big bore battle

[yami]

i own a 99 yz 400, im looking for a big bore kit and my local dealer told me that they only carry wiseco and they dont list one for my bike

anyone have any reccomendations to whom may solve my power fettish

[Derekj426]

ThumperRacing

Give that a shot

[Rich_Rohrich]

i own a 99 yz 400, im looking for a big bore kit and my local dealer told me that they only carry wiseco and they dont list one for my bike

anyone have any reccomendations to whom may solve my power fettish

Wiseco had a 2mm overbore (94mm = 417cc) kit available for the early 400s for a long time. The problem with it was the piston was about 40 grams heavier than the OEM piston. When guys used that piston with the early rods that had a lot of hours on them there were some rod failures. You can fit the 426 rod to your crank and use the stock 426 (95mm) piston along with the stock 426 barrel and have a really fun rideable engine for a minimal cash outlay, plus by using the stronger 426 rod it puts you in the position to go to 97mm/444cc if you want.