I haven't had any experience with them because I don't own a 400EX, but I have also heard from a lot of people, that the 426 is more dependable.
Sounds like good advice to me.I would go with the 426 if you are a pitt rider. You know, haul it in and stay in the same area. If you are a trail rider trying to cover 50 plus miles in a day, I would keep it stock. Nice and reliable.
426 cc 11:1 Big Bore Kit Honda TRX 400EX TRX400EX XR400: eBay Motors (item 270294486190 end time Jun-20-10 17:09:55 PDT)yea man thanks, any one know where i can find the kits?