Compensator wear
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Joined: Dec 2005
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From: poway
I have to agree with Kingglide on this one. Compensators only purpose is for noise vibration and harshness issues. Keep in mind, ours are really the only bikes out there that have a compensator, and there are plenty of engines out there that make as much and more power. Remember also that sportsters typically (at least up t the rubber mount era, and maybe even then, I haven't checked) use a solid crank sprocket attached to the alternator rotor.
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From: Globe AZ
First, To appreciate a comp, there are a few things to take into account.. Is the motor rubber mounted? What is the weight of the bike? How much torque does the motor put out? What RPM is the peak torque produced at?
I have a 113 ci Evo softail bobber that probably weights a little less than 550 lbs. It has a 3 inch BDL belt drive primary. Motor makes 124 hp and 120 fp tq in 4th gear (back when 4th was the gear to run bikes in).. The BDL does not have a comp. At 2500 rpm it makes about 100 fp When does it vibrate the worse? When I roll the throttle on at 2500. I can feel each power pulse, of the motor pulling forward. As the Rs go up the motor power pulses smooth out, mainly because of flywheel mass but at upper RPM motor imbalance takes over and it vibrates a bit more.. Run this bike hard and parts fall off.. Turn signals spin like Linda Blair's head, speedometers and tachometers die (on my 4th or 5th and they need replacing). What drops the vibration? I can cruise at 3200 rpms, steady throttle and vibrations are considerably less. Roll the throttle on and the bike shakes.
I don't know of any twinks that are not running a comp and making decent HP. I've got an 07 EG that makes at least 110/110, and while it's on it's 4th comp, vibes have always been minimal. I can hardly feel the power pulses at 2500. It's a heavier bike that's rubber mounted but the pulses are almost non existent compared to the 02 RK I have which has the early comp. It likely makes about 105/105 but I've not dynoed the recent build.
I have a 113 ci Evo softail bobber that probably weights a little less than 550 lbs. It has a 3 inch BDL belt drive primary. Motor makes 124 hp and 120 fp tq in 4th gear (back when 4th was the gear to run bikes in).. The BDL does not have a comp. At 2500 rpm it makes about 100 fp When does it vibrate the worse? When I roll the throttle on at 2500. I can feel each power pulse, of the motor pulling forward. As the Rs go up the motor power pulses smooth out, mainly because of flywheel mass but at upper RPM motor imbalance takes over and it vibrates a bit more.. Run this bike hard and parts fall off.. Turn signals spin like Linda Blair's head, speedometers and tachometers die (on my 4th or 5th and they need replacing). What drops the vibration? I can cruise at 3200 rpms, steady throttle and vibrations are considerably less. Roll the throttle on and the bike shakes.
I don't know of any twinks that are not running a comp and making decent HP. I've got an 07 EG that makes at least 110/110, and while it's on it's 4th comp, vibes have always been minimal. I can hardly feel the power pulses at 2500. It's a heavier bike that's rubber mounted but the pulses are almost non existent compared to the 02 RK I have which has the early comp. It likely makes about 105/105 but I've not dynoed the recent build.
You have pretty much proven our points that the comp is more for rider comfort than a mechanical necessity. There is little argument that the existing comp is a crap design, but there is also little room inside the primary to use a different design of comp. As kingglide stated, the springed hub in an automotive clutch disk serves essentially the same purpose, and yet this is replaced every time that the disk is changed. There are cars out there (BMW for one) that use a multi-piece flywheel with one side sprung to the other, but these are also failure prone (Ive broken one or two), and again, there isnt room for this style of damping. It all really comes down to what level of harshness you can accept for durability. If you can live with a few more vibes, then bin the compensator, and go with a solid hub (would be my choice), or know that the part WILL need to be refreshed on a recurring basis, as there is a wear component to its use. As for the Sporty not using a comp due to rpm range, Im not so sure on that. My sporty was a buzzy bastard to begin with, but the revs werent that much higher than my Ultra. What I think it boils down to more is the intended usage. Sportys dont tend to see big mileage days, so the vibes are less intrusive. Touring bikes tend to be more geared to the comfort side, so have softer suspensions, more driveline damping (cush drive on rear wheel) and other things to take out the annoying NVH that will tire you out in the long haul
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,900
Likes: 8,007
From: poway
You have pretty much proven our points that the comp is more for rider comfort than a mechanical necessity. There is little argument that the existing comp is a crap design, but there is also little room inside the primary to use a different design of comp. As kingglide stated, the springed hub in an automotive clutch disk serves essentially the same purpose, and yet this is replaced every time that the disk is changed. There are cars out there (BMW for one) that use a multi-piece flywheel with one side sprung to the other, but these are also failure prone (Ive broken one or two), and again, there isnt room for this style of damping. It all really comes down to what level of harshness you can accept for durability. If you can live with a few more vibes, then bin the compensator, and go with a solid hub (would be my choice), or know that the part WILL need to be refreshed on a recurring basis, as there is a wear component to its use. As for the Sporty not using a comp due to rpm range, Im not so sure on that. My sporty was a buzzy bastard to begin with, but the revs werent that much higher than my Ultra. What I think it boils down to more is the intended usage. Sportys dont tend to see big mileage days, so the vibes are less intrusive. Touring bikes tend to be more geared to the comfort side, so have softer suspensions, more driveline damping (cush drive on rear wheel) and other things to take out the annoying NVH that will tire you out in the long haul
You can't compare the spring cushions to the springs in a friction plate. They are not progressive dampers like on HD. Also the car motor has more cylinders. Power delivery is much smoother.
