I'm in the process of putting an HPD PIPE, SILENCER, CLUTCH KIT, and K &N on my 2003 TB. What is the fastest quad I'll be able to drag? YFZ 450 ???

 

ahh i don't think that u will b able to take a yfz.......but what kind of clutch did u get and where please answer!!!

 

I got the HPD Aggressive clutch kit.

 

You can probably give a warrior and a 400ex a run. The pipe and clutch kit help alot, but it'll take some porting for the list of things you can outrun to really grow!

 

You will smoke the warrior and easily outrun the 400ex. A stock 400ex is just a little bit faster than a tb400. You should be able to play with stock Z400's. The pipe.clutch kit,air-filter add a lot of power to the tb400. Polarisfreak made a good suggestion about getting your cylinder ported to really kick some booty!

 

DITTTO on the porting but until you are ready get you a set of good reeds.

 

How many mods can you do before you should change the stock piston?

 

With what you have I wouldn't do much more. The stock cast pistons tend to break and can cause some major damage. Go with a Weisco piston. They are forged and lots stronger than stock.