I race a sweet 250RX stroker, with full mx chassis and all the goods, but when I first crank the bike up it blows smoke out, and also when I get on it hard, It has a fresh top end so I know it has to be a valve, how much will the valve guids cost, and what labor is there to consider?
PS: If you dont know its a 250X motor in a 250R chassis

 

Still sounds like rings to me, valves only produce a quick burst of smoke but if it is a valve it is probley just a dry old valve seal. I would also throw guides in while i was in there and do a 5 angle valve grind. pretty easy and under $100 to do it yourelf including the shops grinding and all parts. Grab a climber manual and have fun. Use a socket to get the springs off, just tap the socket with a hammer when holding it on top of the springs. Around a day to do the job.

 

Thanks for the input, Its a quick burst like inbetween gears when you are on it hard, I know someone that does valve jobs on cars all the time and I am hopeing he can help me out, anyone know how much the guide and seal cost?