yam wr cylinder swap

hi there,

i'm about to start what i think will be a serious project, but i'm a little stuck on the dimentional side of things.

i'm trying to build a 450 motor using a 400 short stroke bottom end and 450 head and cylinder.

i'm not sure if you van fit the wr/yzf 450 cylinder onto the 400/426 crank case, or failingtht can the 426 cylinder be bored out to 98mm from the 95mm STD.

i will be posting pics of the project as i go on the yamaha wr section if anyone is interested in watching the progress.

thanks for any help in advance.

Given the fact that the largest kits that were ever offered for the 426 were 444cc kits, (97mm bore) I would doubt that it's safe to run the 426 cylinder out to 98. A 450 can be bored to 98, however. IF you can stand a 450 cylinder on the 400 crankcase (I have heard you can, but the source is unreliable), and you were to do that, you'd end up with 452cc. IMO, it's a long way to go for 8cc more than you'd get with a 444 kit.

I have a 400 bored out to the 444 and I love it. The next step that I am aware of, is you can get the crank stroked a additional 2mm which I think brings you to around 468 cc. The place I saw the does the stroking of the crank is http://www.powroll.com/P_YAMAHA_YZFWR426F.htm

I haven't worked with them or heard any feedback on them, so you may want to research them a little or give them a call.

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