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Discussion Starter #1
Hey guys I would like to increase my bottom end a little without spending alot of money. Can i just add a shim in my primary without adding a different spring or weights?? Basically just put a shim in thats all?? Like a 1.5mm shim or 1mm? Any help would be appreciated thanks.
 

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Yes you can do the shim mod without changing the spring. I ran mine with a 1.5 mm shim for 750 miles before I upgrade my spring to an EPI orange.
You do run the risk of having some belt slip without upgrading your spring , but I guess I lucked out cause I never noticed any.
 
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Absolutely! You can add 1.5 mm to give you the most low end in the shim department. You do not have to change anything else. I run 2mm shim but I have a 660 and can run more shim then a 700. I think I never got the full force of the shim because on reassembly I let my weights fall out without realizing it. Oops.
Hey @Vincent, yes belt slip is possible and I experienced it under load. Like in 4x4 trying to get over a large drift. Which is why I bought a EPI purple spring. Yet to be installed. Grizz be in limp mode.
 
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You ran 2mm in your 17... Hmm. Maybe with the newer ones you can do 2mm. This is the first I have heard of it. Older 700s can only have 1.5mm without starting to worry about rubbing. This is what I have read, so if anyone has 2015 or older Grizzly 700 running more then 1.5 could they post up here. It will be useful for O.P.er and I am curious.
 
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2016 grizzly 700se with 1.5mm shim I have rubbing on the cover. It’s minor and it’s now worn all it’s going to so I stopped worrying about it.
Ratio 2.8:1 approx.
ran 2.9:1 ratio with machined sheave and 1mm shim.
I got a bit more Rub but noting serious.



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Belt sticks out quite far out of the secondary with the sheave and 1mm shim.



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Let me add this for earlier years 700 owners;
With the shim mod, 1.7 mm's was the comfortable limit before rubbing, but not belt rubbing.
700's were known to accept 2 mm's but the grease cover screws rubbed inside the cage support when the primary started to turn.
I added 1.5 mm's to a '15' 700 a couple months ago with no rubbing.
 
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Let me add this for earlier years 700 owners;
With the shim mod, 1.7 mm's was the comfortable limit before rubbing, but not belt rubbing.
700's were known to accept 2 mm's but the grease cover screws rubbed inside the cage support when the primary started to turn.
I added 1.5 mm's to a '15' 700 a couple months ago with no rubbing.
Exactly.
In many cases, guys were grinding away a little material from the cage so they could install 2.0mm of shim. Some even went as far as 2.2mm, but splines issues and belt rubbing issues were the limiting factor at that.
 
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shoot, guess im lucky or blind! no rubbing when i had 2mm shim or w/ current sheave(3:1 ratio).
 

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I ran 1.7mm in my 2010 700 with no issue. I didn’t try to go any further but think I would have had to do a little grinding on the cage if I had. I still had room on the splines.
 

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One more tidbit of info ... If you run greaseless there’ll be no cover screws to hit the cage. That’s one issue you wouldn’t have to worry about.



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[MENTION=36929]@ridgeway81432, I think the answer to this is buried somewhere in the forum, but maybe you would be so kind as to repeat it for me. On my 2008 700, stock engine, 26" Kenda radials on 12" wheels. The more I ride it since the new tire/wheel combo, I can tell a difference in the low end power, which was to be expected. It is not a big difference, and it's not enough to cause any wear problems with the wet clutch. But..my woods trails are rough, twisty, rocky and snowy or icy in the winter. Low gear is a little too low, and high gear is a little too high. I have a 1mm shim and a .5mm shim, and a purple EPI spring none of which have been installed yet. I know that I will lose 4 to 5 MPH off my top speed, but I have never hit the limiter on it anyway, and usually the fastest I would run for a short period of time is 50 mph, so that is not really a concern for me. I don't mud, I don't care about wheelies. I want good smooth acceleration, good backshift. I know about the Coop45 mod 3, and that might be in the future. It's not really about the money, it's more about the down time, and it seems to me that for what I do with my Grizz the shim and spring is likely all I need. Do you think I need both shims, or just the 1mm?
I have read a confusing amount of stuff about the weights. In your experience, should I change the weights while I am in there for any reason, if so which weight should I get, or am I good to go? Very much appreciate you'r expertise, or anyone else's for that matter.
 

