Hey, I have a 2003 400I auto, LOVE IT, have about 330 miles on it, just looking to start upgrading it, any sugestions?? any good sites to look at?? what is a good power upgrade? don't really care about the cost, just let me know. Any tips or mods are welcome, mainly I need some good sites that sell aftermarket stuff for my ride.

 

Cat usually ships their quads with the Carb running a little rich. You can check this by running your finger up in the tail pipe, if it comes out jet black then it's a little rich, if it comes out browninsh then you're probably jetted ok for your altitiude. The first mod I'd do is go to dynotjet.com and get their jet kit cause you're gonna need it. Then get a high flow air filter and a pipe. You'll probably need to rejet your carb after each change you make. You'll should be into a little less than 500 dollars on the stuff above. I replaced the stock tires on my 02 AC 375 with 27" GBC Dirt Devils. I went with the 10" width all the way around as the 12 inchers were a little too big and I didn't want the tires to rob me of power too much. I must say, after throwing the Dirt Devils on, the quad rode like a different bike. With the wider tires up front and the stiffer side walls it was MUCH more stable off-camber. It was even, get this, easier to steer!

Theres a few wthings to get you going...


Good luck!