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I glad to see/read others doing detailed work and posting good accurate info with small increment changes to these systems. And then learning with a .25 mm shim change a limit has been reached in the system to another area.
As for the seal hump, Arnie use to remove this years ago. I have lost track of this part of his work over time.
I think he learned removing the seal hump allowed too much shim for too much belt rub for 700's.
I was hoping you raised the ratio over 3.25 on the 700 the posted a video of how the belt positioned for the belt cover.
 

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Discussion Starter #102
I glad to see/read others doing detailed work and posting good accurate info with small increment changes to these systems. And then learning with a .25 mm shim change a limit has been reached in the system to another area.
As for the seal hump, Arnie use to remove this years ago. I have lost track of this part of his work over time.
I think he learned removing the seal hump allowed too much shim for too much belt rub for 700's.
I was hoping you raised the ratio over 3.25 on the 700 the posted a video of how the belt positioned for the belt cover.
Adding he 1/2mm shim raised my belt another 1/64" to 7/64" over the top of the secondary. It was 3/16" before adding the 1/2mm shim. I didnt even think about taking pics let alone a video of it but I may before I am done doing normal maintenance. I do have pics of the 3.12 to 1 before I added the shim. I will upload those to the PC and post tomorrow.
 
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Those will help others see what to expect following your work and mod list.
You may want to change your signature to reflect what your riding set-up ratio is, and how you got there. And list who did your machine work.
 

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Discussion Starter #104 (Edited)
Those will help others see what to expect following your work and mod list.
You may want to change your signature to reflect what your riding set-up ratio is, and how you got there. And list who did your machine work.
If you look at post #28 & #55 I did my own machining. I started with a 2mm cut and then recut it to 3mm. the 2mm ended up like 2.74 to 1 and the 3mm got me to 3.07 to 1 ratio. After 1200 miles it was up to 3.12 to 1. Then added the 1/2mm shim to get me to 3.25 to 1.
 

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I quickly looked at your signature for the machining source.
I was looking as your starting ratio results compare closely to Arnie's, did you change the face angle so the effect of machining reduces with rising ground speed?
 

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Discussion Starter #106
I quickly looked at your signature for the machining source.
I was looking as your starting ratio results compare closely to Arnie's, did you change the face angle so the effect of machining reduces with rising ground speed?
Yes, My current cut is a 3mm taper cut. I took off 3mm at the seal hump (Which I also reduced the diameter) and zero at the top of the sheave.
 

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Discussion Starter #107 (Edited)
I said I would update this thread if I changed anything. Well I changed things. I put on new tires that turned out to be 1.5" taller in diameter (25.66" stock tires VS 27.14" Pitbulls) and a total of 66lbs heavier for the 4 tires VS the stock tires. I test road it for 50 miles with the new tires in all kinda of terrain and I could tell the snappiest was gone and it seemed to struggle in deep sand like I had to much clutch weight in it. It also seemed like the belt was slipping from a standing stop. So I decided on trying the EPI Gold spring again. After a few laps around the yard to warm everything up I pulled up to my favorite drag strip spot in the yard, rolled to a stop and nailed it. The front end tried to lift before the tires started to spin but its back to where it was before the tire swap for sure. Running around our little track at our house it would spin the tires any place I wanted to and it does it pretty easily. I have one other thing I might try but not before testing it in the woods again.
 

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Did the top speed change?
 

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Discussion Starter #109

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Discussion Starter #110 (Edited)
This a is a copy and paste from my tire thread and it should be in here as well.


I said...
What I found being I have wet slugs installed is the wet slugs act like a heavier clutch weights to begin with and then toss in a little taller and heavier tires and the purple spring seemed like it was struggling to keep the belt from slipping at a low rpm/mph and could not keep the Rpm's up in loose sand without using a lot more throttle. The Gold spring brought it back to life with the wet slugs.

Ridgway81432 Said....
My thinking on the slugs is.....the extra weight locks the shoe(s) to the drum more firmly, it has to do with kinetic energy, and at a slightly lower engine r.p.m.
Then the heavier secondary spring which is the key part in why the Yamaha c.v.t. works so smoothly and securely raises the amount of resistance to the weights against the cam plate in the primary, which retards the up-shift rate as compared to the purple spring, so more engine r.p.m.s are required thus allowing the engine to produce more torque which is multiplied by the mods you have to raise the pulley ratio.
 

