when i start my 86 trx 250 i hear a loud ticking noise coming from the engine it is not always there but when the engine is cold it is really noticable and is very worrying as the engine gets warmer the ticking fades or during acceloration the ticking fades what could this be? my dad thinks it could be piston slap but i just wanted to double check with you guys to be sure.
thanx in advance
mike

 

sounds like valve clearance is incorrectly adjusted. Try listening to the engine with a screw driver placing it over the valve covers and other various parts of the engine to see where the sound is the loudest. Then post back.

 

I believe it was the valves it wouldn't stop ticking. Sounds like its got a Wiseco piston. My quadsport did that until it warmed up. The mechanic said its normal for that piston. If it hasn't ever been rebuilt then it prolly needs to be bored and a new piston.

 

try adjusting the timing chain tensioner when it is idling.