Wow! 39 Grams of Unbalance: Witness clutch demo

[7perk]

Definitely the worst clutch I have ever balanced.

This is just a demonstration of how far out a clutch can be. This Ski-Doo 1000 cc is at an unbalance of 39grams. I will show you the clutch before and then I use temporary weights to give you an idea of what balancing the clutch can do for you. This is not the finished product just an example of the process I do before I add or subtract the weight to adjust the clutch to make it balanced, typically we remove weight to obtained a balanced clutch.

Check this out on youtube:
http://youtu.be/t48OmERPSy0

 

[sled_guy]

What RPM is the clutch spinning at?

sled_guy

 

[byeatts]

Definitely the worst clutch I have ever balanced.

This is just a demonstration of how far out a clutch can be. This Ski-Doo 1000 cc is at an unbalance of 39grams. I will show you the clutch before and then I use temporary weights to give you an idea of what balancing the clutch can do for you. This is not the finished product just an example of the process I do before I add or subtract the weight to adjust the clutch to make it balanced, typically we remove weight to obtained a balanced clutch.

Check this out on youtube:
http://youtu.be/t48OmERPSy0

Nice demo. Regardless of the skeptics you provide a necessary honest service.Bob

 

[7perk]

39 grams of unbalance

The RPM that we balance the clutches is 1240 rpm. Special Note: In the last 5 years we had only Ski-Doo clutch that was under 5 grams of unbalance in the front end. Therefore EVERY Ski-Doo clutch from the factory is out of balance. (they are averaging 15 grams of unbalance on the front end & I just did a 2012 and it was 21 grams out).

 

[byeatts]

The RPM that we balance the clutches is 1240 rpm. Special Note: In the last 5 years we had only Ski-Doo clutch that was under 5 grams of unbalance in the front end. Therefore EVERY Ski-Doo clutch from the factory is out of balance. (they are averaging 15 grams of unbalance on the front end & I just did a 2012 and it was 21 grams out).

i understand you also have a suggestion in relation to PTO TDC for the weight loss position?

 

[7perk]

39 grams of unbalance

Yes, if you send your clutch to me for balancing I will mark the clutch and tell you where to place it on the crank for the best position to reduce the crank unbalance, but just remember this only helps one side of the motor.
And for all those who have had their clutches balanced in the last few weeks I will reduce the price of the Engine Balance Kit (2007 thru 2011 800R) if you purchase the kit. Why? 1. Increase HP 2. Increase Belt life 3. Increase crank bearing life 4. Faster response time 5. Increase of 3 to 10 MPH

 

[BBP]

If the clutch is balanced, why do you need to index it on the crank?

 

[winter brew]

If the clutch is balanced, why do you need to index it on the crank?

Good question.

 

[7perk]

Primary Balancing

Indexing is just a slight help to the crank unbalance. It's just placing the lightest part of the clutch at the heavy part of crank unbalance. Special note the area that I've removed from the clutch is the area that is that .025 of runout from center line of the clutch. Which makes it lighter weigh wise in that area on Ski-Doo clutches when they are 10 to 30 grams of unbalance. Just remember the crank has 115 grams of unbalance that's 10 times the clutch unbalance.

 

[CBX]

what if both are balanced independently?

 

[weetee]

Indexing is just a slight help to the crank unbalance. It's just placing the lightest part of the clutch at the heavy part of crank unbalance. Special note the area that I've removed from the clutch is the area that is that .025 of runout from center line of the clutch. Which makes it lighter weigh wise in that area on Ski-Doo clutches when they are 10 to 30 grams of unbalance. Just remember the crank has 115 grams of unbalance that's 10 times the clutch unbalance.

Um, I'm not getting something. If the clutch is balanced (when spinning), how is there a "lightest part of the clutch"? If its balanced when spinning it should make no difference where you put it on your crank. It won’t counterbalance anything.

Unless:
-Run out puts the same weight out farther from center,
-which causes unbalance the higher the RPM,
-the more the RPM, the more the unbalance.
If thats the case, and your balancing at 1200 RPM, what happens at 8000 RPM. I still have run out. Wont the unbalance get exponentially worse? Wont the run out side, even though its lighter, still be the heavy part of the unbalance?

 

[7perk]

39 grams of Balance

As I've stated several times before unbalance DOES NOT change with RPM. Centrifugal forces increase with RPM increase. The crank on a 800R is 115 grams of unbalance per side at 1200 rpm & 8000 rpm but centrifugal force at 8000 rpm with 115 grams of unbalance = 922 lbs. of centrifugal force and the crank turns 125 times per second so you have a 922 lb. bowling ball at a certain angle equal & opposite on the 2 stroke crank assy. and that's why the bearings wear out and the crank breaks. Again a balanced clutch works any where on the crank but there is a place that helps with the 115 grams just on the PTO side of crank and it just helps a little.

 

[skibreeze]

That makes absolutely no sense to me.

 

[BBP]

It doesn't make sense to me either, unless the clutch isn't perfectly balanced. What part of the crank is heavy, the piston side or the counterbalance side?

 

[mx100]

I am hoping this thread continues. I have a RT 1000, and I am thinking a balance job would be a good thing to do. The only thing I am wondering, is if skidoo put the un-balance in it on purpose to off set the runout in the crank? Maybe there is a certain position to put the unbalanced clutch back on the crank after you take it off. I doubt it though.

A balance job can't hurt can it?

 

[WyoBoy1000]

makes sense to me, the clutch is heavier on one side because it is balanced, but it may be out of round meaning egg shaped or the material is heavier in one spot or another. The cranks can't be balanced alone, and the have a way of throwing there weight around, so you put the heavy side of the clutch to the light side of the mass of the crank and it helps or at least in theory. Has anyone had this done and can talk from experience.

 

[winter brew]

makes sense to me, the clutch is heavier on one side because it is balanced, but it may be out of round meaning egg shaped or the material is heavier in one spot or another. The cranks can't be balanced alone, and the have a way of throwing there weight around, so you put the heavy side of the clutch to the light side of the mass of the crank and it helps or at least in theory. Has anyone had this done and can talk from experience.

I think the part people (me included) are hung up on, is if the clutch is balanced, there is no longer a heavy side (or light side...or whatever), that's the whole purpose of balancing, to eliminate that.
And if there IS a heavy side, then the clutch is NOT balanced.
I am curious what Doo did to the '12's having the clutch indexed to the crank....perhaps purposely counterbalanced to counter-act crank pulse to lessen vibration?

 

[xpspenziv]

sounds like your putting an internally balanced balancer on a extenally balanced rotating assembly. How does he know the engine he doesn't have in front of him is unbalanced by 115 grams and where????? He doesnt.

not every piston weights the same.
ring wt and locating pin.
piston pin wt.

 

[xpspenziv]

.
I am curious what Doo did to the '12's having the clutch indexed to the crank....perhaps purposely counterbalanced to counter-act crank pulse to lessen vibration?

woodruff key maybe? 2-3 blank splines? like a dodge p/u 2 peice driveline. Only goes together 1 way.

 

[whitefish]

I am curious what Doo did to the '12's having the clutch indexed to the crank....perhaps purposely counterbalanced to counter-act crank pulse to lessen vibration?

So if that is true, balancing a clutch my not be beneficial.