My 2000 Bear Tracker 250 has extremely low hrs.. It starts and runs perfectly until it warms up . Then it starts cutting-out, running a little with the choke pulled out. Then it quits and won't start back until it cools off. It will repeat this cycle over and over. Since it starts and runs so good, I think I can eliminate carb (trash) problems. I don't know beans about the electrical stuff! Help----please Also, ROLL TIDE!

 

welcome to the forum! did you ever have the valves adjusted? that could be a problem. mabe a burnt valve, but if its new thats unlikely

 

No, haven't adjusted the valves. It's like new and starts and runs so good, I didn't think it had valve problems. Thanks for the suggestion---if you can think of other things to try, please advise. There's a shade-tree 4-wheeler mechanic nearby . I will probably take it to him if no body in the forum has had this problem resolved.

 

it could be a valve problem, or possibly an electrical. if the coil heats up the cdi could misfire, makeing it a heat lerated problem.

 

Thanks,
I had thought about a bad coil. However, I don't really know enough about this kind of problem to think ! Will ask the shade-tree man to check valves, coils and whatever a"cdi" is. Thanks for your input.

 

it could be a wire that is broken and making a connection when the insulation is cool and tight. when it warms up, the insulation loosens, and could be making the connection go intermittent.

just a suggestion. hope you get it figured out. i would start by checking all the wires along the frame and near the exhaust pipe or any other source of heat.

 

Thanks C-dude,
Didn't think about wiring short. I did add a horn wire . Will tell the s-tree man to look for shortages.

 

What about the choke? Does it run longer with the choke on or off? Is it possible that the choke cable is loose and stuck in the on position?

 

T-dad, The choke is a push-pull type mounted directly on the carb. It works good. Someone said they had a similar problem and after giving up a couple times, finally found a vapor lock problem. The shade-tree man is looking at several electrical things ,trying to find the culprit. Surely this problem isn't unique to a Yamahopper ! Thanks for your input !

 

Ok, my thought was that if the carb was still choked it would not run well when warmed up. Does it have to get HOT before the problem happens? I would think to have a vapor lock problem you would need to be riding for some time to get it hot enough to cause that, unless something had been done to the quad to change it from stock. If the electrical things don't pan out it wouldn't hurt to look into the carb as you turn the choke on and off to be sure that it is really moving.