I bought a 2002 xr50 a few months ago. Cleaned it up, painted the frame, got new plastics and put it back together. I cleaned the carb, drained the gas, put fresh gas in, new sparkplug, and put in a new air filter. The bike fires right up and idles, but it sounds a little high. There is almost no throttle response when i twist the throttle though, and no power. No carb adjustments seem to make any difference. I've pulled the carb a couple of times now and cleaned for good measure, but no change. I'm stuck on what to try next.