Making a Cushier Cush Drive

[dlaing]

Since the rubbers are not chromoly hard, nor even ebonite hard, <_ i suspect that urethane would be a waste of time as the rubber is softer than all but softest urethanes.>

But maybe the friction disk could be improved on????

 

I'm only a little less baffled now. True, the ring appears to be a, say, fiber washer or 'fibre' gasket of sorts. Yet, there is no doubt friction as evidenced by the wear pattern etched in the "Plate With Gearing" (Shop Manual F10).

What I wonder is; did Luigi plan this to have an ideal damping effect?

 

 

In my case, the surface was polished smooth which is what I would expect with a fiber washer intended to be slippery. I'd worry about abrasion if there were any sign of it. As it was, I left it dry to avoid viscous friction.

Assuming Luigi is a faithful worshipper of Dry Clutches, dry is probably how he intended it, and for it to wear substantially might take 300,000 miles. In Luigi I Trust. (sometimes)

[docc]

I'm not sure we should trust that everything that came dry on our Guzzi ought to be left dry . . .

 

I wouldn't lube the fiber ring if I had to do it again. Of course with the moly I used, the ring will be forever slipperier even after I wipe it down to be sure there is no viscous friction or grit-trapping effects.

[dhansen]

For what it is worth.................. I'd like to add another for doing this simple mod to your cush drive. A little heat on the six buttonhead screws worked like a charm and they all came out without damage. I was lucky and the drive plate came out with little fuss as well. Since I'm not the most petite rider in the world, I decided to drill and reuse all six pairs of rubbers, well greased.

 

Managed to get a real ride in this morning and difference is quite apparent shifting up and down.

 

Try it, you'll like it!

 

Dennis

[velofish]

I just did this, too. Drilled one big and three smaller holes into all the rubbers, (reused all of them). My cush was dry but not rusty so I lubed the hell out of it.

 

Noticeable difference. It doesn't turn the sport into a 'vert, but the downshifts are smoother.

 

I used an ez-out on all the bolts and used regular head bolts, not those damn buttonheads, to replace them.

 

fish

[Robban]

Greg, don't you find this enhanced "rubbery" action you're recommending interferes with the "feel" needed to "back er' in" and throttle steer through corners? A tough performance vs longevity call IMHO. I'd personally hate to give up impressing the neighbors as I throttle steer into my drive way, just to save a few splines. Whadaya' think?

Dear Sirs,

please enlighten me if I´m wrong, but I´m of the persuasion that a cushdrive is supposed to take the "backlash" of the piston speed difference from tdc/bdc to max speed of the piston and since the MG engines have a fairly short stroke I can not see why the cushdrive should have anything to do with beating the splines to pieces especially since there is a cushdrive built into the gearbox itself?

Please enlighten me?

Best regards

Rob

[Guest ratchethack]

Rob, your approach is a reasonable one (to a point). The beating of the splines (as Greg noted in his opening post) occurs from idle RPM on up to all conditions of normal operating RPMs. At idle, it's the unevenly staggered firing sequence of the V-twin that takes it's toll, regardless of the oversquare bore/stroke. As The Maestro Hisself explained way back in post #94 in this thread:

. . .As the flywheel accelerates and decellerates between power strokes the plates will thrash bavk and forth on their splines and this will eventually cause *stepping* and wear on the splines leading to poor engagement and disengagement of the clutch and in extreme cases 'Creep' when the clutch is engaged at a standstill.

 

This thrashing is only really a problem at low engine speeds and is due to the 270/430 degree firing order of the V twin motor. For this reason it is unwise to set your idle speed low, (Guzzi recommend 1200RPM for a reason.) . . .

pete

Now at operating RPMs, typically running up and down thru the gearbox whilst accelerating and decelerating, (and completely independent of the low RPM variations in angular velocity due to the unevenly staggered firing order noted by Pete) the alternating "power on" and "power off" modes of driveline forces ALSO take a toll on the drive splines. A well maintained "softer" than OE hub cush drive with properly lubed drive splines will tend to ease the impact and result in less spline wear at all RPMs. As Pete has also noted, the "stack o' washers" cush drive in the gearbox seems to be of relatively questionable (possibly negligible?) benefit.

 

Hope this helps.

