I'm currently working on a 2000 Suzuki Quadrunner 300F 4x4 and when I was contacted to work on this machine I found the crankcase to be overfilled with gasoline in the oil. Not a good thing I know, the question I have is after I have drained the oil and changed it twice, cleaned the airfilter because when the oil is mixed with the gas it loses it's viscosity causing it to be pumped out of the crankcase into the airbox. I also cleaned the carburator, thinking that the owner leaving the gas pitcock on may contribute to the float sticking letting gas continuaslly flow into the crankcase. I know that there is a slight possibility that the rings are washed out. The question that I have is after this work, why may I still be getting gas in the crankcase? Why is the bike still smoking while it is being ridden? The machine runs fine without a hesitation, just smokes and gets gas in the oil. Any assistance with this problem would be greatly appriciated. Thanks, Bigg

 

I would assume the carb is still overflowing, faster than it can drain out the overflow, and it is dumping into the intake when the engine is off... It will eventually seep past the rings into the crankcase.

Float, needle and seat, along with float level would be suspect. If the carb has a primer ****, often a failed seal there can dump gas, too.

If the bike is smoking, it may be from running rich, or if it is blue and smells of oil the rings (and possibly piston and cylinder) may already be damaged.

 

Yeah, I have a Honda Rancher 350 4x4. It keeps getting gas in the oil. I put a new carb on it and have changed the oil 4 times now and after a day of riding it has gas back in oil. I als o put a new petcock on it and the bike doesn't smoke a bit. I don't know what else it could be, but it does make loud knocking noise in bottom of motor every so often once it gets gas in the engine. Runs great for about the first hour then gas is back and makes the noise. Any help/ideas!!! Thanks, Chad

 

As far as the Rancher & Suzuki,be sure your fuel tank vent lines are not plugged with mud or dirt dobbers,a plugged vent will cause vapor build up that overides the needle & seat causing fuel to enter into your intake.If the vent tube is clear check your float levels.I would reccommend pulling the carb,with the Honda it can be done with out cutting loose the choke/throttle cables,pull off the bowl and see if your float is level with the carb flipped upside down,if it's not bend the tang to acheive this,if it is level pull the pin that holds the float in place with needle nose pliers,careful not to drop the needle and check the needle tip,the rubber tip should have no grooves and should be somewhat flexy.<IMO> I'd pick up a needle and replace it prior to the teardown.On the Rancher if it runs rich,idles up & down or rather erratic check your choke plunger,they tend to go bad often and cause it to run rich.Gas in oil=extensive DAMAGE over a course of time.Even a NEW carburetor can have a float out of adjustment.Turn your petcock to OFF when not in use