86 200x wont start when warm

[Husky250]

I have an 86 200x that I have sunk waaay too much money into. Whole rear is off a 300ex, the rod was bent so had to get a new one build and the crank machined to fit/ new piston rings yada yada yada. It starts like a champ no matter the temp with zero choke. it runs simply awesome, a true grin maker everytime. I come from a trials background and LOVE logs, the bigger the better. If I happen to stall it simply wont restart. it has maybe 10 to 15 rides all about 20 minutes long on the motor. anyone have any clue why this thing will not start when its warm? I remember the Yamaha 426 back in the late 90's and early 2000's wouldn't start once stalled. I am a 2 stroke guy so I am clueless. Any input guys..... thanks!!!!

[fabiodriven]

I had a four stroke do that because the valves were adjusted too tight.

[350for350]

It may not be related to this problem, but you said that it doesn't need the choke to start in any temperature. It sounds to me like it may be running rich.

[christph]

Second on the valve clearance. If you don't have enough clearance between the rocker and the valve, the heat can cause the valves to open slightly (due to the expanding metal) and so you lose compression. This also means your performance should drop off as the engine heats up.

[Husky250]

Thanks all. Work has prevented me from checking up on this. Will have to mess with the carb cause it doesnt seem to loose any performance at all as it warms up.

[fabiodriven]

I'd still check the valves.

[Husky250]

Thanks Fabio... I soooooo am not a 4 stroke guy!

[yaegerb]

It's either valves, electrical or leaking head/base gasket.

[Dirtcrasher]

^X2 - Electrical (coil), too tight valve lash, low compression and too rich or lean jetting are all possibilities.

[Husky250]

Thanks all you guys Rock!!!!! now anyone know where I can race this thing in NE Ohio... Well other than Pine lake. (off road guy not a tt rider)

[Dirtcrasher]

Seems like the guys hit Breezewood quite a bit.

Or Paradise for flat tracking...