Pull your plug & look at the color on the electrode. Dark brown, or black is running rich, light tan, grey or white is lean If lean you should hear the exhaust popping at wide open throttle. If lean clean the carb paying attention to the holes in the jets, & small holes in the emulsion tube of the pilot jet. Look for restrictions/small grains in the holes. This can be a result of ethanol gas. Try to use non-ethanol gas if possible. Check the float level also. If rich again clean the carb check float level & if hollow floats shake them to see if you can hear gas sloshing inside, if you can they have a leak. Replace the float Black sponge floats push your finger on it if you see a wet impression around you finger it's water/gas logged replace the float. Also test the choke/auto by-starter which would cause the bike to run rich if defective. Couple of other things the diaphragm on the top of the carb controls the opening of the slide. The 1st 1/4 throttle is the butterfly then vacumm on the diaphragm opens the slide as the engine needs. Check it for holes cracks or folded in. If this doesn't help could be in the variator or clutch bad rollers, look for flat spots. Or dirt try cleaning parts that move or slide. Hope this helps!
