My KFX has about 6 hours on it and has started to foul up recently. It is hard to start at times, but once it starts it is usually easy to restart, except after about 45 min of riding. Around 45 min out, it starts to backfire/ pop and starts missing and eventually stalls. At that point it won't restart.

I have already pulled the plug and cleaned it. I have cleaned the air filter. I have confirmed that the carb is getting fuel and the ignition system checks out.

Any thoughts or ideas?

Thanks

 

i Know when i first got my KFX, i would be riding across an open field in a high gear, and if i pulled the clutch in and let off the gas, it would just die. I've prbally got 15hr's on it now, and it's getting better. Mine is however hard to start to sometimes, but it got better too. if u read in the owners manual, it has a section that explains that if the bike is hard to start, "cold natured", it says to run a different plug. I still have the stock plug. it's in the manual somewhere. The only complaint i still have about mine is it idle's funny sometimes, and if it's a an idle, and i blip the throttle it dies. i've been told that my carb needed adjusting, but i haven't gotten around to getting it to the dealer.

As for the 45min backfireing, poping, i don't know. the only thing that i can think of is maybe check the gas venting line on the gas cap. it may be kinked causing suction and it stops getting gas.
Just get atleast 10-15hr's on it before u start messing with too much stuff. I know that mine runs better everytime i ride it.

 

Yea, I read that thing about "break-in" and thats what I did, have never had problems starting it except when it was -5 outside. then it coughed and choked a little, back fired once (shot a really cool flame out) but it started and idled, just had some bad gas i guess lol.