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Oil/gas leak cylinder not firing

  • Thread starter Thread starter patrickh
  • Start date Start date
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patrickh

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Been lurking for some time and I feel bad that my first post is asking for help but I'm at a loss. My 1980 GS850L (I know) with 11,000 miles started running rough several days ago. It started to leak oil (definitely oil not carbon and gas) pretty steadily out of the joint between the headers and the muffler. I also noticed a gas smell. Also noticed gas and oil dripping from the engine around #2 header plus smoking when you revved the throttle. Pulled #2 plug wire and no change to how it was running. #2 is definitely not firing.

What I have done so far. Switched plugs, Swapped 2&3 plug wires (no change still #2) I checked compression. #2 was the lowest at 120. If I recall correctly #1 was 140 #3 was 125 #4 was 135. Also valve clearances were in spec. I was thinking maybe carb related but would that explain the oil and gas leaking? Decided to tear it down and the rings look okay visually. No stuck valves. Put it back together and no change.

I may be leaving out something but if anybody has any thoughts on what the best direction to go in is I would appreciate it greatly. I don't really have the money to start replacing parts with the hope that it fixes it.
 
Sounds like your petcock has failed and raw fuel is backfeeding down the vacuum line and into the #2 carb...and subsequently the crankcase. Either that or someone left the petcock in the Prime position.

Best to check the petcock and maybe the carbs too. If the float is stuck on one or more carbs, they will over flow and flood the engine with gas.

Tearing down the engine was a drastic action. Did you replace all the gaskets with new original equipment Suzuki gaskets when you did this?
 
Thanks for the quick reply, I'll admit not the head gasket but it was a calculated risk and I'll hope for the best. It may seem drastic but once I had the valve cover off checking the clearance it proved too tempting to want to take a look at the rings.
So would this explain the oil leak as well? The petcock doesn't have/never had a lever on it to turn to prime and I'm planning to replace it eventually but it doesn't leak and fuel flows freely only if I put suction on the vacuum hose. So assuming I can rule that out. Would that or the float being stuck explain the oil? What I'm puzzled about is that the oil leaking around the #2 header is not mixed with gas and I don't have any indication that there is gas in the crank case.

I'll try to be mores specific. When I first start it there will be some gas leaking from the muffler header joint. As it warms up that mostly stops and the exhaust starts to get smoky. Then you will start to notice oil on the engine below the header. And of course the #2 header stays cool.
 
Very drastic indeed. You might have gotten away with re torque to specs on your engine bolts first off. I'd say replace the head and base gaskets. Your base may be ok now but it will be a damn shame for it to start leaking on after you put everything back up and together. Get to it while the heads are off.
Where on the motor is the leak exactly? There are two rubber O-rings on the mount bolts that can cause leaks just off the very front of the case where the inverted head bolt is.
 
Best to tear the engine down now and replace both the head and base gaskets. This will save you from having to retrieve the bike later when the head gasket pukes. As mentioned already, OEM Suzuki gaskets are the way to go if you care about reliability. Oh, and replacing the valve stem seals is highly recommended while the engine is apart.

You may want to try a clear tube on the vacuum line to see if there is gas flowing down backwards into the engine. That model petcock doesn't have a lever, and the service manual explains how the prime feature works. Bad news is those petcocks are the worst in the GS family, good news is they are cheap.

I have no idea what's going on with the oil leak other than maybe the valve cover and/or the head gasket is leaking.

When gas dumps into the cylinder and crankcase that thins the oil and increases the level. You might want to check that.

Good luck
 
It sounds as if you're confusing the head gasket with the valve cover gasket, which did you change?

How did you verify that there is no gas in the oil?

If you have gas coming out of the exhaust port, you have a serious problem

Oil leaks from the valve cover are a common problem
 
Thanks for all of the help guys. Engine is back together now so I'd have to tear it back down to do anything else to it. Sorry if my gasket answer was confusing. I replaced the valve cover gasket only. I had a replacement valve cover gasket from the previous owner. Everything was torqued to specs and the rubber o rings around the mounting bolts are in good shape and seated properly. I considered replacing the valve stem seals and assuming I have to tear it back down again I will definitely replace them along with the rest of the gaskets.

The leak is definitely from the #2 exhaust port. I have cleaned and rechecked several times. I can't definitively say that there is no gas in the oil. I changed it not too long before the problem started and in the process of tearing apart and putting the engine back to together I drained and refilled the oil. If there was gas in the oil it wasn't enough to smell or feel. However I didn't run a ton of gas through it so I guess it's possible.

I'll try the clear tube on the vacuum line. That will at least rule it out.

Thanks for the heads up about the petcock. I'm surprised I didn't catch that in the manual.

What has me stumped is the oil. I can live with it being a serious problem. But I hate to start replacing things and then put it back together and it not be fixed.
 
I am with Mr. Nessism on gaskets!!!!- I wasted 24$ on a silicone valve gasket.
Was like a water pik- spraying oil everyway!
 
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