[Muzzymoto86]

Im trying obtain information on the subject of stroking not boring. I dont want to change the top end bore but would like to do head and valve work along with stroking the bottom end to get more horseys. From what ive seen a honda 450 carb will work as well as a cam from an XR400 to get more power. changing the top end seems pointless or rather not worthy with the 400ex's. can i get away with just stroking it out? any suggestions and or opinions apreciated. thanks

 

[TRX2fiveO]

I'm sure you can but I've seen a 400ex with the 440 big bore kit and it was extremely quick. if you rework the head along with the kit you will see a very noticable difference. Port polish the intake and exhaust ports also port match will help along with an angle valve grind, stage 3 cam ect. you could easily see 90 mph or better.

 

[Saber6]

Agree^^^^^^^^^^^^