primary weight grind on M8

[summ8rmk]

I took my 09 M8 to a perfomance shop and had the primary weights "grinded" to make the clutch engage like a skidoo or polaris and I am very satisfied. There is no more slamming on engagement my sled takes off so smooth its much better in the trees! anyone else do this mod? I recomend this mod to every M8 owner.

 

[thumper450]

$$

where did they pull it from? Did you take down 68gram weights?

 

[summ8rmk]

stock 75 gram weights. the grind isnt to remove weight necessarily but just enough to make a real smooth engagement thats all i know. but man is it smooth on take off, just like my summit and rmk. I always hated the harsh slamming on engagement. I am now happy!

 

[mtn mike on boost]

stock 75 gram weights. the grind isnt to remove weight necessarily but just enough to make a real smooth engagement thats all i know. but man is it smooth on take off, just like my summit and rmk. I always hated the harsh slamming on engagement. I am now happy!

75 gr.? wow, we are the same elevation and i just ground some 68"s to 67"s.
tell me this sled isnt stock or near stock?????

 

[Mr. BB]

Last year about 7 of us around Yakima were running this mod and it works great, especially if you have an engagement of around 4000 rpm or higher. The AC gold does a fairly decent job of calming down the engagement, but not near as well as the weight mod. The mod consists of grinding a 1/2" flat spot centered under the roller. Only 1/4" is used by the roller as it transitions up on to the shiftout ramp. For some reason this works really well. At least another 7 or 8 guys have tried it this year and love it. It worked really well on 1 team secondary that I know of. In Yakima Jon at Jon's Golf and Ski has been doing this mod. If this is something that really annoys you this mod will put a smile on your face.

 

[summ8rmk]

yup jon at jons golf and ski on fruitvale in yakima. he knows how to make a cat run good.

 

[summ8rmk]

75 gr.? wow, we are the same elevation and i just ground some 68"s to 67"s.
tell me this sled isnt stock or near stock?????

stock 09 M8 LE (153) with RK-TEK secondary riding at 5-7,000 ft turning 43-47 mph track speed on a climb at 7,400-7,700 rpm. I weigh 215 with all my gear on (35 lbs of gear). My buddys 07 M8 with a 162 couldn't match my himarks on the hills.

 

[DonoBBD]

where did they pull it from? Did you take down 68gram weights?

Pulling it out of the heal. Then down low in the primary the belt will slip a bit on engagement. This moves the mass center line out on the tip and will mph more too. You will see in time some groves in the primary down low but this is fine don't worry about it.

Don.

 

[Desperado]

How about a picture of the weight and where it was ground from. I would like to smooth up my engagement too. Need to see how much material they've been taking off. It would also be nice to know in grams how much weight it is that is taken off. thanks

 

[thumper450]

i would like to grind down some 68's to 67's

 

[DonoBBD]

Where the roller is running you will get a mark on the weight. This is center of the 1/2 inch flat spot grind. Then you do it again.

Each grind is best done with a band sander. The % of weight change is as follows. First grind flat spot is .0063% of start weight. Second grind is a total of .00945% of stock weight. So if you start with a 68 gram weight and do both grinds you will end up with a weight that is 67.357 grams. Each grind moves the mass center line out on the tip more. The first grind will make a stock weight shift like a dalton pro weight then the second grind will have it shift out better.

The two springs I have been using with this type of a grind is Cuttler Performance gold/white and purple/white. Stock cat springs will work too. If no rise in start rate in the primary spring your engagement will be lower.

This will get you two things 1) nice and smooth engagement and roller to weight clearance will get bigger by .040". 2) it will move the mass center line out on the tip more. Stock it is at 22/32 from the tip or .6875 then the first grind puts it to 20/32 or .625" from the tip just like the dalton weight out of the box and the second grind will give you 19/32 from the tip or .593" and most of the time with the CP gold spring will shift out.

This is the best stock part set up for the DDrive and is the trick for the M1000 and F1000 to hook up and not adding the extra shim.

Cheers Don.


Here is the pictures of the grind. IF you want to smooth out the grind you can to match up the weights and get them down that extra .3 of a gram.