i have a 2000 honda trx 400 ex and i was wonder which is the safest to go sense the bike is air coooled . i am planning to buy a big bore kit and dont know what size to buy dont want to put my bike in danger of blowing up. let me know your expierences with these big bore options on air cooled bikes. thanks
I can't help you but check out this site. You will probably find an answer there.
http://www.exriders.com/vbb/forumdisplay.php?s=&forumid=64
I would go 416 so you still had room for the 426 next time. You will notice the bump in comp. from the new piston more than the bigger cc's