How long have you've been runing this motor and what is the regular maintance that you do? besides the standard stuff like oil changes.

 

I looked into getting a 440 Kit on my 400. In the end it was going to cost over $2,000 for all of the correct parts and machine work. If you ask some engine builders the 440 kits with the higher compression ratio can crack the case. I talked to Sparks Racing and this was confirmed. Another $1,200 for shock (Elkas). I finally went and bought a Cannondale Speed.

It is designed to be a 440, water cooled, fuel injection, better shocks, if you start to add it up it came up less for a new bike than rebuilt the 400.

Just my thoughts

Smitty