Making a Cushier Cush Drive

[Greg Field]

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?

 

 

Impressing the neighbors is always more important than extending the life of parts.

[jimbemotumbo]

Twisting. Heat. Rubber. Lube. Cush. Hardness. It all sounds good.

This thread makes me want my sporty back so I can try this.

 

Anybody have a spare V11 I can work on?

[Guest ratchethack]

Impressing the neighbors is always more important than extending the life of parts.

Touché , Greg!

[Pierre]

Touche, Greg!

Hack, my post wasn't "aimed" at Greg. He knows that.

 

Thanks for dropping in, though - right on cue.

[Pierre]

Impressing the neighbors is always more important than extending the life of parts.

Thanks Greg. I was pretty sure you'd understand my dilemma.

 

FWIW I'm having a passel of titanium wedges fabbed as we speak. Having "mad Luigi" do some extras in case anyone else is interested. Just let me know if you want 'em regular or "swiss cheesed."

[Guest ratchethack]

Hack, my post wasn't "aimed" at Greg. He knows that.

 

Thanks for dropping in, though - right on cue.

Por nada, mi compadre.

 

Aimed at Greg? No comprende.

 

Long as we're speculating on wot Greg understands, I reckon he understands wot everyone else here more'n likely does, except perhaps y'erself, Pierre -- Your neighbors, and anyone else more'n likely, don't pay enough attention to notice how you corner into your driveway and couldn't care less -- even though it would appear that you'd just love it if they did.

 

But then again, maybe throttle steering backwards might raise an eyebrow . . .

[Pierre]

Mastery of the obvious performed on nearly a daily basis.

No shit.

[Skeeve]

D'you s'pose the compound used in say, hoses or tires, for just 2 examples, are the same compounds you'd find in a cush drive?

 

Buna-N, in various subvarieties [aka "Neoprene"] unless I very much miss my guess.

 

In all fairness, Dave Laing is right: a properly-formulated urethane part would be a far better solution*, as it would have better longevity & more importantly, consistency over the product lifespan than the stock rubber cush drive wedges.

 

OTOH, the likelihood of getting such a parts change made by Piaggio/Moto Guzzi is unlikely, given the combined factors of price/finding a new supplier/planned obsolescence objectives.

 

On the 3rd hand, the Guzzi buna wedges have about 10x the bearing surface of equivalent cush drive parts on similar-size J-brand offerings, & those seem to take about a minimum of 10 years of hard riding to decay to the point of needing replacement, from what I've heard/read/experienced.

 

So w/ some judicious applications of Swiss Cheese Engineering per Greg's instructions, the cost effectiveness of having to the replace them when the rubber does finally go south means that the stock units are probably the best solution for the job, not just the only one.

 

I might suggest taking the wedges and leaving them to soak overnight in Armorall or sillycone grease or something prior to replacing them in the hub, as a means of increasing their squishiness & shock absorbtivity down the road.

 

Thanks, Greg!

 

*altho' the correct durometer is probably 72 or higher, not down in the 50s!

[docc]

Twisting. Heat. Rubber. Lube. Cush. Hardness. It all sounds good.

This thread makes me want my sporty back so I can try this.

 

Anybody have a spare V11 I can work on?

 

 

Straighten up there, boys. You're being moderated by a guy with a German bike.

 

And if we're gonna have vampires, let's have Catherine DeNeuve and Suasn Sarandon from The Hunger. I'd be helpless . . .

[pete roper]

When I first read about the suggestion of either removing half of the rubbers or drilling 'em several years ago I was skeptical as to either it's wisdom or effect. Basically being a cynical bastard I wondered if it was just another 'wonder Cure' thought up by someone with too much time on their hands. Anyway, to cut a long story short, being one such person I decided that I'd simply try it. I was lucky, my cush drive plate came out very easily this isn't usually the case. Now if ever there was a bike that needs a decent cush drive it's my SP. This has a full house LeMans top end with a cam developed for midrange torque but it also runs an Ambasador flywheel and an 8/33 final drive off a late model Cali. If anything was going to punish it's driveline then this is the bike!

 

Anyway, I removed half the rubbers but didn't drill the remaining ones. I have to say I was astonished by the difference it made. It really was VERY noticeable how much smoother it made the whole power delivery and specially gear-changing seem.

 

On V11's and the like with their lighter flywheels the need for a cush drive is significantly reduced but there again 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.

 

It's interesting to note that the *new* models with the single sided swingarm now have a rubber cush drive incorporated in the shaft. One of the things most often noted by people who hop on a new Griso, Breva, Norge is the 'Clunkiness' of the final dive system and gearbox. this is purely a result of the very stiff nature of the rubber in the shaft cush drive, after 20,000 Kms mine is now no noisier than any other Guzzi and certainly less so than f'rinstance a Carb Sport.

 

Rubber is a perfectly acceptable medium for such a part. Why in the name of all that's holy would you want to swap something that's simple, is cheap and works for something that is complicated, failure prone and expensive???? The type of rubber used for the original 'Pie Slices' could certainly be better chosen or, simply drilled as Greg has at the factory! But that would involve cost and labour so it ain't gunna happen so we're stuck with what we got!

 

I personally think it's a damn fine idea and I will be doing it to my Scura in time. Needless to say my 'Vert doesn't need such an unsophisticated and primitive device

 

Pete

[richard100t]

How do you get to the cush drive once those buttonhead screws are removed? Theres that gear in there & it aint moving without further instructions! lol

[pete roper]

I use a two jaw puller under the splines on the cush plate and press on a coin or washer placed over the centre of the bearing. Note that if it is very tight this will probably damage the bearing so it might be a good idea to replace 'em both at this time. If it's rusted up go at it with penetrating oil and a lot of heat from a butane torch like Greg did.

 

pete

[richard100t]

I use a two jaw puller under the splines on the cush plate and press on a coin or washer placed over the centre of the bearing. Note that if it is very tight this will probably damage the bearing so it might be a good idea to replace 'em both at this time. If it's rusted up go at it with penetrating oil and a lot of heat from a butane torch like Greg did.

 

pete

I cant even get to the cush plate on mine. What I'm looking at is flat smooth & shiny & is under a gear. I take it the cush plate is under this part that I cant seem to move? I'm sure theres something that needs to be done to access the cush plate that I havent seen yet.

Nevermind Pete....you are right in what you said! I just put a flat blade screwdriver under either side of the cush plate & it lifted right out.

 

Now that I have my cush plate out it looks like brand new with 21,000 miles on it Theres some sort of grease in there & the rubber seems soft & pliable to me. I'm sure the cush plate hase never been off before as the bike only had 300 miles on it when I got it. Could it actually have been lubed at the factory?

[Guest ratchethack]

. . . There's some sort of grease in there. . .Could it actually have been lubed at the factory?

Is it anything like marinara sauce?

[richard100t]

Is it anything like marinara sauce?

It didnt taste like marinara! I've been thinking about it for a few minutes & I always put too much axle grease on the rear axle when I had the back tire off. My theory is Mandello left mine dry like everyone else but some of that axle grease worked its way in around the cover & lubed it. Thats what it looked like to me anyway. Well my mind is at ease now after I actually got a look at this famous so called rusty dry cush drive! lol Honest to Gawd, it looked like it just rolled off the showroom floor it was so pristine.

Maybe greasing the axle every other oil change would be a good idea for routine maintenance