Yamaha Grizzly ATV Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
365 Posts
Discussion Starter · #1 ·
I just wanted to report on my findings on the Performance of this mod package, ( 26” big horn og tires on 12” steel rims, clutch 1.5mm shim, EPI purple spring, EHS air box mod K&N filter, EHS air box lid, EHS fuel controller, 2R tip) With my totally stock grizzly, top speed fluctuated between 67-68 mph. And not very snappy off the line but after it got rolling it was very responsive to the throttle, radiator fan cycled quite often, backfiring on deceleration was hideous! With the mods above, top speed fluctuated between 62-63 mph. I noticed it would stumble a little at 63 mph. I wondered if it was boarding on the rev limiter because of the shim mod? Very snappy off the line and all the way through the power band. Air temperature Today was 60 degrees, did not notice fan cycling, backfiring on deceleration was Virtually nonexistent. This is my nonprofessional findings, hope this may help someone.
 
  • Like
Reactions: jvictory1974

·
Registered
Joined
·
35 Posts
thanks for the report. sounds like your happy with your mods. did you get a feel for what % gain came from the clutch & spring versus the fuel controller & exhaust/intake mods
 
  • Like
Reactions: RDC

·
Registered
Joined
·
191 Posts
I’m curious too. My next mods will be clutch work including spring. I know the shim mod is cheaper. Other than losing top speed ,which I don’t mind at all , I am considering Coops sheave mod. I really wonder if you can tell the difference between the shim mod and the sheave mod other than top speed.
 

·
Registered
Joined
·
365 Posts
Discussion Starter · #4 · (Edited)
thanks for the report. sounds like your happy with your mods. did you get a feel for what % gain came from the clutch & spring versus the fuel controller & exhaust/intake mods
Hi Pedscda, I am pleased with the mod’s I have made. I am not even going to try to guess at a percentage, but I will try to explain the best I can. As for the clutch and spring, it was done for more low end torque, like for bringing your front wheels up to clear obstacles like small fallen trees and what not, maybe pulling something and rolling stronger at slower throttle if you know what I mean. So the torque I gained from stock was noticeably, earth shattering, no. As far as the fuel controller, air box and exhaust tip I wanted the lean condition to go away,let the engine run cooler and breathe and exhale more freely, which it did. I can tell by the throttle response, deceleration backfiring virtually gone and radiator fan does not cycle nearly as often. Do I think it to be worth the money, for me it was. I hope this helped you.
 
  • Like
Reactions: Madkawi750

·
Registered
Joined
·
365 Posts
Discussion Starter · #5 ·
Hi Rick, I am not sure how much torque you are needing but I would do a shim mod first then go from there, can’t comment on the sheaves personality but you would definitely get more torque with coops mod!
 

·
Registered
Joined
·
191 Posts
I would like to know if someone out there did the shim mod first and then at some point did the coop mod. Hell , maybe I will just go this route and report back in the future.
 

·
Registered
Joined
·
1,399 Posts
I would like to know if someone out there did the shim mod first and then at some point did the coop mod. Hell , maybe I will just go this route and report back in the future.


I did the shims, then went with machined sheave in 2016 grizzly 700.
I was kinda disappointed.
My belt ratio with sheave and 0.5mm shim is barely lower than with 1.5mm of shims with stock sheave.
I was hoping for the 3:1 ratio I got from the machined sheave in my 2009 700.
Same brand and everything. I can’t make sense of it.
I’m rubbing the cover belt so I can’t get any more ratio or I’d rub a hole through.

With the 2009 and a machine sheave I had a tiny bit of cover rub, same as I do now,,,, but I had 3:1 Ratio. I’m at 2.8:1 with the 2016 grizzly.

What I DID gain was way more speed in low range before rev limiter.
I hit 69km/h (41.5 mph) in low and I cannot hit the rev in high range. With just shims I would rev limit at 35mph low and 60mph high range.

I would trade the top speed for more low end. 3.5:1 would suit me... heck if even go 4:1 if it wasn’t a pipe dream.
I love low speed control when towing my firewood trailer.

I had hoped for more low end.

The yammy engineers did something to the 2016+ grizzlys.... they don’t have the low speed control the older grizzlys have. I’m thinking it’s transmission gears.


Sent from my iPhone using Tapatalk Pro
 
  • Like
Reactions: RDC

·
Premium Member
Joined
·
824 Posts
rick- FYI on the Coop mod. After Arnie (Coop45) gets done with the mod sheave it will get you close to 2.5mm of comparable shim. You do not lose any top end and gain on low end. My original ratio count was around 2.55 to 1. After installing the Coops the count went to 2.9 to 1. Then I threw in .7mm of shim and got 3.1 to one. Coop warns you though that anything over .5mm of shim may/will cause belt rub on the outer primary case. He was right, I had rub, but just kept taking it off and sanding it down. Most of the rub was at the bottom of the case. But no problem with it now. Very seldom do I have to ride in low gear and when I do it's a stump puller. This was done on a 2013 700 Grizz.
 
  • Like
Reactions: RDC
1 - 8 of 8 Posts
Top