I just picked this atv up for $200 bucks, cleaned the carb and drained the tank, runs great...however when I shift from neutral to forward or reverse the gears grind, now following the rear brake cable looks like it somehow maybe doubles as a clutch? When I squeeze the brake cable it idles the engine down so low that it stalls....WTF? It has a little button also on the handlebar, the reverse limiter maybe? This is just a beater quad but I'd like to be able to shift without grinding the gears, thanks for any help!

 

sounds like the clutch is engaging the belt. Pull the clutch cover and inspect your primary.

 

you might have it idled up too high as well. as far as the break making it stall something isnt righjt for sure.