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2021 Grizzly 700 Xtr, K&N Filter, 27" zillas
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Just got a 2021 Grizzly 700 Xtr on Tuesday. I looked hard and long and finally found one.. Drove 4 hrs each way to pick it up.I searched this forum and still not sure on a few mods I wanna do. So here goes, I installed a K&N air filter and Im wanna also install a fuel programmer with a set map. Just not sure what brand to buy?
Next, id like to instal a clutch kit to get a little more low end and help turn the 27" zillas that came on it and dont know where to begin. She feels a little sluggish. Also dont know what brand and what parts? Shim,spring,weights and etc. Im very mechanically inclined just will be my first time doing clutch work. Any help is greatly appreciated. Thanks
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Epi clutch parts. It should turn them 27 pretty easy i am sure ridgeway will chime in on the cvt stuff he knows alot about alot along with 98 % of the guys and gals here i am not included lol congrats drive her like u stole it
 

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For increased low end pull, raise the pulley ratio. Most start with shim, if your '21' is like previous years, start with shim. 1.5 mm's max. I suggest counting your stock ratio before removing the primary, to know the amount of change. No kit needed, look here for the shims.
See if Arnie Cooper can mail you a couple shims.
Of more is needed later, look into having him machine the moveable sheave to raise the ratio further. You can run .5 mm of shim in combination with the machined sheave.
Then if the belt slips add a purple secondary spring.
Some want to do everything at one time, I don't recommend doing more than one mod at a time.
 
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I agree with Ridgeway on Coop45 machined sheave.

I have the same bike as you, but 2019 and the stock weights and spring work very well. I have the addition of the Coop45 machined sheave witch allows you 25% lower cvt ratios with zero top speed loss.

The stock stuff and machined sheave work amazing on my 2019. I believe the 21s (same spec's) would respond accordingly
 
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2021 Grizzly 700 Xtr, K&N Filter, 27" zillas
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Discussion Starter #5
I agree with Ridgeway on Coop45 machined sheave.

I have the same bike as you but 2019 and the stock weights and spring work very well. But I have a coop45 machined sheave witch allows you 25% lower cvt ratios with zero top speed loss.

The stock stuff and machined sheave work amazing on these 19 to 21 grizzlies
Dumb question, Whats a sheave?
 

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Dumb question, Whats a sheave?
:)
Nothing dumb about asking....
:)
The Yamaha c.v.t. belt system has two pulleys, each with two sides/pieces. Each side of each pulley is called a sheave. On the from pulley, the inside sheave is fixed to the shaft splines and held tight by the collar the movable sheave rides across. The collar is held tight by the cam plate and nut, and the cam plate is turned by engaging splines on the shaft end.
The cam plate is fixed tight in place, and has ramps the weights side on, up and against the movable sheave held tight by the belt through the secondary spring.
Arnie machines the movable sheave face, changing the angle for more ratio at the center of the sheave, and the changed taper gradually reduces the the amount of material removed for a stock ratio at higher speed.
The material removed lets the belt ride lower in the pulley thus less belt contacting the sheaves on the front pulley, and as the belt is a constant length, the amount of belt not on the front pulley at take off is now taken up on the secondary (back) pulley.
This changes (increases) the number of times the front pulley turns for one turn of the rear pulley, like installing a smaller front sprocket on a dirt bike for more low end pull, by magnifying the engine torque produced near idle.
Here is a video of the system working and the parts moving though out the range of motion.
 

