Kdx200 hesitates at high rpm after riding for a while

[CRX200_FRANKENSTEIN]

2001 kdx200, bike starts first kick and idles with no issues.

First hour or less of riding and bike has no issues, gets on powerband and runs crisp. Get back to staging area and rest for 30 mins or less, go out on the trails again with bike slightly warm and it hesitates badly at high rpm. Noticed it going up same hill on both occasions.

Happened last two rides. Previous ride I changed trans oil and it happened again this week.

What could cause this hesitation which happens only after bike is warm and has been out for a while.

Compression is good, carb cleaned before and jetted to factory spec. Ride at sea level.

I've seen similar posts but nothing for when bike is warm and rode crisp less than 30 mins before

Thanks in advance

[firsthere]

Occasionally mine runs a little different after a session of full throttle runs. Only thing I can attribute it to is the increased heat causing the power valve to stick. I know the power valve was sticking after the last rebuild due to the mechanical paw binding on the actuator shaft (the one with the left hand thread nut). It ran bad at low RPM's due to the PV being stuck full open.

Moral of the story, check to see it the PV rotates freely by rotating the 10mm nut behind the round (Flat Blade) plug on the leftside of the cylinder when its having this problem.

[CRX200_FRANKENSTEIN]

Thanks for the response. I'll be checking the powevalve this weekend.

A buddy hinted at the reeds but I wasn't too sure since bike runs crisp for the 1st hour of riding

[bufftester]

Lots of possibilities without much more info. First thing is make sure your fuel flow is good and eliminate any obstructions in the tank/filter/petcock. Then I'd try to isolate it further by riding then waiting until the engine is fully cool before riding again and see if it makes a difference. Make sure your cooling system is functioning correctly. Could also be a breakdown of the ignition coil at temp. Its either fuel or spark.

[Goofaroo]

These intermittent issues can be tricky to track down sometimes. One thing you might check is the spark plug cap. Unscrew it from the plug wire and you might find that the wire is badly corroded. Take a pair of dykes and clip the wire back about a quarter inch. Clean inside the cap as well as you can and carefully thread it back on. It might give the cap a better purchase on your wire and solve your issue. If the cap is badly corroded you can pick up a new NGK cap at Autozone or a bike shop. It’s worth a shot before you start suspecting the coil.

I do a lot of adventure riding and have managed to get a few guys back on the trail with this simple trick. I hope it fixes your issue but if not it will at least eliminate one possible cause.