Yamaha Grizzly ATV Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
So... after trying to work the math with tires and cvt mods for my machine, 2019 Grizz 700 SE with 27x10x14 zillas. What has Yamaha considered stock at this point and has Yamaha taken the tires into consideration at all or is the cvt set stock as with a typical 2019 grizz 700 with stock 26x 8 or 10 x 12 tires? Should I be basing my changes on stock 26" or stock 27" tires? I know maybe knittpicking for some and not even close for others, but just want to find where I am at going forward. Thanks to any who want to chime in.

Grip

PS where does the 6% gear reduction Yamaha specified take place and was that platform wide for the 2019 686?
 

·
Premium Member
Joined
·
10,355 Posts
:)
Here we gooooo. :)
I think Yamaha engineers one system set-up for the year model and uses the same set-up for several year models in a row. And this set-up is for the base (cheapest priced) model available for the year. I have read post on the 6% thing but not enough information to know it is important, or even real. I don't go with 'my buddy said' or 'the guy at the dealership said', I look for repeatable facts. As an example, that's why I use and recommend COOP45 only for machining and didn't go with J.B.S. Years ago we had a member in Canada that learned COOP's work and he did do a good job, but is gone now.
I would use the actual smaller stock tire diameter (roll-out for circumference) for a base line, and the stock pulley ratio too, to build ratios with.
Just my way of thinking......
 

·
Registered
Joined
·
1,955 Posts
I own one of these 2019 Grizzly SE and I can tell you for sure there is no difference in cluching between this model or the regular EPS Grizzly. Stock weights in both are 18 gram. Yes 6% gear reduction began in 2019.

These 27 zillas of the SE actually only measure 26" tall and the normal EPS 26" Maxxis tires are closer to 25" tall.
 

·
Premium Member
Joined
·
10,355 Posts
Now that we have a report, here's my question.....
Based upon members writing they add shim, machining, a narrow belt or reduced diameter weights, alone or in any combination, to raise the pulley ratio, what does this have to do with gear ratio discussion, or a clutch of any kind?
This is similar to a chain drive dirt bike, we change the sprocket size(s) for different sprocket ratios, which has nothing to do with gearing in the transmission.
I think pulley(s), sprocket(s) and gear(s) are friction items used to transfer power, and due to their location and ability to be replaced or altered is most important for proper terminology.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #5
Ok then since the zillas are 1" taller thats 4% loss, anyone know the stock 26" tire weights? I got 42# for the mounted zilla. How do you equate the weight differance? Or just work it back from published wet weight?
 

·
Registered
Joined
·
1,955 Posts
Your SE zillas 27x10 on 14" custom wheels way "around" 35 lbs a piecish...
 

·
Premium Member
Joined
·
10,355 Posts
Ok then since the zillas are 1" taller thats 4% loss, anyone know the stock 26" tire weights? I got 42# for the mounted zilla. How do you equate the weight differance? Or just work it back from published wet weight?
This is what I was getting at as an example, nothing personal intended....I am going to use your post as an example here.
You have to do the roll-out to know the exact circumference at the p.s.i. you like, then you can calculate the exact true tire diameter.
Then you ask a 4% loss, loss of what?
I suggest forgetting about the tire weight, but do what you want. I can load 100#s on the rack and not cause a big slowing in forward bite. And if you could find narrow tires the same weight as the stock tires, 3" taller, you would understand its the added circumference causing the problem, not the weight to a detectable degree.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #8
This is what I was getting at as an example, nothing personal intended....I am going to use your post as an example here.
You have to do the roll-out to know the exact circumference at the p.s.i. you like, then you can calculate the exact true tire diameter.
Then you ask a 4% loss, loss of what?
I suggest forgetting about the tire weight, but do what you want. I can load 100#s on the rack and not cause a big slowing in forward bite. And if you could find narrow tires the same weight as the stock tires, 3" taller, you would understand its the added circumference causing the problem, not the weight to a detectable degree.
No I get that, just trying to get all variables accounted for that is all. My 4% loss was a loss of performance against the engineered stock to account for tire height difference. My Tires weight roughly 42# per my scale (could be off) rollout was 82" @ 4.5psi. Being I do not know the 26" stock tire weight and rollout I asked. I am really just interested in finding roughly the percentage of increase over stock with my current setup. I really do not need to know just curious as I do not race or ride extreme in nature. I do not intent to change secondary spring as I am not experiencing any slipping and do not need the rpms to increase. I would not mind the extra .5mm shim but need more seat time for that, If it performs I am good if not I just want to find out what I would go after. As I sit now with only a machined sheave I believe I have about a 10% gain in performance over stock in general terms. I will have to weight the tire again as I do believe it may be lighter that 42#. I appreciate you guys helping me out, I have learned a lot about the cvt adjustments through the sticky and other discussions on this forum, it is obvious a few of you have been there and done that, me somewhat new being I spend most of my riding on geared machines.

Grip
 

·
Premium Member
Joined
·
10,355 Posts
:)
Now we have something to work with.
Your current set-up includes tires that are so close to 26"s true, that is a good number.
Now you need someone with a stock base Griz to measure their stock tire roll-out and post that number, you didn't know to measure your stock tires before starting c.v.t. mods.
And you would like someone to post their stock '19' 700 c.v.t. pulley ratio as a base line to know the differences you added.

I was lucky when I started c.v.t. mods, there was limited info so I started slow with shim, and a purple spring and a new belt, all these bought before I took the cover off the first time. I was lucky because I could go back to stock for the starting numbers I need, but did not know to get before I started the project. Also remember I started these mods after adding taller tires that caused the problem, but I had a buddy on a stock 660 so could measure his bike to know the stock roll-out. for you to get this number now, go to a dealer and measure a stock Griz there.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #10
Yep, I never had the chance because my model came stock with the 27" zillas, that is the problem I am trying to decipher. So the standard eps has the stock 26x8or10x12, Vincent (thank you) says they measure in at roughly 25" diameter, 1" difference. But if anyone would like to share that information for certain with weights would be helpful. I did check my stock ratio, came in at 2.5:1 after sheave alone I am at 2.75:1.
 

·
Registered
Joined
·
320 Posts
As an example, that's why I use and recommend COOP45 only for machining and didn't go with J.B.S. Years ago we had a member in Canada that learned COOP's work and he did do a good job, but is gone now.
Are you referring to BF Clutching? If so, he's not really gone, just not really into dealing with public scrutiny. He did my work. I'm very good friends with Brian. Really nice haveing a cvt Guru 10 min away.

Sent from my Pixel 2 XL using Tapatalk
 

·
Premium Member
Joined
·
10,355 Posts
Not BF Clutching as far as I know, unless BF used another screen name here years ago.
I think you know a different guy.
The reason the guy I knew started doing machining like COOP was the problems/expense o border customs going north. He had the place and stuff to do the work, I don't remember the details but he got with COOP for pointers to do work up there for less cost to the customer and I know after a while the orders slowed to a crawl.
I haven't heard from him in years.
 

·
Registered
Joined
·
320 Posts
Oh ok. Very possible. There are a few guys that mastered the cvt from sleds and started doing ATVs when they got more popular.

Sent from my Pixel 2 XL using Tapatalk
 

·
Premium Member
Joined
·
10,355 Posts
Yep....
Pulley systems are very handy and flexible, the mods done (in my opinion) depend on;
1) the type of power plant driving the front pulley,
2) the brand, thus the patent style of the pulley system.
 
1 - 14 of 14 Posts
Top