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Discussion Starter #7
:)
Nothing dumb about asking....
:)
The Yamaha c.v.t. belt system has two pulleys, each with two sides/pieces. Each side of each pulley is called a sheave. On the from pulley, the inside sheave is fixed to the shaft splines and held tight by the collar the movable sheave rides across. The collar is held tight by the cam plate and nut, and the cam plate is turned by engaging splines on the shaft end.
The cam plate is fixed tight in place, and has ramps the weights side on, up and against the movable sheave held tight by the belt through the secondary spring.
Arnie machines the movable sheave face, changing the angle for more ratio at the center of the sheave, and the changed taper gradually reduces the the amount of material removed for a stock ratio at higher speed.
The material removed lets the belt ride lower in the pulley thus less belt contacting the sheaves on the front pulley, and as the belt is a constant length, the amount of belt not on the front pulley at take off is now taken up on the secondary (back) pulley.
This changes (increases) the number of times the front pulley turns for one turn of the rear pulley, like installing a smaller front sprocket on a dirt bike for more low end pull, by magnifying the engine torque produced near idle.
Here is a video of the system working and the parts moving though out the range of motion.
[/QUOTE
Hey ridgeway thanks for all that info. Coop is recommending a gold spring to go with the sheave job. Does that sound correct to you? If so where do I order one and find instructions on how to change that myself? I know I may need a spring compressing tool....correct?
 

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Discussion Starter #8
Its not that I im questioning coop and his work. I just like to get as much info on something to make a sure Im going the right route.
 

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I used a not safe spare tire to balance on and remove that secondary spring nuts
 
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Hey ridgeway thanks for all that info. Coop is recommending a gold spring to go with the sheave job. Does that sound correct to you? If so where do I order one and find instructions on how to change that myself? I know I may need a spring compressing tool....correct?
I would use a purple spring, most members don't ride deep thick mud to need the extra clamping force of the gold spring.
The belt tension is a weak point in the drive line from the engine crank to the tire patch. The purple spring handles the extra torque from the higher ratio under open trail conditions, and I want the belt to slip if stuck in deep mud before the axle breaks. That is the time to use a winch, and once I was jumping a snow back and came down on one rear axle with a littler throttle applied and broke an axle with the purple spring anyway.
I get my springs here;
And do not let these guys talk you into any kit, just a spring for now, and if you want to get fancy, maybe a set of weights later.
You will want a wood vise to hold the primary, it is easy to build yourself.
Then you will want a tool to hold the secondary, one can be made from scrap cold roll iron plate.
As for a spring compression tool, many use a wheel off the machine, the center hole goes over the nut, you get someone to push down (sit on the wheel) to compress the spring to get the nut off, and back on.
When I take a nut off, I use an impact and wrap a towel around the socket to catch the nut.
Its not that I im questioning coop and his work. I just like to get as much info on something to make a sure Im going the right route.
COOP will also sell you a spring, I would go that way if you use his machining service which I HIGHLY RECOMMEND!

The secondary spring has great effect on the back-shift rate to slow the machine and is engineered for the stock machine using stock tire diameter. The stock spring is engineered to be a weak link in the drive system to prevent axle breakage, and the tension by the secondary spring is the key to Yamaha's successful c.v.t system using a wet-clutch.
Changing the tire diameter changes the back-shift rate, so when we add c.v.t. mods to magnify the engine r.p.m. torque at near idle speed, the stock spring is too weak for some members in their local trail conditions.
I also want to point out how sensitive the system is to small changes. Notice the spring rate table, and the difference in the orange spring thought to be equivalent to a stock 700 spring, and the purple spring.
My purple spring going down a steep steep trail will cause the bike to slide to a stop in two wheel drive, requiring a little throttle to prevent stopping. In 4x4 there is enough tire pulling to prevent this sliding.
I would not want too much secondary spring myself.
If you use COOP have him add 1) 1 mm shim and 1) .5 mm shim to your order.
We'll get to cutting the cam plate and adding heavier weights later. I use these mods for higher m.p.g. by less engine r.p.m.'s when cruising above 20 m.p.h.
(all this can be done to a 550 too)
 

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@GrizzlyXTR

It's always best to do one mod at a time so you know what changes effected what..


I have the same bike as you and did like everyone else and installed the epi purple. I was not happy with all the extra reving when accelerating from a dead stop . Went back to stock spring 3 days later.

Coop45 sheave is the best mod for off the line torque gains! I LOVE mine!!!!
I'd suggest you wait an accumulate some mileage before changing the spring or weights as to give you time to get a feel for things.
 

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wow.... Thanks guys for all this information. My head is spinning a bit, but I mostly understand now how it all works and what each clutch does. I think when the snow flys here, I will send my sheave to coop and reassemble and put some time on it. Then decide if ill need the purple spring. Thanks again!
 

