Gas in Oil please help!

[kerschey]

I went to change my oil and there was gas in it could someone please help?

[bigbike-r]

yes - drain it -
could be your diaphragm has gone in the tap

[scottynoface]

Has the bike fallen over?

[kerschey]

I did drain it how would i go about fixing it so it won't do it again?

yes it did once for like a minute!

[bigbike-r]

how much fuel we talking - could you see it sitting on top through the oil view window- take the fuel line off the tap is it flowing - it shouldnt be whilst the engine is off unlesss its on prime - if it is then theres a problem with the diaphragm and this will just carry on filling the bowls - could be a stuck float this should just drain through the overflow but can fill in the cylinder and find its way down the pistons and into the oil

[Kfreak]

The only way you will get gas in the oil is if you have a float needle stick open. You need to check them.

[tic]

It's not the only way. A bad petcock will allow gas into the crankcase

[maniac1886]

^^^^ Haha 6 years later...

[shpielers]

It's not the only way. A bad petcock will allow gas into the crankcase

Incorrect. A bad petcock will let fuel through to the carbs instead of closing off. The fuel will only get through the carbs and into the crankcase if the floats are somehow screwed up (heights set wrong, bad oring not sealing, debris keeping it stuck open etc)

So a bad petcock definitely needs addressing. But if your carbs are in correct working order, a leaky petcock will not be able to pass fuel through them to the crankcase.

[tic]

Well, a bad petcock can set up a situation where fuel gets in the crankcase.. I guess that's what I should have said as obviously gas must go through carbs to get to engine.

[shpielers]

Wasnt intending on busting your chops. Everyone's a newb at some point, so I generally try to be as specific as possible in case someone who isn't knowledgeable comes across it.

[tic]

NP.... I'm here to learn and I appreciate the correction. I don't intentionally post bad information but finding this website is cool and has me posting a lot. I need to tone it down a notch.

[Bettyswolloks]

So how is the petrol actually getting into the oil?

"A bad petcock will let fuel through to the carbs instead of closing off"

How does it get from the carbs to the crankcase? If petrol is coming out of the overflow it will just drip out onto the crankcase underneath the carbs.
Or is it going through the main jet past the needle?

[maniac1886]

If the petcock doesn't stop the fuel, a functioning carburetor should stop it. Fuel flows down the hoses and fills tha carb bowls. There is a mechanism in the carbs that closes off the fuel inlet by using a "float" when the fuel level rises, the float moves to the top and the float needles close the reservoir. The problem is you can get debris in there from the tank and it will prevent the needles from seating correctly and sealing. When that happens the fuel level in the bowls continues to rise until it overflows the emulsion tubes (where needles sit) and then drains into the head. While it's sitting in the head, it will eventually drip down around the valves and into the combustion chamber, passed the pistons and into the case. Should you try to crank it in this situation the head literally gulps mouthfulls of fuel every time the valves open. Then you have 4 gallons of gas mixed with 4 quarts of oil in your crankcase.

[tic]

Good explanation, thanks. I keep wondering when my 23 year old big kat will have a big problem. It's cherry now but it's never had the carbs apart or the engine. It's using a quart of oil every 2,500mi. now so I know it needs some attention but it still starts easily and runs good. I think I'm on borrowed time with 72,000mi.; especially after browsing these forums. I actually planned to keep it for many more years but now I'm not so sure. A total rebuild is waaaay over my head