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[MENTION=36929]@ridgeway81432, I think the answer to this is buried somewhere in the forum, but maybe you would be so kind as to repeat it for me. On my 2008 700, stock engine, 26" Kenda radials on 12" wheels. The more I ride it since the new tire/wheel combo, I can tell a difference in the low end power, which was to be expected. It is not a big difference, and it's not enough to cause any wear problems with the wet clutch. But..my woods trails are rough, twisty, rocky and snowy or icy in the winter. Low gear is a little too low, and high gear is a little too high. I have a 1mm shim and a .5mm shim, and a purple EPI spring none of which have been installed yet. I know that I will lose 4 to 5 MPH off my top speed, but I have never hit the limiter on it anyway, and usually the fastest I would run for a short period of time is 50 mph, so that is not really a concern for me. I don't mud, I don't care about wheelies. I want good smooth acceleration, good backshift. I know about the Coop45 mod 3, and that might be in the future. It's not really about the money, it's more about the down time, and it seems to me that for what I do with my Grizz the shim and spring is likely all I need. Do you think I need both shims, or just the 1mm?
I have read a confusing amount of stuff about the weights. In your experience, should I change the weights while I am in there for any reason, if so which weight should I get, or am I good to go? Very much appreciate you'r expertise, or anyone else's for that matter.
Don't change your weights! If you want to keep it quick and simple just pop in a 1 or 1.5 mm shim and see how you feel about it. It will only take a few hours and you'll notice your bike will perform like it did with small tires.
 

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Don't change your weights! If you want to keep it quick and simple just pop in a 1 or 1.5 mm shim and see how you feel about it. It will only take a few hours and you'll notice your bike will perform like it did with small tires.
@Vincent, I was kinda thinking that was the answer, but wanting to be sure while I have it apart. Thanks!!
 

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[MENTION=36929]@ridgeway81432, I think the answer to this is buried somewhere in the forum, but maybe you would be so kind as to repeat it for me. On my 2008 700, stock engine, 26" Kenda radials on 12" wheels. The more I ride it since the new tire/wheel combo, I can tell a difference in the low end power, which was to be expected. It is not a big difference, and it's not enough to cause any wear problems with the wet clutch. But..my woods trails are rough, twisty, rocky and snowy or icy in the winter. Low gear is a little too low, and high gear is a little too high. I have a 1mm shim and a .5mm shim, and a purple EPI spring none of which have been installed yet. I know that I will lose 4 to 5 MPH off my top speed, but I have never hit the limiter on it anyway, and usually the fastest I would run for a short period of time is 50 mph, so that is not really a concern for me. I don't mud, I don't care about wheelies. I want good smooth acceleration, good backshift. I know about the Coop45 mod 3, and that might be in the future. It's not really about the money, it's more about the down time, and it seems to me that for what I do with my Grizz the shim and spring is likely all I need. Do you think I need both shims, or just the 1mm?
I have read a confusing amount of stuff about the weights. In your experience, should I change the weights while I am in there for any reason, if so which weight should I get, or am I good to go? Very much appreciate you'r expertise, or anyone else's for that matter.
There are previous threads and posts to help with your question, but recently old threads became very hard to find.
So, here are a few things you NEED to know to help you determine why you are experiencing a difference in low end pull.
The 2008 700's had stock tires with a 23.5" roll-out as engineered, and the drag from these tires determined the stock C.V.T. set-up for average riders.
You now have 26" tires with a different roll-out, and if the new roll-out is like the O.G.'s I run, your tires are 26.5" true diameter, not the 26"s stated. To know the actual diameter, measure your new roll-out.
When I added new, taller, tires I experienced a 3" difference in diameter, or an 11" difference in roll-out, and that is THE cause for the weaker low end performance. Yes there is a weight increase, but that has much less to do with the problem, and the solution.
It took me 2 years and many dozen different C.V.T. combinations to understand the Yamaha C.V.T. system, so here is what many need to know to get started. I have hands on experience with 2015 and older 700's, 660's and 2012 550's, so those with newer rides be careful. The theory for newer machines is the same, but the starting numbers may be different, and so the results can be different too.

