I've always had this problem but ever since I changed from 21X7X10 shedders to 19X6X10 MX Holeshots it has gotten more pronounced.

Basically my 86 trx goes straight on the street but when riding off road, under aceleration at high speed the front end gets very squirly. His has gotten much worse since I've changed tires. I read the service manual and it calls for a +10mm difference between the center front of the tires and the center back of the tires so the tires are pointed inward slightly. I have it on the money and it still wanders or pulls to one side when going fast and acelerating. It doesn't pull to one particular side. If I'm coasting fast there is no trouble. I also have about a 1 or 2 degree negative camber, could this be the problem? I have stock arms with new bushings, i checked the steerer and tierods and they are all tight.

I expected the 19s to not be as good a top speed but this is down right dangerous.

 

The camber might be affecting it, but I doubt it would make that much of a difference. I have the camber on my Shee set to -2.5, and it tends to wander on the road, but not in the dirt. Have you checked to make sure your tie rods are perfectly straight? If they're off just a hair, they will make a world of difference, even if they are aligned correctly. Good luck finding it... Even though everything I said doesn't really help you out..

 

bump

 

Set both tires maybe 3/4 to 1 inch toe out this should stop them from wandering.

 

The more flat to the ground the tire is the more this will be noticed. When under acceleration depending on the terrain the tire may get more traction on one side more than the other causing this problem. The best way to fix this on any quad would be to buy a more rounded tire if it is really that big of deal. The lower the profile the worse it will get. Air pressure could be the blame if you noticed it always pulling one way more but generally the tire is the problem. With this the higher the air pressure will help to because the less the tire will flex when your weight is moving around. In my opinion you will never make it perfect with a lower profile tire but you can make it better.
Hope I could help.

 

i think it is because the motor is pulling hard and it is causing loss of traction

 

That is what I am thinking, I've noticed it ever since I installed the 38 Air Styker now that I come to think of it. I think I might need to gear up to soften the hit, currently running 14-38 and I still have to take off in 3rd gear when drag racing on dirt.

 

I've noticed that if I run low pressure in my tires it can get a little squirrely, and if your front brake pads are sticking slightly your front end might act in this way especially under acceleration on dirt because the tires aren't really touching the ground with much force. These are some variables anyway in case it isn't your alignment and/or camber.

 

front front tires are at 8 lbs. each and the brakes are fine. I think it is a combination of too much power and a slight too much toe in, I'll change to toe-in and will try it out tomorrow.