1.5mm shim and purple spring

Leave the weights alone. In your setup and needs, they'll do little more than hurt your gas mileage.

Thanks for the reply, can I get the shims and purple spring at yamaha dealer? Are there specific shims and spring that fit grizzly 660?

Or would 2mm shim and purple spring be better?

Pluto75 said:

Or would 2mm shim and purple spring be better?

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I believe your machine will take 2mm. Just make sure you have spline showing when your reinstall the primary.

What size socket do I need to get the primary and secondary off of a 2003 660? And also size socket for nut to get spring off? Thank you all for your help!

Could I do a 1.7mm shim on a 660?

Pluto75 said:

Could I do a 1.7mm shim on a 660?

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Yes. You can do up to 2.0mm on a 660.

Sweet I am ordering a set of shims with two1mm ,one .5mm,and one .2mm. Think I will start with 1.7mm see how I like it. I see alot of people are happy with 1.5mm. Is 1.5mm all that's really needed?

Count your stock pulley ratio before you start adding shim, to know/feel the difference in set-ups.
I can put 2.5 mm's in my '06' 660 with full spline engagement to the cam plate. Go slow and make sure weights don't fall out during installation and the cam plate is fully engaged.

How much top end speed will I lose by adding 2mm shim? Mph?

Will a 2mm shim make the belt rub on the case?

I don't have a 660, but when I added 1.5mm shim on my bike, I lossed aprox 5 - 6mph.

Pluto75 said:

Will a 2mm shim make the belt rub on the case?

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Only with a belt worn close to the wear limits. A new belt will not rub the case at 2.0mm on a 660.

Is it ok to put 3 shims? I have a 1mm,.5mm,and a .2mm.

Pluto75 said:

Is it ok to put 3 shims? I have a 1mm,.5mm,and a .2mm.

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I use 3 shims to get to 2.5 mm's, 2) 1 mm shims and a .5 mm shim.
Just make sure there is full engagement of the cam plate to the shaft splines.

Does your belt rub the case with 2.5mm?

How much top end did you lose using 2.5mm? I want to go 2mm but don't want belt to rub. What happens when belt rubs?

Pluto75 said:

How much top end did you lose using 2.5mm? I want to go 2mm but don't want belt to rub. What happens when belt rubs?

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I don't remember how much top end speed was lost, but I solved that by cutting the cam plate and resetting the angle.
As for belt rub, that didn't occur until over a 3 to 1 ratio was achieved. I can run a 3.54 ratio and as the ratio increased I slowly wore (rubbed) the belt into the cover.
My set-up is in the signature showing the combination of C.V.T. mods I use for the high ratio.
I started with shim, then added a machined primary, then narrowed a belt and then turned down the diameter on a set of weight covers. I now use all the mods listed, in combination.

What will my ratio be if I add 2mm shim?