Clutch Maintenance

[Panterawill]

I dont see anything in the owners manual about clutch maintenance. Besides blowing out the dust and cleaning the sheaves, what else should I be doing?

 

[grader]

yamaha clutches are very durable and last many miles with only cleaning as you said. with many miles things do wear, eg. the bushing in the moveable sheave, the bushings in the weights and rollers, and the spacers. i have changed the sheave bushing on a clutch with apprx 15000 miles on it. i have yet to change out the others, as different weights have been in and out over the years. i also run a 911 cover with a larger bushing that is oillite brass instead of fiber like the stock cover. the slider pucks can also wear in the spider. if you change out any of these parts, use only genuine yamaha parts, as the aftermarket parts will not last and wear quickly. this also applys to the bushing and slider buttons in the secondary.

 

[Panterawill]

Where can I find info for adjusting clutch for new belt? I checked FAQ but found nothing.
Thanks

 

[THKSNOW]

Where can I find info for adjusting clutch for new belt? I checked FAQ but found nothing.
Thanks

There are none, just put the belt on.

 

[Blue Dave]

Where can I find info for adjusting clutch for new belt? I checked FAQ but found nothing.
Thanks

There are none, just put the belt on.

The secondary clutch can be adjusted for the width difference between a new belt and a worn belt by simply adding or removing shim washers on the three bolts that act to set the sheave separation.

 

[Panterawill]

What is the proper height in relation to the sheave?

 

[THKSNOW]

Where can I find info for adjusting clutch for new belt? I checked FAQ but found nothing.
Thanks

There are none, just put the belt on.

The secondary clutch can be adjusted for the width difference between a new belt and a worn belt by simply adding or removing shim washers on the three bolts that act to set the sheave separation.

Sure, that's true but... if you start with a new belt that's now worn and you've never messed with the secondary prior to this, I say just throw the new belt on and ride. If you're racing sleds it might be different but the average trail rider won't see any difference making the adjustments you described IMHO.

 

[Irv]

What is the proper height in relation to the sheave?

Blue Dave wrote.
"The secondary clutch can be adjusted for the width difference between a new belt and a worn belt by simply adding or removing shim washers on the three bolts that act to set the sheave separation."


I am also curious on this as I just purchased a new belt, and going by my current one, it sits too low in the secondary.
Just thinking here, but if mine currently sits low, then I will have to remove washers?
I did get 3 when I purchased the sled and they are on the small side, but I assume those are them?
Should the belt not sit slightly above the sheaves on the secondary?

Thanks in advance

 

[MT.man]

The adjustment on the secondary clutch is also to take into consideration a manufacturing variance of a new belt +/- 3/16" if your clutch is set up for a belt on the short side and you replace it with a belt on the long side,( or visa versa) that what you need that adjustment for. If you could buy belts that were a constant size you would be able to set it and forget it but the price of such a belt would likley be very pricey.

 

[MT.man]

PS proper belt deflection on most sleds would be about 1 1/4 inches. Too much deflection would cause your sled to feel like its taking off in "second gear", bad for performance. Too little defection and you get that anoying squeel at idle.

 

[Blue Dave]

What is the proper height in relation to the sheave?

Blue Dave wrote.
"The secondary clutch can be adjusted for the width difference between a new belt and a worn belt by simply adding or removing shim washers on the three bolts that act to set the sheave separation."


I am also curious on this as I just purchased a new belt, and going by my current one, it sits too low in the secondary.
Just thinking here, but if mine currently sits low, then I will have to remove washers?
I did get 3 when I purchased the sled and they are on the small side, but I assume those are them?
Should the belt not sit slightly above the sheaves on the secondary?

Thanks in advance

Usually a new belt will sit higher in the secondary clutch sheaves because it should be wider than a worn belt. Removing washers or installing thinner shim washers will cause the three bolts to spread the sheaves more which will cause the belt to sit lower. Adding shim washers under the bolt heads will cause the sheaves to be closer together which in turn will cause the belt to sit higher in the sheaves. The manual says that the top of the belt should be between 0.5 mm below to 1.5 mm above the secondary sheaves. Of course you should always confirm the correct center to center measurement between the primary and secondary clutches first. If the center to center is correct (268.5 mm) and the belt width is within range (32.5 to 34.5 mm) then you can look at the height of the belt in the secondary.

