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EPI clutch kit plus 1.5mm shim

4K views 28 replies 9 participants last post by  Travis 2021 Grizzly 
#1 ·
Hey all, I have a 2021 grizzly 700 and I already have 1.5mm shims in and purple spring, I ordered the EPI sport utility clutch kit and was wondering if anyone has had any belt slippage or issues with this set up ? I was debating taking the shims out cause it could possibly cause belt slippage with the clutch kit. I’m running 26 ITP Mud lights but intend to go to 27s.
 
#2 ·
If you already have the shims and a purple spring, why order an epi clutch kit? What are you looking to gain from what you have now?
 
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#3 ·
I have a buddy that recommended the clutch kit but doesn’t seem to recommend the shims to go along with it. I’m after lots of torque and pep don’t care for top speed. (Make up for heavy tires and two up) I do a lot of trail riding two up and my trails tend to get muddy but I’m not into hardcore mudding just sometimes can’t avoid it. From what I’ve read the clutch kit will increase my clutch engagement and the shims I know give you more low end torque with loss of top speed. I enjoy the increased low end in high gear the shims give. Does the clutch kit act the same as adding the shims ? Sorry green horn with all of this stuff !
 
#4 ·
The epi clutch kits don t do anything to increase the initial low end torque. Shims on the other hand to exactly that. They start you in a lower gear sorta speak

They epi kits also generally come with stall springs which bring up the wet clutch engagment , this is ment to give more off the line snap but also has a tendency to burn up the wet clutch which is a bad thing..

Most on this forum will suggest you stay away from the EPI kits as they are over priced ...

What you chose is up to you, but bang for buck the shims and purple spring is already a good start.

If you want more low end torque , a coop machined sheave is the next step in my and many others opinion.
 
#6 ·
If you want to experiment a little and mix and match give her a shot, and report back your finding. It s your machine so do what makes you happy.
 
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#9 ·
The E.P.I. kit you ordered is worthless for what you want, the shim raises the pulley ratio which magnifies/multiplies the torque produced so.....
The COOP machined primary movable sheave is like adding shim, it raises the pulley ratio and magnifies/multiplies the torque even more.
Look in my signature for the c.v.t. mods I run, I raised the pulley ratio to the max, then added other mods for increased forward bite and higher m.p.g.
 
#11 ·
:)
We are trying to save you the time (wasted time) of installing the kit for nothing you want.
The kits are for those that are looking for better but don't know/understand how the c.v.t. system works. I say work, as each part in the system effects the other parts in the system, its a relationship deal and.....
The deal 'IS' a high pulley ratio is great for out of the hole pull...and COOP was the first to offer Mod 1, the shim mod. As time when on members wanted more from their systems and COOP realized the linear effect of shim so worked on another part in the system, the cam-plate.
His mod #2 is a cut cam-plate which leaves the ramp angle the same at the bottom ( the stock angle) and his bend starts part way up the ramp so the shim effect is felt at take off, then as the weights hit the new ramp angle from mod #2 under greater force, the shim mod effect is reduced to restore the top speed lose from the shim mod.
E.P.I. sells to those that don't understand the Yamaha c.v.t. system, if we can help let us know.
 
#13 ·
Return that epi kit, use that money towards a coop mod 3. You will be much happier. Those kids are a waste of money, not to mention, you can purchase all parts of the kit separately for less than the kit.
But that kit is not what you are looking for. Go with the shims and the purple spring, and direct you buddy to these forums and google to educate himself on cvt systems.

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#14 ·
He has an EPI clutch kit installed and likes it’s a lot, he has nothing against the shims but thinks it will cause belt slippage from the primary engagement if I run the shims and the clutch kit. I was looking at returning the kit but I opened it to see what colour spring it came with (cut the sticker seal) so not sure they will take it back.
 
#15 ·
Personnaly I m super impressed how tuned the clutching is on 2019 grizzly right from the factory.

The only thing i changed is my movable primary sheave is a coop machined sheave which I had on my privious grizzly.

My initial cvt ratio is 2.95:1 vs stock 2.45:1....Still running stock weights and spring. It turns my heavy Growlers tires with authority . I ve racked up 3800kms on this set up

I did try the purple spring early on but found the extra reving while accelerating normally was annoying. 3 days later, I went back to stock spring, and never looked back.
 
#17 ·
Kind of a crappy return policy if you just opened it and didn't install.
I have a 2021 as well with a Coop Mod#3 and a shim. I like bottom end. I still can run 60mph, although I don't do that very often. When you get the Coop sheave it's like adding somewhere around 3mm of shim due to his machining. Well worth the money spent for bottom end power. I mailed mine (sheave) to him and was back in less than a week. Just call and talk to him, he's a great guy and extremely knowledgeable. I had his Mod#3 on my 2013 and put over 8000 miles trouble free and was great. I did put in a purple spring (2013 &2021) to help me with backshifiting and engine braking. But that was only around $35 for the Spring.
 