Not sure you can say the current comp design is bad. Is there any that has had an issue with the new M8 comps?
.
Banned
Joined: May 2018
Posts: 4,576
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From: Viet Vet, crossroads
Max Head flow-
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
Seasoned HDF Member
Joined: Jan 2006
Posts: 11,471
Likes: 2,998
From: Charleston, SC
Max Head flow-
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
First hint, it does not contain not a wound spring. The assembly moves in two directions centered between ramps under constant diagram spring pressure.
It takes approximately 150-175 foot pounds to bottom out the comp moving forward or backward. If the engine is delivering a typical 100 foot pounds, the comp will remain near center mid ramp on the forward side.
Last edited by lp; Feb 12, 2019 at 06:49 AM.
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Joined: Nov 2006
Posts: 5,889
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From: East Coast, USA
https://en.wikipedia.org/wiki/Belleville_washer
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,900
Likes: 8,007
From: poway
Max Head flow-
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
We have all beat this subject to death in this thread and others.
I will just ask you this from an engineering viewpoint.
Look at leverage -The dia of the comp is not as big as the clutch,
nor will it carry the load!
If If it was a single plane cljutch,
It would have to be 14 across dia to absorb the Total TQ of the HD engine .
look at the leverage of that little comp, It has what 3/4 to perhaps one inch of movement? (at the most)
Depending on the model and I have not measured them all.
Just so you know that little thing just wraps up the spring at very low RPM.
When the clutch is being let out after that it is pegged doing nothing until you let off the throttle.
AT speed and RPM it is getting whacked and shocked as if it was not there. (if you blip the throttle)
Think about that for awhile.
Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
Try this -
Put your bike in gear so the engine does not roll over , put your strap wrench, socket, on the comp.(or whatever means you want to duplicate to be the engine power)
I will guarantee you will be shocked how EZ it is to move before it takes up the slack against the engine.
It is a sloppy piece of work and does almost nothing.
From the engineering standpoint of friction or break away, you will readily understand my persistence in this argument.
I look fwd to your assessment.
When these things fail that is the noise that is heard , the absolute slack being taken up after the acceleration of the crankshaft has speeded up.
That shock is way worse than a comp deletion.
Put your bike in gear so the engine does not roll over , put your strap wrench, socket, on the comp.(or whatever means you want to duplicate to be the engine power)
I will guarantee you will be shocked how EZ it is to move before it takes up the slack against the engine.
It is a sloppy piece of work and does almost nothing.
From the engineering standpoint of friction or break away, you will readily understand my persistence in this argument.
I look fwd to your assessment.
When these things fail that is the noise that is heard , the absolute slack being taken up after the acceleration of the crankshaft has speeded up.
That shock is way worse than a comp deletion.
Last edited by Kingglide549; Feb 12, 2019 at 01:27 PM.
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Seasoned HDF Member
Joined: Dec 2005
Posts: 19,900
Likes: 8,007
From: poway
Try this -
Put your bike in gear so the engine does not roll over , put your strap wrench, socket, on the comp.(or whatever means you want to duplicate to be the engine power)
I will guarantee you will be shocked how EZ it is to move before it takes up the slack against the engine.
It is a sloppy piece of work and does almost nothing.
From the engineering standpoint of friction or break away, you will readily understand my persistence in this argument.
I look fwd to your assessment.
When these things fail that is the noise that is heard , the absolute slack being taken up after the acceleration of the crankshaft has speeded up.
That shock is way worse than a comp deletion.
Put your bike in gear so the engine does not roll over , put your strap wrench, socket, on the comp.(or whatever means you want to duplicate to be the engine power)
I will guarantee you will be shocked how EZ it is to move before it takes up the slack against the engine.
It is a sloppy piece of work and does almost nothing.
From the engineering standpoint of friction or break away, you will readily understand my persistence in this argument.
I look fwd to your assessment.
When these things fail that is the noise that is heard , the absolute slack being taken up after the acceleration of the crankshaft has speeded up.
That shock is way worse than a comp deletion.
Not shocked. I understand how the comp works. Every time I break a crank-nut loose, I use a jam bar. The bar locks the sprocket. I put a 1 1/2 inch socket or #70 torx on the crank nut / bolt and hang on the breaker bar. The crank moves to the point where the springs compress. It moves easily at first but get progressively stiffer as the sprocket slides up the cam until the nut/bolt breaks loose. I can watch the cam move and the springs compress on a later comp. The thing is that when the cam is at the bottom of the ramp where it's flat, there is only friction from preload and the sproket can move. That's how it works. As it spokes or sprocket nubs move up the ramp the force of the springs are multiplied by the tangent of the angle of contact.
Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
Then you see and feel my point, there is not very much resistance there.
This pretty much proves what I have been trying to explain.
When they are worn out, they shock the crank more than if they were not there at all.!
Simple kinetics really, as this truly shows what a whimpy snuber this comp thing is.
As I have said Many times B4,- if this thing is all that stands between a broken crank or not HD truly sucks.
To date, no one anywhere has ever proven a comp deletion is what broke their crank.
You all carry do what you like.
This pretty much proves what I have been trying to explain.
When they are worn out, they shock the crank more than if they were not there at all.!
Simple kinetics really, as this truly shows what a whimpy snuber this comp thing is.
As I have said Many times B4,- if this thing is all that stands between a broken crank or not HD truly sucks.
To date, no one anywhere has ever proven a comp deletion is what broke their crank.
You all carry do what you like.