · 06-12-2006, 01:03 PM

Thanks for all the responses folks. I will do the compression check tomorrow and report back (hopefully I can borrow or purchase a compression checker as I simply can't find mine). Hopefully too, it's just the valve guide seals. Yes, if I do remove the head a complete job will be done, including taking the opportunity to drill out and re-tap those two exhaust bolt holes where the bolts broke off with the previous owner.

**Jethro** · 06-12-2006, 01:09 PM

Originally posted by Duran

so what would all you guys say to a bike that is using about a quart of oil in a days ride probably close to like 100 miles, with no fauling of the plugs?

I'd say "holy crap, Batman, you got a problem!"

Same advice for you as above, perform a compression test both wet and dry. That is too much oil to lose in 100 miles.

**hungryman** · 06-12-2006, 01:13 PM

Originally posted by Duran

so what would all you guys say to a bike that is using about a quart of oil in a days ride probably close to like 100 miles, with no fauling of the plugs?

I'd say that you probably have a leak.

**flyingace** · 06-12-2006, 03:24 PM

Sorry for the misinformation. I honestly believed that worn valve guides were what allowed oil to fall into the combustion chamber.

**Duran** · 06-12-2006, 03:55 PM

doesnt leak at all, just seems to burn it up. dont know if its the valve seals or bad rings, bike runs good, just burns oil.

**bwringer** · 06-12-2006, 06:16 PM

Originally posted by Duran

so what would all you guys say to a bike that is using about a quart of oil in a days ride probably close to like 100 miles, with no fauling of the plugs?

I'd say you don't have a mosquito problem in your neighborhood...

Seriously, check your compression like yesterday. I'd be pretty surprised if that much oil could get past bad valve guide seals, but who knows. In a car, I'd say check your PCV valve, but on a GS, just make sure the breather can breathe -- make sure the hose isn't blocked or kinked. You probably have ring problems, though.

**Jackyl** · 06-25-2006, 02:29 AM

Similar issue

1980 GSX750E

First let me say I looked at Cletus' website and checked out the restoration and WOW ! ! ! ! that is amazing Cletus, unbelieveable, you dont miss a thing, incredible job ! ! !

I am contemplating a complete rebuild, but like Cletus, I was curious the best place (on-line, I live in BFE) to get the kit, also, should I just pull the piston housing and do the head and lower gasket and rings, or is it advisable to do rod & main bearings as well? ( I only have ever done this in a car, Im not sure what translates).

I have a clymer manual coming, and this is going to be a winter project (here in Wyoming we have a lot of winter to work with lol, probably a december start for this project). Im not losing a lot of oil, but now that I have straightened out my fuel and electrical issue, on the highway (with a bit of wind, this is after all in Wyoming) at full open throttle Im struggling to hit 75mph most of the time. I did a compression test trying to find a dying problem (see my thread ) and the cylinders were, from 1 to 4, 125 - 100 - 75 - 120. so I know I have a problem on #3 cylinder.

Is there anything else I should do valve or head-wise while I have it out of the frame and apart ? Any suggestion would be great and Ill keep reading here in the GSR, thanks.

**cberkeley** · 06-25-2006, 10:03 PM

The local bike shop says that its probably just stuck oil-scraper rings and advise that I spray about a tablespoon of penetrating oil into the offending cylinders and let it stand overnight. Then next day, blow it out, start the bike and run it hard and see if the problem goes away. Does this make any sense?
I am yet to make an adapter so that my compression guage will fit the GS (maybe next weekend).

**Clone** · 06-26-2006, 07:13 AM

1 quart in 100 miles would blow smoke like a fogger:shock:
If your plugs are not all oily and black, then
a) you have a leak somewhere off the block
b) the exhuast guides are allowing oil into the exhaust port and then blowing out the mufflers, but this would still cause smoke as the engine heats up. Also oil would drip out of the drainage holes on the bottom of your mufflers.

Oil in Exhaust

Oil in Exhaust

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