piston on stock motor!

[EXDUNER127]

My buddy has a 440ex with a 13:1 je piston and the works, and now he is going bigger. He gave is piston because it was still in good condition, (wasnt used much) what will happen if i put this in my motor with say a stg2 cam, is this too big with out the porting and oversized valves. will i get anything out of it, or should i just leave it out?

[400exdad]

I think you'll see some gains with it (and like it), but if you really want it to work good, you'll need to do the headwork. A big question that I think is important is: Are you prepared to run race gas?

[EXDUNER127]

do you run full race gas or half and half? so i will get some nice gains but more if i do the the headwork right. is there anything else i need to get right away or will the piston and cam be good for a while?

[cals400ex]

you will need to run straight. i have a feeling you will need 110. that compression is really high. i would have new heavy duty head studs put in while your at it too. a port job would only help the bike out. you wouldn't need it right away though. i would definately add a cam when you do this though.

[honduh440]

if thats a 89mm piston "440" and ur engine is stock you will need to bore the cylinder on your bike as well. full race gas is a must if you run half and half or just pump you will blow head gaskets. but power wise by adding this mod and cam will be awsome