Hi guys,

I bought a TaoTao 125cc ATV with RN123 gears back in 2012. After putting about 2hrs on it every time I would go to switch into 3rd the engine would start jerking the ATV around so I would only use 2nd and ride slower. After about 10hrs I tried switching to 2nd and it started doing the same thing accept it was making a loud clanking sounds and wouldn't even move, it would just act like neutral. So now all that works is 1st. I know I will probably have to tear the engine apart but I would just like to know what's causing this problem.
Thanks.