my son has a ds 50 ever since it was new it wouldnt rev out .theres no change in seep or rpm after half throttle .ive checked air filter gas filter exhaust is clear .fuel flows is good carb is spotless .are these carbs over jetted from the factory too slow them down ?

 

Is the carb slide opening all the way. Theres a restricter from the factory that only lets it open 1/2 way. You might also check the pipe end cap/ spark arrestor screen and make sure it's not plugged with the wool crap the DS has in the pipe.

 

where is it restricted in the carb or throttle?the pipe is clear even unbolted it to test .thans for ur help

 

ok the exhaust is clear the throttle opens all the way .does these quads have a rev limiter in the cdi ? if so where can i get 1