99 WR400... going BIG with the bore!


3 replies to this topic
  • redswr

Posted November 08, 2007 - 12:38 AM

#1

hey guys the top end on my 99 is about to let loose and i was wondering what the biggest bore most radical way i can set it up without dropping a whole new motor in it... i'm planning on it being a duner only.

  • Birdy426

Posted November 08, 2007 - 07:13 AM

#2

I know you can go 444 if you use a 426 connecting rod (the small end is bigger than the 400's), but you may be able to get more with a stroker...never looked into it. you won't be disappointed with the 444 set up. A set of Hot Cams and a good exhaust will REALLY wake that sucker up. Luke's Racing is the best price around for Big Bore kits and they usually have bored and plated barrels in stock that they will swap out rather than waiting for yours to get done. Eric Gorr is a close second on price, and does excellent work.

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  • 2grimjim

Posted November 08, 2007 - 07:45 AM

#3

hey guys the top end on my 99 is about to let loose and i was wondering what the biggest bore most radical way i can set it up without dropping a whole new motor in it... i'm planning on it being a duner only.


How much money do you want to spend on it?

http://www.powroll.c...A_YZFWR426F.htm

  • SXP

Posted November 08, 2007 - 12:48 PM

#4

hey guys the top end on my 99 is about to let loose and i was wondering what the biggest bore most radical way i can set it up without dropping a whole new motor in it... i'm planning on it being a duner only.


With the stock connecting rod, I believe you can go up to 420 cc. With the 426 rod you can go up to 444 cc. And then there's the stroker option as mentioned above. Whatever you do, rebuild the lower con-rod bearing at the same time.




 
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