The 2008 700's had a 2.5:1 pulley ratio, but with wear over time the current ratio can be slightly higher. I'll use the 2.5 to 1 for now.
By adding 26.5" tall tires, I bogged the drive system down 11%, so over time learned that by raising the pulley ratio by 11%, I got the stock haul ass feel back with the taller tires. (if your 26" tires are actually 26"s, then you bogged your system down less than 11%, but not much)

The label roll-out is a term I started using instead of circumference, and this measurement can be used to determine the exact diameter, or height, of a tire at whatever p.s.i. you like to ride.
I use this link to calculate the actual diameter;
http://www.csgnetwork.com/circle_sphere_area_calculator.html

If you had a stock 2.5 ratio, then I suggest you raise the ratio 11% to 2.775 to 1 to get your feel good back. I run a 3.5 to 1 ratio for more haul ass than stock with the taller tires listed in the sig.
I suggest adding the 1.5 mm's of shim you have now, after measuring your stock ratio, to determine the increase in your pulley ratio. Measure your new roll-out to calculate what you need to raise your pulley ratio to, then see what you get with the shim.

As for the spring, that added squish to the belt to prevent belt slip. The stock Yamaha 700 C.V.T. system has the equivalent to the E.P.I. orange spring for the 2.5 to 1 ratio transferring torque to the transmission. The shim magnifies the torque transferred, so the belt can slip under heavy throttle, so you can ride to see if you get slip, or add the spring at the time you add the shim. I like the additional back-shift rate of the purple spring, but you may not and have to experiment with springs some.

Here's the deal with changing weights.
The weights react to rotational force, so lighter weights require more engine r.p.m. before moving toward the outer edge of the primary pulley. This movement is called up-shift, and the rate of up-shift can be managed, and also requires additional torque for heavier weights to keep the grizz in the sweet spot for optimum forward bite.
We multiply the torque to overcome drag from tall tires, then continue to add/multiply torque, and I do this to use heavier weights for increased forward bite. I do this for 2 reasons, 1) to lower cruising .r.p.m.'s for increased m.p.g., or 2) for quicker acceleration to high speed.

I do not suggest heavier weights for most, and do not see reason for lighter weights.

As for belt rubbing, the 660 has more room in the cover than the 700's, but some with 700's have allowed some partial rubbing in the cover to get to higher ratios. I have a lot of rubbing, but going slow with ratio increases I slowly got the cover material out. Yes my cover is thinner, but it doesn't take much to keep the water out and the rubbing is in a location protected from rocks or sticks.

As you mentioned top speed, yes the shim mod lowers the top speed but that can be reversed, by cutting the cam plate.

I hope this helps you.
 

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Just to share some info.

In my case with my old 25.5" diameter tires I'd hit 62 mph on gps. My initial CVT ratio was 2.9:1 with my machine sheave.

Now I'm running 26.5" diameter tires witch is 4% larger diameter. I'm planning on adding a 0.5mm shim to my sheave, I'll go from 2.9 to 3:1 initial ratio witch is a 4% lower gearing threw out my cvt 's range. So basically putting me right back where I was before switching tires.

I honestly don't need to mess around with my cvt at all, it performs very well as is, but I enjoy working and tweaking my machine and simply can't stop myself from experimenting.

