gy6 150cc won't engage forward only reverse
 

:huh: my gy6 runs great however i cannot get it to engage into forward. reverse works just fine. its like it wants to engage into forward then pops out. engages, then disengages. when i got this gy6, it engaged fine, then slowly it started to pop like the chain was skippin a tooth or somethin and kept getting worse. now it wont stay engaged in forward. please somebody's gotta know whats causing this. i'm losing my mind trying to figure it out.:eek:

There are a couple of different forward/reverse gearboxes used on 150cc GY6 engines. These are add-on units (not really part of a GY6 engine) that mount on the output shaft that drives the wheel in a scooter (GY6's were built originally for scooters).

My 150cc GY6 quad F/R gearbox did something very similar to yours. The first symptom was occasional lurching going forward (I thought it was the CVT gearing down for some reason). Eventually it progressed til the gearbox would pop out of gear going up a hill.

You probably just need to adjust the linkage. It's touchy. You want to adjust it so that when you put it in forward gear the actuating arm at the gear box it is going a little bit further. It you adjust it too far the reverse gear will start lurching when backing up.

Mines doing the exact same only when keep it in reverse for a while it will get stuck I think it's my clutch but I'm not 100% sure... Any ideas before I get a new clutch?

It won't be the clutch. Jumping out of gear is either the linkage to it needing adjustment or worn gears/dogs in the gearbox. As Lyn Edwards wrote, either a gearbox is included in the case behind the rear CVT pulley or a separate box may be fitted to the rear axle. Sticking in gear is a bit more unusual, and more likely to be worn gears, but idle speed set too high can cause this problem.