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Discussion Starter #1
So I have been reading as much info as I can find on how to improve on the power/torque to the wheels. ( I'm a sled guy and know lots about CVT's)
So it's pretty obvious to anyone that drives say a 500 zuk w a standard shift and then rides a bike with a CVT that some power is lost to the CVT.
I have bought the shims , 1mm and .5mm and From what I have read it sounds like slugs in the wet clutch would be worth it. Is the purple spring in the secondary still the thing to do?
Bike is 2015 grizzly 700 with 27" Zilla's. We mud mostly some trail . I dont need to go 62mph. I would like to do wheelies
 

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Welcome to GC. Depending on how much you want to spend, there's a couple routes you can take. The shims are the cheapest route. Most can safely run 1.5mm of shim, others run a max of 1.7mm of shim. You have to watch for the belt rubbing the cover on the secondary, and cage clearance. It'll rub through the belt cover with too much shim. You lose top end speed, but will gain a lower ratio and more bottom end snap.

The other route, which is the way I eventually went, is to get a milled primary sheave. COOP45 did my milled sheave, and it gives you the benefits of a lower ratio, but with no top end loss. I tossed in a .5mm shim with it, as it's all he recommended to run. Can't remember price, but it was in the $200-300ish dollar range I think. You can PM him and ask.

I used a purple spring with both setups. I'm jumping up to a gold spring on my top end rebuild. The main reason being, I have 30" Mudder Inlaws, and the tires alone weigh 49lbs each. I want a little stiffer spring for my riding style and extra heavy tires. The purple should work good for your 27's.

I'm adding the wet clutch slugs, based on the recommendation of others on here that make big HP, in order to help preserve my wet clutch. I'm doing a high compression piston on top of all my other mods, the slugs will be a new addition for me, so I can't give any feed back yet on those. I hear it'll engage at a lower RPM with those in there. It's not necessary unless you're doin BBK's or making a lot more power over stock.

Good luck with your build. Feel free to ask others on here as they will be more than happy to help you spend your money lol.
 

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Well after reading 20 pages of the 3.45 ratio might have to try the 19G3450 belt.
Ya I read that thread to lol. I think after I upgrade and add the slugs and gold spring, I'll be about done with clutch mods. That's why I'm going with a higher compression piston and looking for a better cam.
 

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I have a set of wet clutch slugs ready for install.. I'm a bit nervous of the whole job. I know its just parts, but its a fair amount of work. The videos on youtube are pretty good. Guess I'm just lazy. ha..
I don't like having my wheeler down at all. I have a kid in hockey so I'm Hell'a busy with that. I'm scared I'll only get it 1/4 done one day 1/4 done another then forget a step due to the time lapse, plus my wheeler will be down until I finish. I ride it often, as I can leave right from my garage and ride my own land.

When I do install, I will do a post on the results.
 

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So I have been reading as much info as I can find on how to improve on the power/torque to the wheels. ( I'm a sled guy and know lots about CVT's) I have bought the shims, is the purple spring in the secondary still the thing to do?
Bike is 2015 grizzly 700.
C.V.T. mods. change the way engine power is applied to the transmission, and the transmission on a grizz is like a drive/overdrive gear box on a truck.
The stock grizz comes with a tame pulley ratio suitable for the the average rider and the ratio can be changer.
You asked several question in your original post, about shim and slugs and spring, so here is my take on your questions.
I don't think slugs are beneficial for most riders. Changing the engagement r.p.m. of the wet clutch shoes is not as important as changing the pulley ratio so that when the wet clutch engages the engine has the ability to turn the pulley with the available engine torque produced.
I learned to raise the pulley ratio with the stock wet clutch and 26.5" true tires and to do this I started with shims. My 660 will hold 2.5 mm's of shim but most 700's only accept 1.7 mm's max without cage modification. I found with 2.5 mm's there wasn't enough improvement so I had COOP machine the movable sheave which produced the benefit equal to around 3 mm's of shim on low end, and with the new taper angle to the belt face there was no change of top ground speed when the belt reached the out edge of the primary pulley.
I run a stock belt, and with the 2.5 mm's or the machined primary individually I experienced no belt rub.
Once I learned what the machining did for my low end performance I started adding shim with the machining for even better low end pull. Once I got over a 3 to 1 ratio the belt started to rub slightly, but I learned a little rub was not bad as long as the belt didn't rub clear through the cover.
I should add I added a purple spring early on and found it was the best for my application. I recommend using the lightest spring tension that keeps the belt from slipping.
From 3.1 to 1, I starting rubbing the belt in by slightly raising the ratio, I was able to get to 3.54 to 1, but remember I run a 660 which is know to have more room to play with (cover thickness). I have install enough mods. to get to a 3.75 ratio with the cover off but did not try to run that ratio on the trail. I learned with stock 660 axles anything over the 3.54 broke axles, so I stopped there.
Most members have stopped 700 C.V.T. mods around 3.1 to 1 and use a purple spring. That is the point they don't want to chance rubbing a hole in the cover.
Once you get there, engine mods can help.
 

