I have a 08 trx450er and i know the motors are really close. I'm not sure which one fits the 2-wheeler but if you want a lot more power and don't want t gut the head, this is a good one. Go to www.ctracing.com - honda - trx450 and look. You don't lose anything and at 3/4 with the wire cut on the cdi, it comes unglued. You'll notice it building more at 1/3 throttle. Then twist it back and hang on.