Ring Gear on Primary Clutch
- Thread starter lilduke
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SidewaysInto3rd
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Aren't the etec clutches balanced to the crank ? Hence, you can't just slap on the clutch, you need to line up the big circle on the clutch with the mark on the crank (or maybe it's the little circle ...)
So if you take your clutch off and start changing it's balancing, you are actually messing up the balancing of your engine
So if you take your clutch off and start changing it's balancing, you are actually messing up the balancing of your engine
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Caper11
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Makes sence, the clutch is essentially a flywheel. Heavier rotating mass will store more energy (torque) for the hole shot.
I removed my ring gear on my 09, didn't like what I was feeling, went back on.
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Summitdoorule
Active member
Yes... You are correct!!!... Not sure why anyone wants to mess with there clutching???...
pfi572
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takethebounce
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Not entirely correct. The clutches are indexed to the crank.
The clutch sub assembly's are balanced then assembled and balanced complete. The heaviest spot on the clutch is marked and installed lining up with the mark on the stub. The line on the stub lines up with the pto rod.
This reduces vibration, it doesn't mean it is balanced to the crank because the cranks are not necessarily balanced and trued to start with. Indexing works but the indexing location could also change as the clutch runout changes. Make sense?
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If the clutch is balanced complete as you say, how can it have a heavy spot to mark?
takethebounce
Active VIP Member
BRP tightened their tolerances but it isn't perfect.
They could have left a heavy spot on purpose as well and doing so reduces the vibration when indexed. Are they in fact balanced to a higher degree which they released a bulletin in 2012, or are they simply finding the heavy spot and marking it? Sounds less expensive to assemble and locate heavy spot and mark with a circle, call it balancing than actually balancing it.
I am not a Doo engineer so I have no idea why they wouldn't strive to have a perfectly balanced clutch. That is if that is even possible. At rest the clutch may balance but when shifting in and out I am not sure it remains the same.
Regardless the ring gear remains. With all the dampening and added mass to the TRA it makes me question more than just the clutch. Just a negative side effect to a 800 twin I suppose.
Removing weight reduces the inertia mass. It works well on small two stroke bike motors and even larger bores to have that mass. I am guessing it works the same for the twins.
They have spent enormous amounts of money on the etec. I am sure they managed to figure out a few things.
As a thought, when removing the ring gear, rpm should build quicker, then requiring additional pin weight to keep from over rev. More pin weight the better?
Snow already!
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They could have left a heavy spot on purpose as well and doing so reduces the vibration when indexed. Are they in fact balanced to a higher degree which they released a bulletin in 2012, or are they simply finding the heavy spot and marking it? Sounds less expensive to assemble and locate heavy spot and mark with a circle, call it balancing than actually balancing it.
I am not a Doo engineer so I have no idea why they wouldn't strive to have a perfectly balanced clutch. That is if that is even possible. At rest the clutch may balance but when shifting in and out I am not sure it remains the same.
Regardless the ring gear remains. With all the dampening and added mass to the TRA it makes me question more than just the clutch. Just a negative side effect to a 800 twin I suppose.
Removing weight reduces the inertia mass. It works well on small two stroke bike motors and even larger bores to have that mass. I am guessing it works the same for the twins.
They have spent enormous amounts of money on the etec. I am sure they managed to figure out a few things.
As a thought, when removing the ring gear, rpm should build quicker, then requiring additional pin weight to keep from over rev. More pin weight the better?
Snow already!
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oler1234
Active VIP Member
Just to shed some light, but if you order a brand new etec long block from BRP... It does not have that white index mark on the crank.
takethebounce
Active VIP Member
My short block did. Why would it on a short block but not on a long block?
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oler1234
Active VIP Member
Got me. No index mark or anything else.
one buddy of ours lost a couple bolts when changing out ramps at the cabin one day. So I pulled the CV Tech PowerBloc 80 clutch off the big bore and threw it on his etec for the day. The clutch alone is 4lbs lighter with ring gear. Vs a tra. It ran not only smoother but rpmed quicker and maintain belt engagement to almost 3500rpm going downhill. You could literally feel how much more connected it was over the TRA. So i think the white mark is a bit of a gimmick and more about engine efficiency, sorta like indexing the plugs.
one buddy of ours lost a couple bolts when changing out ramps at the cabin one day. So I pulled the CV Tech PowerBloc 80 clutch off the big bore and threw it on his etec for the day. The clutch alone is 4lbs lighter with ring gear. Vs a tra. It ran not only smoother but rpmed quicker and maintain belt engagement to almost 3500rpm going downhill. You could literally feel how much more connected it was over the TRA. So i think the white mark is a bit of a gimmick and more about engine efficiency, sorta like indexing the plugs.
takethebounce
Active VIP Member
I wonder if the one you saw was old stock? I had a dealer installed 2012 etec done in February/March. It has the index mark on the stub.
The ring gear alone doesn't weigh much, but rotating mass is like 7 lbs for every 1 lb or something like that. That makes a difference. Fly wheel weight helps but I don't think the fly wheel is the best solution.
Maybe someone can find a way to measure the gyroscopic forces of the motor and its components. Too much fly wheel weight can go so far as to alter how a bike handles, makes it harder to move around corners due to angular momentum. Maybe the XM would be more flickable with half as much fly wheel weight.
I don't believe indexing is a gimmick. There is merit to the idea of finding the best location for weight on the crank to reduce vibration. What doesn't help is all the variables that are ever changing with that process.
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The ring gear alone doesn't weigh much, but rotating mass is like 7 lbs for every 1 lb or something like that. That makes a difference. Fly wheel weight helps but I don't think the fly wheel is the best solution.
Maybe someone can find a way to measure the gyroscopic forces of the motor and its components. Too much fly wheel weight can go so far as to alter how a bike handles, makes it harder to move around corners due to angular momentum. Maybe the XM would be more flickable with half as much fly wheel weight.
I don't believe indexing is a gimmick. There is merit to the idea of finding the best location for weight on the crank to reduce vibration. What doesn't help is all the variables that are ever changing with that process.
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tex78
Active VIP Member
On my xp ptek I indexed the crank to clutch... Think it's say 7 o clock it made a huge difference both open and idle
I marked crank with peen spot and clutch
I marked crank with peen spot and clutch
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