I picked up a used 2004 2 stroke DVX90, I believe that the quad is totally stock and was able to get it up to 21.8mph with my 220lb but on it, I was just wondering if thats about right for a stock machine. Also I would like to change the rea gear and get a little more low end power, who makes aftermarket gears for the AC. Thanks any help or info.

 

Most of the two stroke 90s will do close to 30mph with all of the restrictors removed..I think the cats had something that kept the clutches from shifting out fully that limited top speed...Some of them also had huge rear sprockets for the same effect..

 

1st check that the throttle slide is opening all the way in the carb, there was a spacer that came on top to limit travel. Second is a spacer that could be in the center of the front variator clutch to prevent it from closing up all the way, hence preventing full shift ratio and speed.
The stock rear sprocket was way too big (40 something), we converted to a smaller 36 tooth from a Polaris 90. Most of these asian 90's are either 3 bolt or 4 bolt rear sprockets... common.
We have ours geared down with 20" Holeshot rear tires on it at 10K RPM it gets to about 35MPH but we weren't after top speed (fast enough for trail) but we were after throttle response and hill climbing ability.

 

Thanks, I am going to do a piston and rings as it smokes a little. Will a gear from a polaris bolt right up or does it need to be moded? I am basically looking for some more low end power.

 

I'd do a compression test before you put a new piston in.
They are 2 strokes and supposed to smoke a lil.

 

Right on, 2-strokes smoke in relation to the amount of oil being injected or mixed with the gas. Not like a 4-stroke that has oil in the crankcase that will leak past the rings if worn...
Try adjusting the oil injector lever and cable for less...