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Does the shim take the belt out of alignment and cause more wear? Should I do the shim with the machined sheave? Or wait after a few rides?
 

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One last thing, shim or machined clutch first? I know im annoying! Lol
 

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Does the shim take the belt out of alignment and cause more wear? Should I do the shim with the machined sheave? Or wait after a few rides?
Shiming does not cause misalignment problems. You can add a 0.5 mm shim to a machined sheave if you'd like. But it's not required

I've racked up 1200 miles on my 2019 Grizzly, utilizing Coops machined sheave, stock weights and stock spring. No shim. and I couldn't be happier with it. I suggest you try the same and go from there.
 
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Discussion Starter #16
Shiming does not cause misalignment problems. You can add a 0.5 mm shim to a machined sheave if you'd like. But it's not required

I've racked up 1200 miles on my 2019 Grizzly, utilizing Coops machined sheave, stock weights and stock spring. No shim. and I couldn't be happier with it. I suggest you try the same and go from there.
👍👍👍, will do! What does a shim do?

Also what kind of riding do you do?
Im 20% mud and 80% hard pack trails with some steep hills.
 

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Does the shim take the belt out of alignment and cause more wear? Should I do the shim with the machined sheave? Or wait after a few rides?
:)
The belt is flexible and in stock configuration the pulleys cause a side pressure as the pulleys move. The primary pulley pushes from the outside causing the belt climb out/up of the pulley causing a greater circumference of belt contacting the pulley, resulting in less belt contacting the secondary pulley. As the belt climbs out of the primary, the secondary pulley spring is forced to collapse inward allowing the belt to work deeper into the secondary proving more belt length in the primary pulley.
Adding shim, which I did first when learning how this system moves, did not cause additional wear to the pulley faces.
The reason for machining is the limit to how much shim can be added to the primary pulley shaft. My 660 will hold 2.5 mm's, and due to the design of the primary cage, the limit for shim in my 660 is the amount of spline which the cam plate engages.
With your 700, the amount of spline is not the limiting factor with the grease cover installed, the limit for the 700 is the grease cover screws rub the cage before max shim is installed.
Machining is another way of providing more room for the belt in the primary, for increasing the pulley ratio for more magnification of low engine r.p.m. torque.
I learned the system, maxed out the amount of shim installed, then wanting more feel-good had COOP machine my primary.
I installed the machined primary, learned the effects of this mod, and how the belt placement changed in the secondary. Then I started adding small amounts of shim in combination with the machined sheave until I reached the limit of the belt higher in the the secondary at take-off. I slowly rubbed the belt in by adding more shim until I almost had the belt out of the primary. Your 700 has less room for the belt to ride out of the secondary, so 700 owners use less shim with machining than 660 owners.
If you want to learn how different mods affect the system, do shim alone first. Then do the machining, then add shim later, then the belt slips due to your thumb, add a heavier spring.
Ove time we learned machining can be done safely, so recommend this to others, knowing they want the end result without all the labor to learn each step.
To get your best set-up, its not what you ride in, but how you ride across it, or want to ride across it and how responsive you want your bike to react.
I like the fast reaction for the greater torque with less throttle movement. In big rocks my 660 easily climbs with very little throttle movement, I raised the pulley ratio to max for my bike, and when cruising at moderate speed I can tap the throttle and carry the front end over a water puddle or up on a rock rock ledge.
As for other mods I run, once I got the ratio maxed out, I realized I had the additional power snap to change the weights and add a cut cam plate to lower engine r.p.m.'s for cruising and lower fuel consumption. Its all about keeping the engine in the best torque range for your trail conditions, the techniques of c.v.t. mods work for all, but you might need different mods for your conditions.
 
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I had to search 5 states to find the SE I’m picking up Saturday. Besides the winch (i had installed) whats the differences between the XTR and the SE ? And is there any specific break in tips other than dealer suggestions ? Going from Polaris 850 scrambler to this grizzly hope im not too disappointed in the significant hp loss-
 

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Ride it like you will, and vary the engine r.p.m.....no constant w.o.t.
Also, heat cycles help parts wear together.
 
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