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Discussion Starter #1
I have added a 2mm shim and a purple spring to my 2003 grizzly 660 with 27" tires. It gave me my low end back. Mid range power seems to be lacking a little tho. If I were to put lighter weights in the primary, would that give more mid range? Would like to get the snappyness in mid range power. Any and all info would be greatly appreciated. Thanks all
 

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Yessir, and you went about it the right way by doing shim first, before weights. Do you know for sure you currently have the stock weights in? Lighter weights will definitely do what you are trying to accomplish. For lighter weights, go all of the same weight. Don't mix and match.
 

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If you liked the mid-range before the shim, cut the cam plate.
 

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Discussion Starter #4
Yes I'm pretty sure it has original weights,I bought it from a freind with 750 miles on it. I have read a couple threads that it revs real high when you put in lighter weights. Would higher rpms be an issue?
 

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Discussion Starter #6
From another thread It was recommended by a knowledgeable member to use 8 16gram weights.
 

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Discussion Starter #7
I am also thinking of using bel ray waterproof marine grease. It's alot cheaper than yamaha ultramatic grease. Is that a "good idea " or not?
 

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Cutting the cam plate allows you to change the timing of when (what engine r.p.m.) the weights force the movable primary sheave against the belt. I do it to keep the forward bite at the top of the torque curve.
Lighter weights will make the engine run at higher r.p.m.'s at lower ground speed, reduce top speed greatly and kill the range on a tank of gas. I know as I tried littler weights.
I use high temp marine grade grease and it works for me.
There are dozens of threads on C.V.T. mods, go back 2 to 3 years to find them and read on C.V.T. theory and how individual mods affect certain aspects of C.V.T. power transfer/application.
 

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Pluto75, please tell us what speeds you consider as mid power range. Makes a difference if you need more clutching or more ponys.
Also what is your top speed now?
 

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I am also thinking of using bel ray waterproof marine grease. It's alot cheaper than yamaha ultramatic grease. Is that a "good idea " or not?
I've been running it for about a year. It's held up alright. I'm switching back to Ultramatic when I do my tear down next week though. It has been flung out of the sheave more than once, but I can only image my setup gets pretty hot running 30's in deep snow haha.
 

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If grease is found outside the primary, check the o-ring seal for nicks. I've had to replace a couple o-rings that didn't fully seal from being pinched.
 

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Not real sure on top speed, I would guess mid range 25/30mph.
With 2mm shims and a purple spring changing to 16g weights might have it revving way to high for trail riding.
Personally I usually lean toward heavier weights. With your setup I would try going back to the stock spring just for a test. It is a fairly big jump going to a purple spring from a stock 660 spring... stock 160/280lbs vs purple 195/315lbs
 

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It is a fairly big jump going to a purple spring from a stock 660 spring... stock 160/280lbs vs purple 195/315lbs
I agree on this one. Even going from the stock 550/660 spring to the slightly weaker then purple orange spring (190/310lbs ) was a big jump on my 550. Noticibly more reving. Don't really remember a flat spot in the power band afterwards.

In my case Pluto75 I added heavier weights to control the reving. I find my power seems fairly leniar with this set up. Not saying it's what you necessary need to regain mid range power though , just that it worked out for me.
 

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With 2mm shims and a purple spring changing to 16g weights might have it revving way to high for trail riding.
Personally I usually lean toward heavier weights. With your setup I would try going back to the stock spring just for a test. It is a fairly big jump going to a purple spring from a stock 660 spring... stock 160/280lbs vs purple 195/315lbs
I agree on this one. Even going from the stock 550/660 spring to the slightly weaker orange spring(190/310lbs) was a big jump on my 550. Noticibly more reving. Don't really remember a flat spot in the power band afterwards.

In my case Pluto75 I added heavier weights to control the reving. I find my power seems fairly leniar with this set up. Not saying it's what you necessary need to regain mid range power though , just that it worked out for me.
I agree with these guys as well. Just cause I responded earlier about the weights being the right thing to change for the mid speed adjustment, DOESN'T MEAN YOU SHOULD go lighter. I even went with heavier weights on my 450. It's not as peppy as it used to be, but that is from the heavier tires I put on it. With the 18 gr weights (stock is 14 on the 450), it does a way better job of keeping it in the meat of the torque, which is where the Grizz's shine.
 

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Discussion Starter #16
I do like the set up with purple spring and 2mm. It doesn't rev high now. I might just leave it the way it is. Was just looking for a little more mid range, but don't want to have it reving real high.
 

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I agree on this one. Even going from the stock 550/660 spring to the slightly weaker then purple orange spring (190/310lbs ) was a big jump on my 550. Noticibly more reving. Don't really remember a flat spot in the power band afterwards.

In my case Pluto75 I added heavier weights to control the reving. I find my power seems fairly leniar with this set up. Not saying it's what you necessary need to regain mid range power though , just that it worked out for me.
No flat spot might be a result of FI

I agree with these guys as well. Just cause I responded earlier about the weights being the right thing to change for the mid speed adjustment, DOESN'T MEAN YOU SHOULD go lighter. I even went with heavier weights on my 450. It's not as peppy as it used to be, but that is from the heavier tires I put on it. With the 18 gr weights (stock is 14 on the 450), it does a way better job of keeping it in the meat of the torque, which is where the Grizz's shine.
Ty.. you may remember that I installed 660 weights in the 450 my Queen use to ride. Made the 450 a much better trail riding machine. Like night and day.


I do like the set up with purple spring and 2mm. It doesn't rev high now. I might just leave it the way it is. Was just looking for a little more mid range, but don't want to have it reving real high.
Adding the shims increases the low end torque but you lost 4-8 mph top end. You may not hear it but the engine is revving higher at a lower ground speed. The load of that spring will hold the CVT in the taller gear ratios until the engine can build enough hp to over come the force of the spring. The HP increase is not linear this means that it may fall on it's face during a certain band of rpm's.
If the flat spot really bothers you. If you machine is properly tuned. As experiment and to save the cost of the weights for now, consider going back to the stock spring. It may move the power flat. spot to a place that you may not notice.
 

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Ty.. you may remember that I installed 660 weights in the 450 my Queen use to ride. Made the 450 a much better trail riding machine. Like night and day.
Yessir I remember exactly. Your experience with heavier weights in the 450 is what convinced me to do the same in mine. No regrets whatsoever.
 
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