hello all!! i just picked up a 2000 yamaha blaster from my buddy. he put the 240 big bore kit in it and he kept complaining how it didnt run. well it would run but you could hold the trottle wide open and the motor will not rev out. it would idle and thats about it. he got tired of it and sold it to me for $200. the case was leaking badly tho so i split the case and silicone the case halfs together. however before i was going to assemble the jug back on i noticed the two port holes in the piston. which way do the port holes face????? towards the exhaust or to the intake?? my guess is that they would face towards the intake however im way to used to 4 strokes were there are no ports in the piston. could this be why it will only idle, and no power. the ports look just like the ports in the head so im guessing he installed the piston backwards. if you guys could help me out it would be greatly appreciated. thanks

 

Typically there is an arrow on the face of the piston. It should be aimed forward (in realationship to the engine/vehicle).

 

see thats what i thought and it got me wondering cause there is no arrow. just one side solid piston and one side with distinkt port holes in it???

 

ports go toward intake..

 

alright man thanks alot. ill swap it around and see what it does.