I have a 99 Honda recon. Just a few weeks ago I got the top end rebuilt because the motor was smoking pretty bad. I just took it out to the mx park today, and after a couple hours of riding, it started to misfire as I got hard on the throttle and going up hills. I checked the gas, and the spark plug, but seemed ok. Opened my airbox, and the crankcase vent appeared to have been blowing some kind of thin liquid back out into the air filter. It smelled like stale gas. When I unscrewed the oil dipstick I also noticed the smell of stale gas, and the oil seemed thinner than usual. The oil only has about 10 hours, and isn't dirty yet. Before my motor was rebuilt I also noticed the same smell, but figured it was just old oil. Any ideas on how gas could get into the oil, possibly from jetting? Also, could this have caused my motor to start wearing out rapidly the first time? thanks

 

the only time i've heard of this happening is when the petcock is on and the float level gets stuck open.

 

Did you transport the bike with the petcock on??? If so, the float bounces up and down and overfills the bowl. Then it flows into the combustion chamber, past the rings, and down into the crankcase.

 

if the petcock is the fuel shutoff, then yes I transport it with the valve on. If I transport it with the valve off I won't have this problem then? thanks

 

there is your solution...simple huh?

 

I understand completely how the gas is getting into my oil now, but would that be a reason for the quad to misfire when I get on the throttle hard? It acts like it does when it's low on fuel.

 

anyone?

 

When ever the motor isnt runing, turn that gas valve to off. This is the only sure fix..you could replace the needle valve and seat, but theres no garuntee that it wont happen again.
The gas washes the oil off of the rings and cylinder wall, and this will eventually trash this motor. Its most likely what happened to it the first time.
Do an oil and filter change, you dont want to run it with gasoline dilluted oil.
After the oil change, pull the spark plug out, and dribble some oil in the hole, 1/2 teaspoon should be good. Then pull the motor over, with the rope, wih out the spark plug in. Do this for about 5 pulls. This will put oil back on the cylinder walls, and the rings.
If the plug looks bad, get another one, and put it back in and start it up.
If it still misses bad, do a compression check, and if that looks ok, then its a carb issue.