My son has an 03 Viper 90. I was wondering if there were any restictions besides the rev limiter on the machine? I've found a pipe & silencer that I'm planning on getting for it. Is there anything else I should be looking to REMOVE from it to give it more oomph? I've found many aftermarker performance mods for it, but I'm not really interested in spending the kind of $$$$.$$ to make it go 100 MPH, uphill in the sand, pulling a 20' loaded trailer, against a massive head wind. [img]i/expressions/face-icon-small-tongue.gif[/img] Know what I mean?

 

We have a very early 04 model,it actually says it was built in Jan 03 so its probably the same as an 03. The only restrictor on it was the green wire on the back of the CDI box.It should do around 30 mph (give or take a couple mph) with everything wide open.Surprisingly with me on it (200lbs) vs my son who is only 45 lbs the bike only slowed about 2 mph with the extra wieght.I think you could probably change the gearing a little bit and gain some more top end.We had the head milled and it boosted the bottom end grunt a little.

 

M Janzen,

Trust me on this one. Unless you are getting the pipe from WRH, then you are wasting time and money. The only other performacne pipe that fits it is the Tomco Ex-Pipe and it will not run with that pipe. A 50 will but a 90 won't.

If you are looking at the KPII pipe, it is the same as stock, don't waste teh money.

 

sometimes theres a restrictor in the head pipe , just unbolt it from the motor and look to see if theres a washer tacked in there. My sons 50 had one , popped it out with a screwdriver and what a difference. Its like a different quad.

 

order a pipe from www.hetrickracing.com. if you do you have to remove the battery and the oiler will give you a lot more top end. it is about 300 and it comes with a clutch kit. or just remove the oiler and premix at 36 to 1

 

As far as I know the rev limiter ( green wire) and the throttle limiter are the only things on the 02 and newer holding them back.

 

Yes, you should remove the stock head and replace it with a performance head, the same goes for the cylinder, reeds, and exhaust.