Does any one know, what size a stock piston is from a 1987 trx250x? I dont have a manual yet and still need to rip it out, but it does say "HCO" and "IN" on top of it, not sure if that means anything. Can someone help me out so i can get it ordered?lol

 

74mm

 

book says 73.965-73.985 (2.9118-2.9128

 

Thanks im rebilding my 250x from the fram up so i will have some more questions for ya at some point, thanks

 

The side it says in on you put that towards the intake side (rear) of the engine.