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Discussion Starter #111 (Edited)
I agree the wet slugs make the wet clutch lock sooner. Actually to soon. All you have to do it touch the throttle and its moving. I really dont think it slipping at all unless its under 2000Rpm. I know I have to let the bike warm up before you can even put it in gear or it will jump and take off even at a idle. 36g of wet slug is to much IMO now that I have tried it. 16-20 grams might be prefect?? I really dont know. As far as I know I am the first to make them and weigh them at home. It might be better with some stiffer springs but whats the point of doing that really.

I did noticed right off the get go I lost Rpm's and performance with the wet slugs so I would say the 36g of slug is affecting the clutching just like having heavier rollers. If you look at post #9 & #22 the addition of wet slugs slowed the bike down. Then I added a purple spring and gained back the performance.
 

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Absolutely impressive the level of knowledge you have. I had played in the clutch of my old 500 Polaris several years ago but I was very far from your perfection.
Bravo for all his research and thank you for sharing them ;-)
 

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I agree the wet slugs make the wet clutch lock sooner. Actually to soon. All you have to do it touch the throttle and its moving. I really dont think it slipping at all unless its under 2000Rpm. I know I have to let the bike warm up before you can even put it in gear or it will jump and take off even at a idle. 36g of wet slug is to much IMO now that I have tried it. 16-20 grams might be prefect?? I really dont know. As far as I know I am the first to make them and weigh them at home. It might be better with some stiffer springs but whats the point of doing that really.

I did noticed right off the get go I lost Rpm's and performance with the wet slugs so I would say the 36g of slug is affecting the clutching just like having heavier rollers. If you look at post #9 & #22 the addition of wet slugs slowed the bike down. Then I added a purple spring and gained back the performance.
By lowering the stall point the slugs reduce torque converter effect that slipping wet clutch has been designed for.
Heavier weights cause an earlier shift out.
 
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Discussion Starter #114
By lowering the stall point the slugs reduce torque converter effect that slipping wet clutch has been designed for.
Heavier weights cause an earlier shift out.
I agree with that. At my next oil change I might make a change on the wet slugs. For the most part I like them but i dont like just touching the throttle and it moves. In really tight woods it makes it kinda tough at times.
 

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I agree with that. At my next oil change I might make a change on the wet slugs. For the most part I like them but i dont like just touching the throttle and it moves. In really tight woods it makes it kinda tough at times.
That does sound like very aggressive initial engagement
 

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Discussion Starter #116
That does sound like very aggressive initial engagement
Its just a little to agressive. I might try like half the weight if I make the change. It's 36g now so maybe 18 to 20g.
 

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Its just a little to agressive. I might try like half the weight if I make the change. It's 36g now so maybe 18 to 20g.
Super interesting stuff.

@reogem, I like your comparison to a torque converter.
 

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Discussion Starter #118
Super interesting stuff.

@reogem, I like your comparison to a torque converter.
Agreed. Its interesting and if you really want to find out what does what the best way to learn is to dive in. lol. I dont mind working on my Grizzly at all for the most part. I also like to tinker on things as I am a gear head to begin with so while doing clutching changes its a learning process as well.
 

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Well it looks like for the most part that our rainy spring is about to end so its time to get ready for some clutch tuning. I bought one of those little tachometers for testing purpose only and put it to use after I mounted it. My bike is a 2017 708cc Grizzly all stock (Except EHS Fuel Controller) including the tires & belt. It has 40.4 hours on it and 540 miles. The tire PSI was set at 7PSI and the air temp was between 55*- 60*. This is a average of 2 to 3 test for Rpm's on a dry paved road. FYI, Once warm the idle settles in right at 1600 - 1610 Rpm's.

10 MPH = 3250 - 3280 Rpm's
15 MPH = 3760 - 3800 Rpm's
20 MPH = 4150 - 4180 Rpm's
25 MPH = 4410 - 4440 Rpm's
30 MPH = 4730 - 4750 Rpm's
35 MPH = 5050 - 5080 Rpm's
40 MPH = 5380 - 5410 Rpm's
45 MPH = 5650 - 5680 Rpm's
50 MPH = 6010 - 6040 Rpm's
55 MPH = 6240 - 6280 Rpm's

That is all I had time for tonight but will try to get the 60 & 65MPH - Rpm's before the rain moves back in tomorrow for a day or so. In the Pic. When I first started the Griz the tach was set on the wrong setting so it only read 1/2 the Rpm's it was supposed to.
If you are interested, I have one new sheave modified with my Coop Mod#3 left!
25% lower takeoff ratio with no top speed loss at all?
 

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If you are interested, I have one new sheave modified with my Coop Mod#3 left!
25% lower takeoff ratio with no top speed loss at all?
He machined his own sheave to achieve 3.1:1 specs already.
 
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