Petrol in engine oil.

[sconz]

Hi,

my 1980 GS1000S has been sitting up a while and this is the second time I've had this problem. I am getting a small oil leak from the clutch engine case. On opening the cover the oil stinks of petrol and is very thin. Thankfully the gasket sealer on the engine case isn't petrol resistant and it has pointed this out to me.
The bike has been sitting in the garage with absolutely no miles being put on it, it is started from time to time, warmed up and that's all. Would it be safe to think that the petrol is getting into the barrell from the carbs as I'm sure I've left the tap on prime from time to time. I would prime the carbs if I hadn't started the bike in a while. Is it just gravity or have I a stuck float or valve in the carbs. Would it be worthwhile to take them off and clean them out. I also realise that I shouldn't leave the bike lying up with the tap on prime. The petrol would seep down the barrells and into the engine?
As the bike is stationary, surely nothing more sinister could be at work, could it?
Any thoughts?

Sconz.

[chef1366]

Get a new petcock or clean and rebuild the carbs with new o-rings.
Three ways the fuel can get in the motor.
Bad o-rings on the inlet valve
Bad petcock
Dirty and/or worn float needle and seat.

[rideOn]

yes, check the petcock. this issue made me a real believer in this forum. gas started blowing out the muffler. i called several dealers and i got the same answer: "i don't know, bring it in." yes, they knew, just wanted my $75/hr.

i found this forum looking for the answer. i have not replaced the petcock yet, but want to. for now, i took the vacuum line off the engine, capped the hole at the engine and stuck a screw in the vacuum line. for now, just a manual operation. if you have gas in the oil, change the oil ASAP!

i got lucky that there was no damage. it smoked for a few minutes after these corrections, straightened out and not an issue.

[Steve]

All of the above, and don't start the engine to warm it up from time to time.

Although it may sound like a good idea, you don't really get it properly warm, especially the exhaust system. All you are doing is creating condensation in the oil and exhaust. This is no good for the oil and helps promote the exhaust system rusting from the inside out.

.

[mighty13d]

All of the above, and don't start the engine to warm it up from time to time.

.

Just for that I'm going to go start my bike and let it warm up for 2 min and shut it it!! lmao


Ok ok, I will take it for a ride if I do that.

[sconz]

Thanks.

Thanks guys, I have the oil drained and I'm just about to replace the engine case. I'll take the carbs off and give them an overhaul and clean out.
Just wanted to ask rideOn, if I disconnect the vaccuum pipe, will the carbs still draw the petrol into the chamber ok? I will try your fix but I don't fully understand how that works.
Also if the petcock is in the on position, then theoretically petrol shouldn't be drawin into the carbs when the bike isn't running. Should I try it with it turned on (not un my usual prime position) or even disconnect the fuel hose from the tank when the bike isn't being ridden.
Again thanks for taking the time to reply.

Sconz.
1980 GS1000S
1977 GS750DB
2008 GSX1400FE (I've gone to the dark side)

[rideOn]

Just wanted to ask rideOn, if I disconnect the vaccuum pipe, will the carbs still draw the petrol into the chamber ok? I will try your fix but I don't fully understand how that works.

Sconz.
1980 GS1000S
1977 GS750DB
2008 GSX1400FE (I've gone to the dark side)

i got this same answer somewhere else in the forum and mine has worked fine. when i do replace with a new one, i'll probably go back with a manual. i'm used to it. the petcock is now manual operation. thr fuel is gravity fed into the carbs, so it's good.

down for off and back for on. i think reserve is forward. not sure on that because i try to stop often to top off. my gas gauge works wierd so i try to keeper er full.

[DanTheMan]

I have the original petcock on mine, it has only two positions; ON and Prime (some also have RES). It's operated with a screwdriver. Unless your petcock continually fills your carbs in any position, than just leaving it in the ON position with the vacuum line still hooked up it should be fine. To test it, put in the ON position, un hook the fuel feed and see if gas comes out. Then suck on the vacuum hose, gas should come out. As soon as the vacuum is removed, the fuel flow should stop. Put it on prime and gas should flow freely. If that's the way it is working there is nothing wrong with the petcock.