Yamaha Rhino 660 Clutch Sheave Installation

| November 18, 2009 | 2 Comments

By Steve Dex Charon, UTVCrap.com

The job of the transmission is to change the speed ratio between the engine and the wheels. The transmission uses a range of gears — from low to high — to make more effective use of the engine’s torque as driving conditions change. The gears can be engaged manually or automatically. Today’s side x side vehicles all use a type of automatic transmission called a continuously variable transmission or CVT.

Unlike traditional automatic transmissions used in cars that are much too heavy for a side x side vehicle, CVTs don’t have any sort of gears. The CVT operates on a pulley system that allows an infinite variability between highest and lowest gears with no discrete steps or shifts.

CVTs used in Yamaha Rhinos, Polaris RZRs, Kawasaki Teryx, Polaris Rangers and Arctic Cat Prowlers have three basic components:

  • A rubber belt
  • A variable-input “driving” pulley
  • An output “driven” pulley

The variable-diameter pulleys are the key to a CVT. Each pulley is made of two cones facing each other. A belt rides in the groove between the two cones. When the two cones of the pulley are far apart, the belt rides lower in the groove, and the radius of the belt loop going around the pulley gets smaller. When the cones are close together, the belt rides higher in the groove, and the radius of the belt loop going around the pulley gets larger.

One of the two pulleys is connected to the crankshaft of the engine. This pulley is typically called the drive pulley. The second pulley is called the driven or output pulley because the first pulley is turning it. The driven pulley transfers energy to the transfer case and onto the differentials, through the axles and out to the wheels.

On a Yamaha Rhino, the clutch sheave is part of the drive pulley. When clutch sheaves are machined, it allows the cones on the drive pulley to collapse even further which forces the belt even higher between the cones. This translates to a higher gear.

When one pulley increases its radius, the other decreases its radius to keep the belt tight. As the two pulleys change relative to one another, they create an infinite number of gear ratios.

Yamaha Rhino 660 CVT Cover

Yamaha Rhino 660 CVT Cover

The sheave is the engine driven pulley of the belt drive. The sheave is located under the black plastic cover under the drivers side seat. It consists of 2 sides, the inner side (called the fixed half by Yamaha) and the sliding side. It is the sliding side that is modified to add additional speed to a Yamaha Rhino.

Yamaha Rhino CVT

Yamaha Rhino CVT

If you look at the picture below, you will see the wear marks where the belt stopped short of using the entire pulley face.

Yamaha Rhino 660 Clutch Sheave

Yamaha Rhino 660 Clutch Sheave

Inside the sheave are rollerways. It is centrifugal force that forces the rollers to push outward on the ramps in the rollerways, that in turn forces the sliding half of the sheave towards the inner fixed half. That in effect closes the gap in between the two pulleys forcing the belt to ride higher. By the belt riding higher in the pulley the ratio of the belt drive system- That’s why it’s really a continuously variable transmission (CVT) and not a ”clutch” at all. The term clutch kit is just a generic term used by everyone in the aftermarket industry.

In this picture you can see the inside of the sheave and the roller ways.

Inside of Yamaha Rhino Clutch Sheave

Inside of Yamaha Rhino Clutch Sheave

There are 8 rollers in a Rhino’s sheave. Depending on the machine the roller will vary in weight to change how fast the sheave will move or ”shift”.

Here they are with the outer cover and cam plate removed. That is where the rollers will rest at idle and when the sheave is fully open.

Yamaha Rhino 660 Sheave with Rollers

Yamaha Rhino 660 Sheave with Rollers

The rollers used in the 450 and 660 Rhino have removable covers. The factory roller on a 700 Rhino is one piece, our rollers for the 700 are 2 piece.

If you are simply replacing the outer sheave half to gain more mph than you do not need to separate the roller weights. If you are adding a duner/sport or big tire kit where you are changing the gram weight of the rollers you will need to separate them from the covers.

