When rolling the quad in neutral there is a loud "click" and you can feel it wants to lock up the tires, this happens when rolled forward or reverse in neutral. I drained the oil and opened the case up but didn't see anything jumping out at me so I could use a little help as far as what to check. When the quad is elevated forward and reverse gears work but that click/skip will show up from time to time. Back story, this quad was bought brand new and is maybe a year old, the chain jumped off and bound up so bad it was a real bear to get out. Once I got it out the clicking started and it got parked for now. I'd prefer to trouble shoot a little before buying parts but I am not sure if this is a clutch issue or something else.

125CC Chinese Quad

Any help is greatly appreciated.

 

Could be a gear with a tooth broken off, but are you sure the chain is not catching on something, or a sprocket tooth bent?

 

It crossed my mind last night that the chain was loose so I checked today after reading your reply and the rear end is a bit loose and crooked. I will drop the chain tonight and see what that does then tighten it back up and roll it around. The drive sprocket and rear sprocket looked ok but I could see the chain popping in its current set up, there is some wiggle in the rear swing arm and chain, I guess I was more in panic mode and went right to the motor. Another question, right foot casing is cracked inside, need to replace, is this a common problem for others?

 

Well its not the chain, tight or loose it still clicks and grabs something that wants to stop the wheels, but it does grab harder in one direction vs another which may be a clue for someone with real knowledge. Next question, to tear into this further, will I need to order special tools for the fly wheel or clutch? I'm having a hard time finding anything on you tube about this issue so I am basically ripping into this engine and looking for something broken, but I have no idea what I am looking for. Any ideas are welcome...

 

If the engine is the normal 125cc Honda Cub clone, strip down and rebuild instructions are out there for them, though transmissions vary depending on if they are rev and go, four speed or have a reverse. The ones with gears are very much like Hondas so look for Honda 90/110 workshop manuals. If however the engine is a GY6 belt drive, the gearbox is separate to the engine and a fairly simple thing to strip.

 

Thanks for the heads up Merryman. As far as this quad goes, just F-N-R for gearing, no belt drive. I rebuilt the top end of my other sons quad a couple months ago so I can tear into the engine pretty confidently I just don't know exactly what I am looking for in this case. More YouTube time is in my future I believe...

 

Well I finally got into this. Removed the top end, clutch and shifter, got the inner case open and found a busted off tooth and a flat spot on the other gear. I have no idea what any of this stuff is really called but I have new parts on order from VMC. Does anyone know how to remove the entire gearing assembly? There are 2 shafts and one thing that looks like it engages forward or reverse. I can pull out the shaft with the flat gear but the other seems locked in along with whatever that engaging part is called. It looks like I can pop off the snap ring and replace that one gear but the part I bought is a whole spline/gear set up. I would prefer to swap out the whole assembly if possible, and it seems like it moves up and down, but I just cant get it to pull all the way out. Anyone have any ideas???

For anyone that is wondering, the missing tooth gave the shafts enough slop to pitch the gears tooth tip to tooth tip which locked up the wheels. Once enough pressure was put on the tires it would power over that bad engagement but eventually I can see this ruining god only knows what. Why it happened? I believe I let someone that was unfamiliar with the quad ride it, they revved hard to peel out, wasn't in gear, slammed it in gear, bam... I have had many other atvs and have never encountered this issue before. As far as the chain getting locked up, that was likely not the issue I feel, I only noticed it after that so who knows how long it was doing that when the rider was on it as they were a novice and I was on my own machine not paying attention to what they were doing.

DRN

 

Well I got it back together, new gaskets and oil and all is well. Carb is now popping so I have a new carb on order. The factory ones on a lot of these are not adjustable and new ones are $16 so I will now have these on all three of the kids quads. Picked up some cheap air shocks as well, night and day difference in suspension. Going to run them for a few weeks and if decent enough, get some more for the others. Looking into a rear shock as well...

Well, problem solved, take care out there...

DRN