Also like Ridgeway mentioned the weight of your tires doesn't have as much impact on all this as you mite think. I had a hard time believe this myself, but after adding 25+ lbs of rotating mass on my bike, I now completely agree with him.
 

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@Ridgeway81432, that is a perfect summary of what I had seen all over the place, so much easier to put into practice. Thanks very, very much.
 
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@Vincent, thanks for that info. I didn't think the weight change had much to do with it for the simple reason that the bike has plenty of grunt under normal trail riding conditions with the new tires even with a heavy passenger. But trying to crawl around out back in the woods with the bigger tires, I pretty much have to use low gear. The info that you and ridgeway have summarized lets me know that the 1.5 shim will do what I want torque wise, and I like/need good backshift, plus I do haul some weight at times, so the purple spring will give me the backshift I need plus ensure that the belt doesn't slip under a good load. Thanks!
 

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In my case with my old 25.5" diameter tires I'd hit 62 mph on gps.
Also like Ridgeway mentioned the weight of your tires doesn't have as much impact on all this as you mite think. I had a hard time believe this myself, but after adding 25+ lbs of rotating mass on my bike, I now completely agree with him.
Vincent brings up a good point, to measure speed by G.P.S.
Older machines on stock tires measuring 23.5"s true caused the bike odo to read 26 m.p.h. when the grizz was doing 20 mph by G.P.S.
Then with 25" true tires, the grizz odo read 23 m.p.h. when actually going 20 m.p.h. by G.P.S.
It is with tires measuring 26.5"s true that the bike odo and G.P.S. read the same.
One day I rode with 2 other members, on these different tires sized and learned what was what.

As for the weight of the tires/wheels causing drag reducing acceleration by increasing unsprung weight, this is what I determined after riding with another stock '06' 660. At the end of the day's ride, his machine indicated we had gone 82 miles when my machine indicated 61 miles traveled. Yes we had minor variations in the exact paths traveled that day, and I did make a few more loops into the creek, but the differences traveled were no where close to 21 miles...hum.
The next day the three machines spoken of above were to go out again, and when fueling up for the day another piece of the puzzle was revealed. The stock 660 took a lot more gas then mine after basically the same day ride....hum.
Later on after the others returned home, I did some calculations and bingo, discovered a problem others hadn't written about.
The stock grizz on tires with a 74" roll-out turned the tires 856 times to cover a measured mile.
My grizzly on tires with a 83" roll-out turned the tires 763 times to cover a measured mile.
The extra distance traveled per turn of the taller tire covered more distance, burning less gas when cruising at same true ground speed of the grizz with the shorter tires.
I weigh more than the other rider, and used heavier tires and carried the beer.
I've written this in other threads, but throw this out for others to consider;
These were two '06' 660's with no motor mods using stock carburetors and exhaust systems. The machines were very near the same weight with riders and supplies, but one burned almost twice as much gas as the other, why?
I'm guessing the other machine worked, turned the engine enough, to cover the extra distance indicated, wasting gas unnecessarily.
I think the ratio of engine revolutions to turns of the rear tire was different.

Modifying the Yamaha C.V.T. system can free up the power produced by the stock engine.
For those planning mods to their grizzly;
1) Measure the tire roll-out of the stock tires, to compare to the tires replacing the stockers.
2) If modifying the C.V.T., determine YOUR machine's pulley ration before removing the primary for the first mod.
These numbers help others help you determine a good set-up and the parts required.
There is no one size fits all set of mods, for those posting threads of 'I need help getting power'. These things all put out the same power (or close enough to make that general statement.), so what most here on G.C. are actually doing is changing how the stock power is applied.
As an example to get our best help;
For those that have changed tires, you need to tell us the actual change, and that is done best by telling us the roll-out.
If you have added shim, tell us the stock and modifies ratios.
Let me get off the soap box for now:)
 
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