2006 Kawasaki Prairie sputtering when hot

[coupedehille]

I have an '06 Kawasaki Prairie 360 4x4. Three snorkels, 1 for intake and 2 for cvt. The bike runs great until the engine gets hot and then it wants to sputter when I give it gas at low RPM's. I just had the carb cleaned and adjusted. They fixed an idling problem and a misfiring problem. But still the same issue with sputtering when it's hot. If I remove the lid on the air box it actually cures the problem, so I thought at first there wasn't enough air in the mixture, but I have since tried to adjust the mixture and it will not adjust out the problem when it's hot. All that does is make it run bad the rest of the time when it's not hot. 2 1/2 turns out seems to be the best mixture, which is where they had it, so I put it back there. It runs great when it's cold, so I don't think mixture is the cause. If I hose the carburetor with cold water the problem goes away too.

Vapor lock seems more likely the cause of what I'm experiencing. I need some tips on what works if anyone has had this problem and solved it. I fabricated a barrier between the carb and the engine and wrapped the exhaust with header wrap and the problem is less severe. I run the highest octane gas available, have not tried adding octane boost, but I read that it also helps. How about the carb heater? Should I disconnect the leads to that? I live in FL so I rarely have to worry about cold. Might try a small 2-5 psi electric fuel pump to keep the fuel pressurized all the way to the carb, that is supposed to work. This weekend I'm going to mimic a 3 psi pump and see if that will cure it. I have tried removing the fuel cap, that doesn't make a difference.

It happens long before my fuel tank gets hot. The gas inside is not bubbling. after 10 minutes of hard riding it's hot enough to start sputtering. hose the carb for 3 seconds and it's fine. why do I always have these f'd up problems? lol

I appreciate any tips.

Thanks.

Mike

[Ajmboy]

I don't know how we missed this one. How did you make out?

[coupedehille]

I haven't been riding lately and have let it go for a while. since spraying water on the carb helped I built a barrier between the carb and motor using roofing metal. that cut down on the problem significantly. I added octane boost for the last ride and the problem went away except for about 1% of the time. Tomorrow I am getting the valves checked and adjusted, since the exhaust valves being tight is a known problem on the prairies. I don't think it was vapor lock, and a know it's not the mixture. Hopefully the valve job will fix the problem. I won't ride again until november, so I really won't know until I burn the fuel with octane out and refuel with regular and get the bike hot. I'll post back after the next ride with the results.

[Ajmboy]

I haven't been riding lately and have let it go for a while. since spraying water on the carb helped I built a barrier between the carb and motor using roofing metal. that cut down on the problem significantly. I added octane boost for the last ride and the problem went away except for about 1% of the time. Tomorrow I am getting the valves checked and adjusted, since the exhaust valves being tight is a known problem on the prairies. I don't think it was vapor lock, and a know it's not the mixture. Hopefully the valve job will fix the problem. I won't ride again until november, so I really won't know until I burn the fuel with octane out and refuel with regular and get the bike hot. I'll post back after the next ride with the results.

Great, keep us updated. Good luck with it.

[coupedehille]

I got the valves adjusted saturday. the guy only charged me $20 and I gave him a $10 tip. he said there definitely was some leakage getting by. it fires right up now without touching the throttle, the way it should. I used to have to floor it to start it. I won't know until I ride it next month whether or not this cured the sputtering problem. but the mechanic thinks it should have, and I'm hopeful now.