Won't rev with rear wheels on the ground,lift it up and it revs up fine. Just did a lot of work to it,last owner neglected everything. He did a lot of water and mud hole splashing thru riding. Replaced air filter and repaired box,it wasn't even holding the filter in place or sealing.

 

Would help to know what all you've done,but one thing I'd do is replace the air box to make sure it's sealing good rather than repair one. They're cheap ($18.50) and include a new filter.https://www.ebay.com/itm/NEW-Air-Fil...5WmArN&vxp=mtr

 

I replaced rear end bearings,drive shaft bearings and seals,all brakes and tiered ends. I just installed screws that hold the filter housing together,it only had 1 in it and wasn't sealing at all. The housing and elbow goin to carb were caked with dirt , even in the clean side. It ran ok before . Is there only 2 adj screws on carb,idle and the 1 that is at an angle?

 

The screw in the middle is the idle adjuster.The one at an angle is the air screw. Make sure the carb is clean,jets clear and open. Also make sure the small hole in the bottom of the carb bowl is open. Spray carb cleaner and air through it. It should spray out the opening close to the top of the bowl. Seems some people forget about that one. You can do as the manual states and go from there:
AIR SCREW ADJUSTMENT
1. Turn carburetor air screw in (clockwise) until lightly
seated. Back screw out the specified number of turns.
Air Screw Adjustment
1.5 turns out
Warm up the engine to operating temperature (about
10 minutes).
3. Set idle speed to 600 RPM.
NOTE: Adjusting the air screw may affect idle speed.
Always check throttle cable freeplay after adjusting idle
speed and adjust if necessary.
4. Turn the screw in (to richen) or out (to lean) the
mixture. Adjust air screw for best throttle response
and smooth idle.
5. Re-adjust idle speed if necessary.
Wouldn't hurt to make sure compression is at least 115 psi also. Plus there are a few videos you can check out on youtube.

 

Thank you. I goofed when I asked ? in 2 places. I don't have the process of posting and replying down yet. I'm pretty green to website stuff.

 

If it had gears,it acts like it has a hi gear only,roll it down the driveway a bit and it goes fast and revs hi until u start to climb up grade

 

Sounds like you need to check into the belt and clutches. Could be as simple as a worn/stretched belt or clutch parts need replacing.

 

the belt and pulleys needed cleaned a lot more,it was a greasy mess in that whole housing when I started. It goes fine now. These things are peppy. It would whip our trx 90, and it has a pipe and good air cleaner

 

Yes when you get them running right these little 2 strokes will out run a lot of the smaller 4 strokes.