just bought an older motobecane v50 and cant seem to keep it running. the carb is clean. and is getting plenty of fuel. i adjusted screw all the way up to no avail. i still have to turn the throttle (which is very sticky) to keep the damn thing running. as far as i can tell everything is in working order, i have checked the points, the plug, the carb, the exhaust, the air filter, and nothing seems to be out of place. any advice? man i wish i could have found another honda express.