[Robban]

Rob, your approach is a reasonable one (to a point). The beating of the splines (as Greg noted in his opening post) occurs from idle RPM on up to all conditions of normal operating RPMs. At idle, it's the unevenly staggered firing sequence of the V-twin that takes it's toll, regardless of the oversquare bore/stroke. As The Maestro Hisself explained way back in post #94 in this thread:

 

Now at operating RPMs, typically running up and down thru the gearbox whilst accelerating and decelerating, (and completely independent of the low RPM variations in angular velocity due to the unevenly staggered firing order noted by Pete) the alternating "power on" and "power off" modes of driveline forces ALSO take a toll on the drive splines. A well maintained "softer" than OE hub cush drive with properly lubed drive splines will tend to ease the impact and result in less spline wear at all RPMs. As Pete has also noted, the "stack o' washers" cush drive in the gearbox seems to be of relatively questionable (possibly negligible?) benefit.

 

Hope this helps.

 

Thanks for the clarification Ratchethack.

So now I have to start worrying about the splines in my "noncushed" 1100 sport?

Rob

[Guest ratchethack]

Por nada, mi compadre.

 

The non-cushed hubs have been a concern, as noted in previous threads. Yes, a non-cushed hub will take a toll on the entire driveline that the cushed hubs will not -- hence the hub cush drive's raison d'être. But no cause for undue worry as long as it's otherwise being properly maintained.

 

It's a relative kinda thing. Can't hardly ride 'em if you can't bring yourself to accept the wear of use as intended. . .

 

EDIT: Then again, The Maestro has also opined thusly early on in this thread:

. . .the *new* face cam shock absorber *spring*, (It's a tower of belvile washers!) in the gearbox is about as forgiving as a block of concrete making a decent cush at the rear wheel even more vital.

 

But waddayagonna do? You could spend a lot of time worrying about it, "upgrade" to a cush drive hub. . . or just ride it.

[Greg Field]

Because of all the expensive spline parts on Guzzis, I advise that the rider modify his riding style if necessary to minimize the use of compression braking, especially violent compression braking. This is easpecially important on the bikes that lack a cush drive.

[gavo]

Because of all the expensive spline parts on Guzzis, I advise that the rider modify his riding style if necessary to minimize the use of compression braking, especially violent compression braking. This is easpecially important on the bikes that lack a cush drive.

 

 

If this is so and since we use both sides of a spline this logic dictates we don't accelerate hard either, so do I just ride around like grandma or just push the bike into the shed because I'm afraid it might break <_>

[gstallons]

Easily remedied, ease off the throttle before 270 and 450 degrees of every other crankshaft revolution to ease this shock.

[Greg Field]

You have only one system to supply positive acceleration: Your engine. Use it.

 

You have two systems to supply negative acceleration: Engine compression and brakes. Use your brakes and you will take a great shock load off of your splines.

 

When in doubt, think of the following: Engines are for going; brakes are for slowing.

[dlaing]

You have only one system to supply positive acceleration: Your engine. Use it.

 

You have two systems to supply negative acceleration: Engine compression and brakes. Use your brakes and you will take a great shock load off of your splines.

 

When in doubt, think of the following: Engines are for going; brakes are for slowing.

I accelerate regularly from 0-60 MPH in about 5 seconds, but figure if I rev the heck out of the engine on downshifts it would probably take over ten seconds to get from 60-10MPH.

Yes, getting close to redline when dropping gear is dangerous and will wear your splines down more quickly, but accelerating WOT close to redline is much more damaging to the splines. The amount of torque at the splines is much greater during acceleration.

One reason the cush design is bad is that it is engineered as if the accelerating and decelerating forces were the same.

I drilled only one hole in each decelerating cush(to soften the cush) and no holes in the accelerating cushes (to resist bottoming out). Made sense to me...

I suppose Greg sees many more V1100s with worn splines.

Do the spline wear in both directions equally? If so, it may not be the torque wearing things out so much as the pulses and or the "lash-related" sudden driveline forces during changes from accelerating to decelerating and vice versa.

[Greg Field]

Dave:

 

On a V11, are you more likely to exceed the traction available to your tire by:

 

1) Cranking on the throttle

 

2) Downshifting and dumping the clutch with the throttle off.

 

Personal experience has shown me that #2 is more likely.

[gavo]

dumping the clutch on the downshift is just bike abuse and asking to have the back wheel lock up if not judged right, this is why its best to blip the throttle. Try changeing gears on your manual car without using the clutch, smooth changes can be achived simply by getting the revs right which means u must bring the revs up to what they would be if u where doing said speed in next lowest gear, ask a trucker with a roadranger gearbox. Try easing the clutch out when shifting up or down smoothness is the key and your bike ,body and wallet will thank you