9R piston swap into 12R parts thread

[newyorkbuell]

Hey guys, i have been around here and badweb lurking and seeing how people have been doing the 9 pistons in the 12's. Well i have been thinking about going ahead and doing this in the winter and i wanted to get a feel for where people that have done this swap buy there pistons, gaskets, and other random parts needed to do the work. And even how the tuning changed and dyno charts and or butt dyno talk. Lets get talking.[cool]

 

[Sirius815]

From what I can remember, it's a straight swap (with the exception of the tuning of course). I know cometic has the gaskets in various thicknesses so that you may lower compression back down just a hair if you can't always get 93 octane to prevent pre-ignition.

I think I've only ever seen one dyno in a mag. I'd have to try and find my write up on the matter.

EDIT: Here you go -> http://www.buellmods.com/index.php/engine/xb12-motor-with-xb9-piston-fyi-v15-61

 

[buellxb9rs]

XB 9 piston w/rings : 22707-02 $101.60 ea plus shipping here:
Link

Gasket kit $82+ shipping: Link

 

[GOduc]

There are other things to consider:

Do cylinders need to be replaced?

Have cylinders been checked for out of round?

Have 9 pistons been adequatly balanced?

Consider having a set of lighter, stronger forged pistons cut?

 

[wolfo68]

xb9rs, don't use the stock gaskets. trust me

 

[buellxb9rs]

Those are not stock, stock gap yes but they are the cosmetic brand. Besides that, if the bike is running without problems I don't see why there is a need to check the cylinders.

 

[newyorkbuell]

Good call goduc I forgot that in the first post, I will deff go with cometic gaskets, and also I was thinking depending on how the cylinders look if I have to go with a over bore or not. I would like to go with a aftermarket coated piston, I always used weisco for the motocross bike but I don't know how the prices are for the xb12.

 

[Sirius815]

Best would be to call them. I doubt they are too much more than brand new pistons from HD.

 

[wolfo68]

last time I looked they were quite a bit more than the stockers

 

[Sirius815]

Ugh - that sucks. At least it's a better engineered one (well - if you believe the marketing).