I'm not up on all the new higher performance light weight 4 stroke dirt bikes and if yours is a similar design to the Hondas, but I'll relate the following.
A few years ago, one of my teenage neighbors, had a very low strung, mild tuned Yamaha 200? dirt bike that ran well no problems;
He replaced it with a higher strung Honda 250 CFRX?, it was much higher performance and almost immediately he started to have trouble starting it.
He spoke to me about it and I researched it at the time and learned that, poor starting indicated a need for valve adjustment.
He had a repair shop adjust the valves and it started and ran excellent,,, for a couple of weeks,,, then back to poor starting.
When I researched it on line, people in the know indicated that when the valves needed constant adjustment, it was an indication that the valves were stretching and getting ready to self destruct.
Options were to replace the stretching valves or flog the bike,,, the kid made a wise choice and got rid of the high strung bike, replacing it with a milder tuned trail bike.
I'd be checking out some of the forums dedicated to your bike, but I think most of the new high strung 4 strokes can be hard on valves and I think one of the recommended fixes is replacement with Kibblewhite? sp?
Good luck with it
Kelly
