This problem started last year, but was very random, and not easily reproduced. This year the problem is worsening, is more easily reproduced, and I can't quite figure it out. When I am riding up a fairly steep, but well groomed hill, if I push the bike passed half throttle, it will ride fine for a short time, then start cutting out, then finally just shut off. Just like someone turns the fuel off. I have to wait about 5-10 mins to even get it to fire back up. It acts like there is absolutely zero fuel in the carb. I haven't torn it apart just yet, as I'm not sure what to look for. I would think that if the needle valve was sticking, it would fill up the bowl quite quickly and start up after a few seconds. So I think I've ruled that out. I would think if one of the jets were bad or dirty, I'd notice a much different type of performance, but she still starts and runs just fine on all terrains but the long hills. I've read/heard that one of the diaphragms in the carb might be suspect, but once again, I'd like some input before I start dropping money on parts that do not need to be replaced.

I've done the usual checking...good fuel, clean (and non-fouled) plug, a clean air filter, etc. Doesn't blow black smoke from a rich mixture. Only will backfire when it shuts off going up the hill.

FWIW I have a friend who has a 97 KQ and for some reason thought the choke lever needed to be down...ran really rich, fouled plugs, wasted fuel, but his had the same symptoms when going up the hills. I simply corrected his error and readjusted his idle screw, and his problems went away.

Any help would be greatly appreciated.

 

Sticking float. Do a simple bottom end carb clean-out and I bet you'll fix it.

 

That is high on my list of culprits. Thanks.

I stopped by the dealership and picked on one of the mechanics. He said it might be a clogged/dirty fuel pump, or perhaps a bad gas cap. Apparently the vent can occasionally fail, creating a vacuum in the tank, and not allowing fuel down the lines. Gonna give her heck and see what I can find out.

 

My old KQ had a pinched vent line off the fuel cap - but it just generally ran crappy, wasn't limited to when it was climbing hills. Still, easy to check that one.