I finally got this thing started after sitting for 2 years busted in some guys backyard. I cleaned and rebuilt the carb using a Shindy kit from ebay. It's starts and idles ok, but if I accelerate at all it seems to run really bad. Pops and stumbles and just sounds terrible. Unless I hold the yellow reverse override button then after a few seconds it does seem to clear up some and runs much better. It's Still kinda rough though but noticeably different and better. If I ride it around at 1/4-1/2 throttle pushing this yellow button and then let off it will die or come close to it. The override is doing something in forward. I am at a loss.

Its a new ATV to me, Here is what I have done.

New Plug, New factory air cleaner, Stock pipe, #40 Jet, 2 turns out on mixture screws (1100 Ft elv) 90PSI compression at Wide open throttle, New Pull Start kit, Fuel Pump, Fuel Shutoff Valve, Fuel Filter, Fuel Lines & Full fluid change of every fluid,

Also it smokes really bad, my guess is stuck oil ring, I did soak the cylinder in Marvel Mystery oil when I first got it because the previous owner did say it smoked a little. It's not a little it could be a good mosquito fogger.

When I push that button though it does have really good power but I shouldn't have to do that.

Any thoughts.

 

Later models had the limiter going though the speedo,but you can bypass having to push the over ride and see if this solves the problem.
"Pre 2003 and almost all models that do NOT have the combined override/Speedo function button.

Trace wires from the override button (gray/white & gray/orange) Cut the gray/orange and tape up both ends. Cut the gray/white and tape up the end which goes to the override button. Connect the other end of the gray/white to the red/white (ignition supplied 12v)" Plus not a bad idea to check the valve clearance and also the exhaust cam lobe as this model falls in the year range that soft cams were a problem on wearing down. .006 intake and exhaust.