[Lt250]

Hey guys i have a 2004 trx 400ex runs alsome. I want to give it more power and torch and top end. What can i do to make this happen. I love this quad but want more. I put a big gun es exhault on it. What else can i do

 

[Robsessed88]

440 kit has always been a good kit for them. Comparable power to a 450.

 

[mudliker]

Cam, port and polish better drive train can surely improve the performance.

 

[Cycletech]

A mild port Job along with a cam, header, carb mod and big bore kit will be good. You must be careful with the RFVC Motors because they like to hold a lot of heat in the heads and can cook the valve train. Run a good Petroleum/Synthetic blend oil and a large oil cooler if you can and change your oil more often then normal. Did you re-jet the carb after installing the exhaust??

 

[mudliker]

Or do a engine swap or better yet sell your current toy and buy a bigger and better atv.