Petrol in the oil.

[Guest]

I have just drained the oil out of the old girl.
There was a strong smell of petrol in the oil.
I think this is from a stuck float valve, poorly seated float valve or the floats not set right.
Is there something else that could cause it?

My main question is how long will the petrol smell stay in the oil?

I cleaned the carbs and set the floats a wee while ago and every thing seemed ok.
You think I need to take them off and do then again?
Cheers

[tone]

A couple of thoughts .... it may well have been caused by a stuck float or 2 but it could be incorrect float heights, even so if theres a lot of fuel in the oil i'd check the fuel tap is shutting off properly ! a favourite gs problem :-D

leaving the bike on the sidestand wont help either as a small amount of fuel tends to drain down to the lowest carb & wash the bore especially if the float is not shutting off

last thought is it running a little rich & bore washing in use

[Dave8338]

Do you have the vacuum operated petcock? :shock: If so, that would be worth looking into. :?

[ericzx7]

I had the same problem with my 85 700E. Was a combination of a little gunk keeping a needle frome seating, and a faulty petcock. My petcock is vaccume operated, so no off position. carbs clean and petcock replaced, no problems as of yet.

[KiwiGS]

last thought is it running a little rich & bore washing in use

I haven't had the bike running long enough to wash the bore.
But I would be surprised if it had been running rich, every thing is stock except for a 4-1 (which if anything would cause it to be a bit lean. Yes?)

Do you have the vacuum operated petcock? :shock: If so, that would be worth looking into. :?

It does have a vac petcock which I have tested and found to be in perfect working order.
But I will check it again just to be on the safe side.

I am just not sure how long the gas has been in the oil.
The bike spent a year or two living under a tree on it's side stand with gas in it's tank

[tone]

But I would be surprised if it had been running rich, every thing is stock except for a 4-1 (which if anything would cause it to be a bit lean. Yes?)

Thats how it usually goes mate...... but not always, i found this out on the last bandit i owned a bolt on race can made it run rich as hell & had me chasing my tail for days till i sussed it

still my best guess given the extra info is that either the carbs are bunged up, floats are set wrong or the fuel tap is faulty the only other thing i can think of is stuck rings, (compression test, leak down test ??)

[KiwiGS]

Well it looks like I will be pulling the carbs down again.\\/

Tone I ran a compression test on the bike when I got it home and it was all good, 120psi across all 4 pots (cold).
Haven't done a leak down yet.
I made the muffler myself and I dont think it could be described as a race can.
Unless Rossi and co are using stainless drain pipe for the mufflers now.:-D
Cheers

[fnickel]

I would suspect the vacuum petcock. It may be periodically malfunctioning, even though it checked out OK when you tested it. Thats what happened to my '80 GS1100L. I noticed it overnight, the clutch went out of adjustment and my oil level suddenly was overfull. And yes, the oil smelled strongly like gasoline. If your petcock was working properly, then it shouldn't matter much if your floats were leaking, because the petcock would shut off the fuel when parked. Mine was allowing the vacuum line to the petcock to drain fuel back into the intake system and into the engine. An oil change should cure the problem in the crankcase, as long as you stop it from doing it again!

[Greenagain]

I think if you leave the petcock on PRIME it let's fuel run through it.
I recently picked up a GS1100 that had been sitting a few years, and I drained about 2 gallons out of the crankcase.

[Wire Wheel Katman]

As has been suggested, check that fuel isn't leaking past a split diaphragm in the fuel tap. As has also been said, don't leave the bike for any length of time with the tap in the Prime position as the weight of a full tank of gas can overcome the needle valve's ability to shut the fuel supply off.

[psyguy]

i would double check and triple check the fuel tap before disasembling the carbs
the fuel tap on "on" or "res" should not let ANY fuel so even if your floats are buggered there should be no leaks