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Hello! My sheave got fixed! I put the quad in reverse....reverse light came on....and the quad backed up. I went forward, and everything was great. Then I tried reverse again, and the light would come on, but the engine would only rev up, it would not move. This has lasted for a couple weeks, then yesterday, when I started it - I tried reverse....and it moved, I moved it forward to try again, and then it refused to move again. I don't know much about these machines (Yamaha) but it seems like even though the reverse light comes on, something isn't telling the bike it's in gear....where should I start with this problem?
 

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Welcome from Colorado.
You can tell use more about your ride so we know for sure which engine and drive system you have. It sounds like a primary pulley problem, like the nut came loose, or was not tightened correctly when the sheave was installed. This will cause the fixed sheave to be loose, or the cam plate to be disengaged from the splines.
 

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Welcome from Colorado.
You can tell use more about your ride so we know for sure which engine and drive system you have. It sounds like a primary pulley problem, like the nut came loose, or was not tightened correctly when the sheave was installed. This will cause the fixed sheave to be loose, or the cam plate to be disengaged from the splines.
This is a 2005 Bruin 350 4x4. I am unsure as to what you mean by the pulley though. I tightened down the sheaves to the correct torque - and H works fine...but I don't know much about the mechanics either!
 

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This is a 2005 Bruin 350 4x4. I am unsure as to what you mean by the pulley though. I tightened down the sheaves to the correct torque - and H works fine...but I don't know much about the mechanics either!
OK....
You can add a signature to your account and list your bike and all mods as added. The signature appears with ever post you make so we can keep straight on your ride. We have 10's of thousands of members and don't want to make mistakes here.
You can get the proper torque value on the wrench, but if the belt is pinched in between the sheaves when applying torque, part of the torque pressure can be absorbed by the belt so the cam plate is not tight. Then when you hit the gas and cycle the primary the first time, the belt moves and the sheaves wobble and the nut can come off the shaft threads.
The transmission can be in the right gear and not get power through a slipping belt.
I suggest not starting the engine until you take look under the cover. Others have pinched the belt, and if you did, hope the sheave splines are not stripped.
 

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Discussion Starter #5
OK....
You can add a signature to your account and list your bike and all mods as added. The signature appears with ever post you make so we can keep straight on your ride. We have 10's of thousands of members and don't want to make mistakes here.
You can get the proper torque value on the wrench, but if the belt is pinched in between the sheaves when applying torque, part of the torque pressure can be absorbed by the belt so the cam plate is not tight. Then when you hit the gas and cycle the primary the first time, the belt moves and the sheaves wobble and the nut can come off the shaft threads.
The transmission can be in the right gear and not get power through a slipping belt.
I suggest not starting the engine until you take look under the cover. Other have pinched the belt,and if you did hope the sheave splines are not stripped.
I guess I am confused - wouldn't Forward not work if what you're saying is true?
 

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Each pulley has two halves, each called a sheave. If these are loose there might not be belt pressure. If there is nothing wrong with the c.v.t. drive, you probably have bigger problems.
As you just reported working on the sheave I am betting the problem is in the c.v.t. cover, not the transmission. Just an educated guess through the computer screen.
As for which direction the bike might move, or might not, every time you let the wet clutch disengage everything can relax for a different result when you hit the gas.
 

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Discussion Starter #7
Just wanted to provide a small update here. I opened the CVT cover and checked the sheave. Everything was fine and I confirmed it was torqued properly. The ATV will sometimes go in reverse. If you put it in reverse and rock it - sometimes, if you get lucky, reverse will engage. I can't figure out what its deal is - but it would seem like a connection or something. The search continues!
 

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It may help if you post a video of the cvt with the cover off so we can see what happening when you put it in reverse. Put the Bruin on jack stands and video it in forward and reverse.
 
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