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#22 ·
If you are going to do any mod to your Griz then Arnie's machined sheave and secondary spring is the only way to go, EPI clutch kit is a waste of money and time sorry to say, remember you only have 50hp to work with you just have to know where to put the power were its needed to make a gain, Coops mod 3 package does this for your Griz hands down, you also can add .5-.7mm shim for more bottom end with Coops machine sheave setup just take note of belt rub on your sheave covers, you will loose a bit top end with the extra shims, 7200km on my Griz with Coops mod 3 and purple spring with .5mm shim, glad I bought it and has worked flawless.
 
#24 · (Edited)
Prob best move these guys on here and gals are the best techs u will find and real info they are great at spending our money (not a bash) i did shim mod spring had the boys do the shopping i got it all and they helped me with my first cvt service ever shim mod epi spring all sort of stuff i was paying a shop for with that said trust them they are greatest
 
#25 ·
Prob best move these guys on here and gals are the best techs u will find and real info they are great at spending our money (not a bash) i did shim mod spring had the boys do the shopping i got it all and they helped me with my first cvt service ever shim mod epi spring all sort of stuff i was paying a shop for with that said trust them they are great an wouldnt tell ya fact
Exactly. We were all at the learning stage at one time.
Is the best way, be guided with knowledge, learn yourself, get good, and pay it forward. These forums are great for that.

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#28 ·
Another aspect of a high pulley ratio from shim(s), machining or a narrow belt I haven't read in this thread is there is less strain put on the wet-clutch assembly at take-off near the engine engagement r.p.m. of the wet-clutch shoe springs.
This happens because torque is the engine power used to get a load moving (whether coming out of the hole hard during normal riding or pulling a heavy load as pictured above) and the higher ratio from c.v.t. mods. lets the engine r.p.m. increase more over the stock pulley ratio. This increase in engine r.p.m. at take-off from zero ground speed provides greater lock-up pressure sooner in the wet-clutch drum to reduce slipping between the shoes and the drum.
Does everyone need this? No.....or not in most daily riding situations but.....in the game of changing the pulley ratio just in case of need I learned I can work the system much harder when needed with great results.
To take this game of c.v.t. mods to the next level after shim/machining mods I learned the stock 660 secondary spring rate was less than needed so....after a few different springs I learned the E.P.I. purple spring was the best choice because I didn't want more spring rate which puts other parts in the drive-line at risk.
With the purple spring there is no slip during 99% of my time on the trail(s), but every now and then I can get the bike bound up and with to much throttle the belt can be heard lightly chirping inside the cover. It is in one of these situations I get out the winch cable to ride on. I feel if I had a heavier spring I might break an axle, then be stuck with a bigger problem.
Also I want to point out your best set-up depends greatly on the tire diameter you run. I feel the 26.5" tall true size is best for the Grizzlies c.v.t. system so take this as a guide only. This is based on my trail conditions which are not like some other members around the world.
As for expense, those of us that enjoy the higher ratios already know the expense :) so know when we recommend a mod the recommendation(s) comes from our riding experiences. These experiences may be varied, so for me the benefits are an easier machine to handle when out on the trail.
Around here a day ride can be well over a hundred miles which is a long way past the range of a stock machine's fuel capacity. In the stock configuration, to go this distance or more in a day with no access to a town (gas pump), the addition of an extra fuel tank is needed which then changes the balance of the machine. C.V.T. mods can greatly increase the range of a Grizzly on one tank of gas which I like.
A few years ago 3 other members of G.C. met me in my local area for a few days of riding. The first to arrive was here for a Y.O.L.O. trip and we had spent the previous 9 months planning for his arrival and spent his first two days here getting him use to the area trails and double checking his 700 c.v.t. set-up for our third long day out on the trails. Our goal that day was ride two Grizzlies 500 miles each without using a gas pump or fuel dump placed earlier. We had to carry everything we needed for the day from camp. We did 455 miles that day while relying on c.v.t. mods to raise the fuel range of a tank of gas by lowering the cruising engine r.p.m.
Then while gone that long day, the two others members met us in camp for 4 more spectacular days on the local trails, and over 7 days the first member to arrive and I had done 978 miles.
Having a well behaving machine was nice, so at the end of each day we could get ready for the next day out.
C.V.T. mods are not needed by all so let me point out to new members while going back through old threads, look for how many members remove c.v.t. and what those mods are and the reason for removal.
 
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