[toogood114]

so i have a crf 450r motor in a 400ex modified frame for a hybrid quad and i bought it non running. pretty much it has hotcams,full hinson clutch, je piston, and a tc racing straightpipe kinda exhaust. i had to replace the crank in it and i also did all the gaskets and seals in the motor. everything is in time the only problem i know it has is that the valves are loose becuase i guessed on the valve shim sizes.they are about double as loose as they should be. i think it has a 45 pilot jet and maybe a 178 main in the carb. i cant for the life of me get it to start from the kicker cold only starts cold by pulling it with a truck but it runs great when its hot and sometimes fires up from the kicker when hot. i took it riding last weekend and i thought i blew the motor because i was 4th gear wide open and it randomly died and refused to restart, i still dont know why but when i took the motor apart again everything looked fine. i cleaned everyhing up inside and honed the cylinder too. i didnt replace the rings on the piston though. if someone can help it will be greatly appreciated.

[crfsonly]

welcome to CRF's Only! the valve clearance must be correct for the motor to start as designed. first correctly set the valve clearance and report back with the results.

odd to me that you are able to take the motor apart but don't correctly set the valve clearance. also, if you honed your cylinder by hand you have likely ruined your cylinder. doing it right requires the right equipment and knowledge. when honed correctly new rings should be used.

ken