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Discussion Starter #1
Been doing tons of reading and learning all about how the Grizz cvt works and how to alter it. A few things still seem a bit confusing. What are "slugs" for and what possible benefit do they provide?? And also what is the pupose of "500" and "1000" wet clutch springs?

Just curious on the pros and cons of these items and what they do.
 

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Discussion Starter #3
If I'm not mistaken 500 & 1000 are what rpm the wet clutch starts to engage at...
That makes sense but it idles at 1,550-1,650 rpms. Unless its geared down from the crank???
 

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Generally speaking, 500 stall springs engage 500 rmps above the factory springs and 1000 spring 1000 rpms higher.
The engine has to turn faster to create the centrifugal force needed to over come the spring rate forcing the shoes out to engage.
Adding shim or a machined primary multiplies the torque and stall springs don't.
Stall springs produce a like effect as dumping the clutch at higher engine rpm.
 
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Yes, stall springs simply raise the RPM where the clutch engages by 500 or 1000 RPM higher that stock, approximately.

Slugs do the opposite. They increase the weight of you wet clutch springs so the clutch engages at a lower RPM. The increased weight produces more centrifugal force to over ride the spring pressure at lower RPM.
 
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Slugs are debatable, I see no point to them on the average atv. We had a cvt set up in our group that was exactly like my bike except he had slugs in his. No matter who rode them they could never see a difference. Only difference is that his wet clutch burnt up early and mine was fine. I would never put them in a machine as I have not seen a possitive to them personally

Rather then slugs I have found you need to drive the machine mental through the wet clutch. Drive it so it engages not burns know when to be heavy on the Gas. Trying to crawl over things super slow is just asking for it. Get on the gas and get that clutch engaged
 

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Discussion Starter #7
Thanks all for the info!!! Love this forum!! Such a source of info and help that comes from experience not just hearsay!!!

So the stronger the wc spring, the more it will resist centrifugal forces and engage even higher rpms. I don't think stronger springs will benefit me at all. Slugs on the other hand sound like a good idea but in practice are useless or even harmful to the wc.

The trails I ride in western mass are very tight and quite rocky at times. I do end up using low range often because Like Trev mentioned To avoid burning the wc I have to keep nailing the throttle to overcome takeoff forces over large rocks. It seems like high range starts off being geared too tall and it seems to b tough on the wc.

Before winter hits, i plan on finally getting new tires(Bearclaw htr) in the 26" size and plan on sending out primary sheave for machining and possibly some shims and purple spring.
 

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I may not agree with you on the tires, but the machining/shim/spring mods. are right on tract.

Raising the pulley ratio magnifies the engine torque produced at any engine r.p.m. At low speed like when you crawl over rock, with low torque output, the wet clutch engages fine, but in the stock configuration most have to add throttle and makes/causes more stress on the wet clutch unit which is a friction unit.
Then when taller tires are added the problem is compounded.

As you stated, 'like being geared to tall', that is what raising the pulley ratio counteracts.

Shims are good but have a limit of how much can be installed.
The machining provides the same result, but more of it, and some machinists have figured out how to change the angle of the stock sheave belt face so top speed isn't reduced before the shim is combined with the machining. The top speed loss from the shim can be counteracted with a cut cam plate later if you want.

This video was taken by another member, rio, last spring. I had backed my grizz over a drop and landed in the bottom of the creek. After throwing the grizz on its side, other members replaced the bent a-arm so the grizz could be ridden out.
The value of this video is watching/listening to the engine as the grizz moves up the rock coming out of the creek. Its not me on the grizz, but another member as I'm the guy on the crutches.
Anyway, watch and listen to the motor. The grizz was in 4x4 lock, with a very high ratio and the engine didn't need to work hard. The engine is stock, so multiplying the torque was the difference.

 
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if you were to put the wet clutch springs in as well as slugs it would be counter active.
the wet clutch springs would be used with bigger tires and if you want a more aggressive take off. If you are crawling at slow speeds not a good idea
The wet clutch slugs are for modified engines that want to have more clamping force for the wet clutch( less slippage) the slugs will not damage wet clutch, they help it, less slippage means less heat etc. Slugs will or should actually let engine engage wet clutch at a lower RPM due to the fact the the extra mass in the movable clutch arms will over power the stock springs
Stock bike slugs are not required you go bigger tires and big hp

I couldn't get 150 kms out of wet clutch over last 2 years. This year 600 kms so far no issues
They have been using them in the rhinos for years when they supercharge them. Only way they can make the wet clutch live in those as well Is slugs
 
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Discussion Starter #10
if you were to put the wet clutch springs in as well as slugs it would be counter active.
the wet clutch springs would be used with bigger tires and if you want a more aggressive take off. If you are crawling at slow speeds not a good idea
The wet clutch slugs are for modified engines that want to have more clamping force for the wet clutch( less slippage) the slugs will not damage wet clutch, they help it, less slippage means less heat etc. Slugs will or should actually let engine engage wet clutch at a lower RPM due to the fact the the extra mass in the movable clutch arms will over power the stock springs
Stock bike slugs are not required you go bigger tires and big hp

I couldn't get 150 kms out of wet clutch over last 2 years. This year 600 kms so far no issues
They have been using them in the rhinos for years when they supercharge them. Only way they can make the wet clutch live in those as well Is slugs


So slugs help with the wc's grip. Or at least that's what they r supposed to do. Sounds like they would add life to a wc. Plus a lower rpm engagement would mean less wear and a slower takeoff. Sounds good to me.

Anyone else have good/bad "slug" info??
 

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With slugs, you wont need any more clutch work or your going to jerk in whatever gear your in, unless you have giant heavy tires. If you don't plan on getting a heavy tire, I wouldn't do slugs unless you are an extremely heavy puller, but with light weight tires, just go with what you said with shims and (or) sheave and a spring for your secondary.
 

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I run a carbed grizz, so what if at the lowest rpm the engine would stay running, the wet clutch was engaged? Its all about the total package.
 

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Discussion Starter #13
I run a carbed grizz, so what if at the lowest rpm the engine would stay running, the wet clutch was engaged? Its all about the total package.
Relax man, just thinkin out loud. Lookin for insight and knowledge to better my Grizzly experience.
 

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I'm relaxed, just pointed out another thing to think about.
 

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My unqualified 2.0162¢

Because of the arrangement of the springs and the design of the blocks. The added weight has little effect on the idle movement of the clutch blocks. The fat end of each block is connected to the little end of the block before it. The center of the block is offset on the shafts. When a block starts to move it is applying opposite pressure to the block it is attached to. As the block rotates the effective length of each block arm changes as they rotate around the shaft.
The long arm spring attachment point moves farther and the short arm spring attachment point moves closer to the shaft. The long arm gains mechanical advantage and the short arm loses mechanical advantage. A higher rpms they lock up better with the added weight.
Blah! Blah! Blah!
A drawing sure would help:deal:
 
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