4 stroke gas getting inot oil?

CRP

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Jan 7, 2017
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Not sure why this happened but some how a lot of gas got into my oil. I changed the oil and watching it carefully but something must be wrong but I don't know what it is?

Temps have gotten much hotter over the last few weeks and I hadn't run the bike for a couple of weeks. Is there some how the gas could be coming from the tank down into the carb and continue on into the engine? I don't turn the fuel valve off when I park the bike, should I be doing that?

When I took the oil filler cap out oil and gas spilled out everywhere, the crank case was full.

I'm kind of baffled on this?
 

Tony01

Well-Known Member
Nov 28, 2012
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what oil are you using? And what are the temps you ride in? Sometimes if you use too light an oil it will cause blow-by because of the higher summer temps, and the oil loses its viscosity. . But a lot of gas in oil is very bad.
 

Slogger

Member
Sep 8, 2014
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nohio
Yup, turn it off. Old time bikers always turned off the gas if the bike is to be parked for long. If a tiny bit of sand or grit gets into the float needle's seat, it won't stop the gas and will flood the engine.
That's what I'd check first.
Newer motorcycles have vacuum operated petcocks, but I shut em off if there's a lever.
 
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What Slogger says is right or the float is stuck open. Make sure you have a fuel filter inline with the gas tank and carburetor as this will stop small particles from entering your carburetor and causing this problem. You could also have a sunk float. This caused by a hole in the float allowing it to fill with fuel and not float. You will probably have to remove the float bowl and check for these problems.
 
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CRP

Member
Jan 7, 2017
57
5
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SC
Re: 4 stroke gas getting into oil?

Didn't get a chance today but I'm going to take the carb off and see if there is dirt in there. I have an inline fuel filter BTW. I bought the bike used so I have no idea what has happened to it along the way. I'll clean the jets while I'm it and all that.

I'm using 10w30 in the bike right now and temps are in the 80's, a few days ago it was 95 degrees in the afternoon.

I did notice some gas on the air filter so maybe the float is stuck?
 

CRP

Member
Jan 7, 2017
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SC
Took apart the carb and cleaned it all, no noticeable problems. Float seemed to be working right but the bottom of the bowl did have a little grit. Cleaned it all.

The air filter case and filter smelled like gas has been shot backwards out of the carb.

This is odd or I don't know how this works. There is a tube from the crankcase to the air filter housing but there is no hole in the housing for air to get or out of that tube? Is that supposed to be like that and if so why? I would assume that should feed gases back up unto the intake to be burned? Other then that I have no idea why there would be a tube there?

Fired the bike up and I still have to use a tiny bit of choke to make it run right. Stared right up but I have to have the choke on some like a couple of millimeters on for the engine to run with power. If I don't do that the engine seems to run rich and will bog down on acceleration. Don't know if this has something to do with whatever is going on.

Tomorrow off for a few mile test drive and see what happens.