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C.V.T. mods. change the way engine power is applied to the transmission, and the transmission on a grizz is like a drive/overdrive gear box on a truck.
The stock grizz comes with a tame pulley ratio suitable for the the average rider and the ratio can be changer.
You asked several question in your original post, about shim and slugs and spring, so here is my take on your questions.
I don't think slugs are beneficial for most riders. Changing the engagement r.p.m. of the wet clutch shoes is not as important as changing the pulley ratio so that when the wet clutch engages the engine has the ability to turn the pulley with the available engine torque produced.
I learned to raise the pulley ratio with the stock wet clutch and 26.5" true tires and to do this I started with shims. My 660 will hold 2.5 mm's of shim but most 700's only accept 1.7 mm's max without cage modification. I found with 2.5 mm's there wasn't enough improvement so I had COOP machine the movable sheave which produced the benefit equal to around 3 mm's of shim on low end, and with the new taper angle to the belt face there was no change of top ground speed when the belt reached the out edge of the primary pulley.
I run a stock belt, and with the 2.5 mm's or the machined primary individually I experienced no belt rub.
Once I learned what the machining did for my low end performance I started adding shim with the machining for even better low end pull. Once I got over a 3 to 1 ratio the belt started to rub slightly, but I learned a little rub was not bad as long as the belt didn't rub clear through the cover.
I should add I added a purple spring early on and found it was the best for my application. I recommend using the lightest spring tension that keeps the belt from slipping.
From 3.1 to 1, I starting rubbing the belt in by slightly raising the ratio, I was able to get to 3.54 to 1, but remember I run a 660 which is know to have more room to play with (cover thickness). I have install enough mods. to get to a 3.75 ratio with the cover off but did not try to run that ratio on the trail. I learned with stock 660 axles anything over the 3.54 broke axles, so I stopped there.
Most members have stopped 700 C.V.T. mods around 3.1 to 1 and use a purple spring. That is the point they don't want to chance rubbing a hole in the cover.
Once you get there, engine mods can help.
Excellent explanation of your clutch set up. The more I read about the Cooper mod the more interesting it becomes.
 

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Excellent explanation of your clutch set up. The more I read about the Cooper mod the more interesting it becomes.
As far as I know, COOP (Arnie) was the first to start machining Yamaha primary sheaves and know's his stuff. Give him a call and he will answer your questions.
 

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As far as I know, COOP (Arnie) was the first to start machining Yamaha primary sheaves and know's his stuff. Give him a call and he will answer your questions.
Thanks Ridgway!?
 

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Update...

I put the clutch slugs in..
WOW!!!
What a huge difference.
When the machine is cold and idling higher it’s a bit sticky to put in gear and it almost creeps a bit. After 30 seconds or so my idle is a tad lower and no creep or shifting stickiness.
Throttle response is INSTANT.. like just breathe on the fun lever and the machine moves.
The grizzly stands up off the line every time I smash the throttle, but can creep away like a snail if it want to.
I have not woods trail tested yet. Just back yard tests.

It wasn’t that hard to install... the gasket surface cleaning was the biggest pain in the butt.
Also. You’ll need a 27mm or 1 1/16” deep socket to remove the wet clutch nut. REVERSE threads, don’t forget,
Hunterworks sells the new nut with the slugs and gasket kit.. I don’t see why it’s needed. It has a punch tab to stop it from backing off,,, but since I had the new nut I used it.




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The slugs are in. I tried to copy my post from another thread but It somehow linked the whole thread. Oops, sorry.


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The slugs are in. I tried to copy my post from another thread but It somehow linked the whole thread. Oops, sorry.


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Do you by any chance have a link to where you bought the slugs or know the manufacturer? have a 1.5 shim in and it isn?t enough to satisfy me as I know the bike is capable of much more. With the slugs, do you lose top end?
 

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The slugs only affect the bottom end engagement. Not necessarily any ratio, just how quickly and how firmly the clutch seems to engage. There was no top and loss as it doesn’t affect your belt ratio in anyway. I bought the clutch slug kit through Hunterworks for $49.99 and added the new retainer nut to my order for $8 or $9 more.
I really don’t think the note was needed, as it has a pinched her up at the end that goes in a groove on the shaft so it is not likely to ever come off. But I didn’t want to take any chances.


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With the clutch slugs the clutch engages if you just breathe on the throttle. When the engine is cold and idling slightly higher than normal due to the cold idle circuit there is almost a little creep in gear and the shifter is a little hard to move. When the engine is warm in the idol is at its low point the clutch is not engaged in anyway. But like I said, if you simply breathe on the throttle it engages.
On the weekend, I was towing a small trailer load of firewood in low range at 3 to 4 km/h or roughly 1 to 2 mph. It was creeping along just like a Honda in first gear.


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With the clutch slugs the clutch engages if you just breathe on the throttle. When the engine is cold and idling slightly higher than normal due to the cold idle circuit there is almost a little creep in gear and the shifter is a little hard to move. When the engine is warm in the idol is at its low point the clutch is not engaged in anyway. But like I said, if you simply breathe on the throttle it engages.
On the weekend, I was towing a small trailer load of firewood in low range at 3 to 4 km/h or roughly 1 to 2 mph. It was creeping along just like a Honda in first gear.


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Does your machine achieve wheelies by just hammering the throttle, with my shim i cant seem to get the wheels up more then an inch or two without tugging on the bars


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We all must be getting old, a clutch thread going on this long and no fights yet. Lol.
 
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^^^ haha


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Mine wheelies easily. Pin it and it points to the sky .
I have a machined sheave, but shims worked just as well.
I have an EHS fuel controller and muffler tip mod.


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Discussion Starter #20
Sounds awesome! I’m going to order up those slugs. I’m have the shims already. Just not sure if I want to get my sheave machined. I’m ok with losing top end I just want more grunt
 
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