What to do next

I have a 2002 400ex with a full exhaust and k&N and jets. I'm looking to do an upgrade that is inexpensive but will give more speed. Anyone know what I could do?

[trx400ex]

buy a 416 kit....150$....xr cam...100$ and a bigger front sprocket...20$====270$ or less, also a wb rev boxis only 100$ and will supposedly make it 8 mph faster

[wheeltrax]

If you want more speed for less that $50 you can step down the size of your rear sprocket. Doing this of course will take some of your acceleration away. :(

Where can I find a 416 kit and can I do the work myself?

At the top of the page there's a link to marcums atv,,,,,he'll have everything you need for the 416 kit,,,I know cuz that's were I got mine and he'll have the best price of anybody in the world,,,and yes you can do the work if you know what your doin..:D

[knighttime]

On the 416 kit, do u have to get the cylinder bored?

That would be a big-O,,,,,,YUUUUUP!!!! .080 over which actually takes it from 85mm bore to 87mm boreI do beleive...

[knighttime]

When you get your engine bored, does it have to be removed from the frame?

[barbwire44]

knighttime, you can leave the motor on the frame and disassemble there, but it is ten times easier to remove the motor from the frame and alot cleaner. I put a 440 kit together for a friend it took 15 minutes to remove the engine from the frame it's really easy the hardest part is removing the swingarm bolt if it has rusted up. So i would definately pull the motor out, and send the jug out to be bored.;)

What will an XR cam do for performance?