Yamaha Rhino Roller Weights

Yamaha Rhino Sheave Roller Weights

The easiest way to do that is to use a socket that just fits inside the roller cover to push the roller out.

Yamaha Rhino 660 - CVT Roller

Yamaha Rhino 660 - CVT Roller

You do need to pay attention to which way the roller comes out of the cover. There is a lip on just one side of the cover that, the roller only comes out and goes in one way.

The lipped side of the roller

The lipped side of the roller

When you are reassembling the sheave you will need to apply grease to the rollers. About a teaspoon for each roller will be enough. Applying a little to the four walls that the slider rides on will not hurt either but after the first time the sheave spins the grease will end up on the walls anyway.

Clutch sheave with grease applied

Clutch sheave with grease applied

The cam plate is what holds the sheave on the engines output shaft. On the 450 and 660 Rhino the cam plate buttons are each two pieces, a metal insert with a plastic outer.

Cam Plate

Cam Plate

The Rhino 700 model has buttons that are only plastic/nylon. These have been shown to wear out prematurely and can be replaced with the older equivalent. cam plate will look like this when the buttons are installed.

Rhino Cam Plate with buttons installed

Rhino Cam Plate with buttons installed

On the 450 and 660 machine the metal insert should fit like this if you put it on without the plastic housing. If it does not the cam plate is worn beyond use and needs replacement.

Cam Plate

Cam Plate

Using a worn cam plate can result in broken rollerway walls as the rollers will be forced to cock to the side.

This is the cam plate installed (less grease).

Yamaha Rhino 660 Sheave with Cam Plate Installed

Yamaha Rhino 660 Sheave with Cam Plate Installed

All Rhino sheaves will have an o-ring under the sheet metal cover. You need to leave the o-ring in place as it keeps the grease from leaving the inside of the sheave. If you damage yours while disassembling the sheave it will need to be replaced. It will go in the groove around the outside of the sheave.

Clutch Sheave with o-ring

Clutch Sheave with o-ring

The outer cover will be a tight fit over the o-ring. When the sheave is properly assembled it will look like this.

Assembled Clutch Sheave

Assembled Clutch Sheave

Do NOT apply grease to the shaft the sheave rides on, it will end up on the belt.

When installing the sheave it is important to hold the cam plate tightly against the sheaves hub. Otherwise one or more of the rollers may fall out of it’s pathway and the sheave will not function correctly.

Installing the Clutch Sheave

Installing the Clutch Sheave

UTV Crap Yamaha Rhino 660 Clutch Sheave and Clutch Kit Installation

UTV Crap sells machined Rhino clutch sheaves, clutch kits, clutch spring compressors and just about everything else for your Yamaha Rhino. Check out their Yamaha Rhino Clutch page at: http://www.utvcrap.com/index.php?cPath=26_132

About UTV Crap:
UTV Crap designs, manufactures, fabricates, packages, markets, and sells parts & products for the UTV industry for all major manufactures of UTV’s and side by sides. UTV Crap is located in Phoenix, AZ at 4244 W Dunlap Ave. UTV Crap can be reached either by visiting the website 24/7 at www.UTVCrap.com or calling the retail location at 623-934-3070, Monday-Saturday 9am – 6pm.


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Category: How Tos, Tech, Yamaha

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  • shane patterson

    my 2007 rhino 660 is making a grinding noise when i go down a hill or hit the brakes. I just got it back from the shop having the brake pads replaced thinking it might would have been the rear brake that was making the noise. well i got it back from the shop and still the grinding noise and now it makes it when i turn off my rhino. Do you have any answers or suggestions on what could be causing the grinding noise???? I have searched all over the internet and all i find are people with the same problem and no answers.

  • jo

    check your rear diff,where it mounts to frame ,they sometimes crack here,front and back and cause grinding noises,especially when applying brakes ,because rear diff twists,bolts break or ware,but most times frame cracks.