Has any one done this and how do they like it. Is the EX reliable punched out to 500cc.

 

I know quite a few with 440 kits and they seem to run fine. You might run a little hotter in the cylender area because it will become quite thin. I would imagine that it would be a exacutioner to all quads on a xc track and damn fast on a mx track. It might be a wheelie machine too. The kit looks top notch and Sparks is not known for cheep garbage and slow motors. All the sparks bikes ive seen are eyelid ripping fast, both 2 and 4 strokes