After making an adjustment to the secondary shims and re-installing the belt make sure that you run the sled on a stand spinning the track a bit and letting it roll to a stop before re-measuring the belt height in the secondary. This ensures that the secondary clutch is completely closed when you make the measurement. I like to run my belt height on the high end of the acceptable range (1.5 mm above the sheaves) because this gives a better hole shot and back shift. However because of manufacturing tolerances in the belt length you may get some belt squeal or creeping at idle with a belt which is at the short end of the length tolerance range with the height set at the high end of the secondary adjustment range. Basically I like my belt to be as tight as possible without squealing or creeping.

 

[snobill]

I just had to take shims out it was to high and squealed and the reverse didn't work a couple times and I was told it was because the belt was running to high . Adjusted and works like a charm now !

 

[Anatolievich]

Where can I find info for adjusting clutch for new belt? I checked FAQ but found nothing.
Thanks

There are none, just put the belt on.

Hello . I really liked Your avatar . You can see the photos that You have a set of lights ?
Sorry for my English.

 

[Irv]

What is the proper height in relation to the sheave?

Blue Dave wrote.
"The secondary clutch can be adjusted for the width difference between a new belt and a worn belt by simply adding or removing shim washers on the three bolts that act to set the sheave separation."


I am also curious on this as I just purchased a new belt, and going by my current one, it sits too low in the secondary.
Just thinking here, but if mine currently sits low, then I will have to remove washers?
I did get 3 when I purchased the sled and they are on the small side, but I assume those are them?
Should the belt not sit slightly above the sheaves on the secondary?

Thanks in advance

Usually a new belt will sit higher in the secondary clutch sheaves because it should be wider than a worn belt. Removing washers or installing thinner shim washers will cause the three bolts to spread the sheaves more which will cause the belt to sit lower. Adding shim washers under the bolt heads will cause the sheaves to be closer together which in turn will cause the belt to sit higher in the sheaves. The manual says that the top of the belt should be between 0.5 mm below to 1.5 mm above the secondary sheaves. Of course you should always confirm the correct center to center measurement between the primary and secondary clutches first. If the center to center is correct (268.5 mm) and the belt width is within range (32.5 to 34.5 mm) then you can look at the height of the belt in the secondary.

After making an adjustment to the secondary shims and re-installing the belt make sure that you run the sled on a stand spinning the track a bit and letting it roll to a stop before re-measuring the belt height in the secondary. This ensures that the secondary clutch is completely closed when you make the measurement. I like to run my belt height on the high end of the acceptable range (1.5 mm above the sheaves) because this gives a better hole shot and back shift. However because of manufacturing tolerances in the belt length you may get some belt squeal or creeping at idle with a belt which is at the short end of the length tolerance range with the height set at the high end of the secondary adjustment range. Basically I like my belt to be as tight as possible without squealing or creeping.

Great info Blue Dave and MT.man, guess I had better have a look at my service manual as I still don't understand where these shims go or need to be removed?

I haven't installed my new belt yet but hope to tomorrow so I will take some pics and let you guys decide if I am good to go or too high/low?

Thanks

 

[Blue Dave]

Irv,

Here are some pictures for you.

The first picture shows the plate attached to the fixed secondary sheave where the three bolt ends hit against to hold the two secondary sheaves apart at rest. You can see the three marks where the bolt heads have been hitting.

The second and third pictures show the three bolts in the secondary sliding sheave from the outside and inside views respectively.

The fourth picture shows one of the three bolts along with two spacer washers. The spacer washers are available in 1 mm and 0.5 mm thicknesses. You can mix and match the thicknesses to obtain the proper belt position in the secondary but obviously make sure that you have the same combination of spacer washers on all three bolts.

Less spacer washer thickness under the head of the bolt causes the bolt to thread in farther and consequently protrude further through the sliding shave and therefore will hold the sliding sheave further away from the fixed sheave at rest. This adjustment only effects the belt position in the secondary clutch when the sled is at rest. Once the secondary starts to open when underway these bolts have no effect whatsoever.

As your belt wears you can add shim washer thickness which will narrow the secondary sheave opening driving the thinner belt higher in the secondary clutch at rest. A new belt may require the removal of shim washer thickness to prevent belt squealing or sled creeping if the belt is too high in the secondary and consequently is too tight against the primary. It is kind of backwards of what you might think at first until you understand what the shim washers are doing.

For me I like the belt as high as possible in the secondary without squealing or creeping because this effectively results in the sled taking off in the lowest possible effective gear ratio giving the best hole shot.