Cush drive lubrication

[Ian]

Folks I’m putting my wheels back together after having them powder coated. When I took the back wheel apart there was so much muck and grease on it that it was hard to tell what is supposed to be lubed and what isn’t.

 

Everything is cleaned up now ready to go back together but there is no info in the manual on where you are supposed to put grease and where you are not.

 

Obviously the spline drive needs greasing, but does the hub that the Cush drive sits on also need greasing (see pic with screwdriver pointing at what I’m trying to describe)?

 

Also, are you supposed to grease the large diameter spacer in the second photo?

 

Any advice greatly appreciated

 

 

[Scud]

MartyNZ alerted me to this thread about the cush drive and has drilled out the rubber pucks. He can probably say more about it, but here is a link to the thread:

 

http://www.v11lemans.com/forums/index.php?showtopic=11820

 

I'm going to do this at the next tire change.

 

The wheels look great by the way. Looks like the tires are already on, but next time, you might think about using angled valve stems for easier access.

[Ian]

Good idea, i’ll remember that every time I check the tyre pressures now!

[MartyNZ]

... When I took the back wheel apart there was so much muck and grease on it that it was hard to tell what is supposed to be lubed and what isn’t.

Everything is cleaned up now ready to go back together but there is no info in the manual on where you are supposed to put grease and where you are not.

Obviously the spline drive needs greasing, but does the hub that the Cush drive sits on also need greasing (see pic with screwdriver pointing at what I’m trying to describe)?

Also, are you supposed to grease the large diameter spacer in the second photo?

The hub definitely needs to be greased. If the splined drive plate seizes from rust, then the cush drive cannot cushion any more. You can see grease distribution grooves inside the spline drive plate bore, so we know the designer thought this is important. Of course some grease will get in there anyway if you are generous with grease in the drive spline.

On my bike, I sprayed the rubber pucks and puck pockets with a thin layer of dry lube, and also on the large diameter spacer. The wheel stays clean, and the plate can still move in the wheel.

I drilled the rubber pucks with lots of little holes, and only refitted half of the pairs of pucks so the cush drive would be "cushier". 

 

Also, an odd effect of rubber is that it does not compress much. If you squeeze in one place, it will bulge out in another place, without the volume changing (Poisson's Ratio for rubber is 0.5). This tells me that the pucks will be cushier if they could squirm in in their pockets easily, so dry lube helps.

 

So to summarise, my bike rear wheel has: 

1. Half the pucks drilled, half discarded. (optional choice for you)

2. Dry lube on pucks, puck pockets, large spacer. (optional)

3. Grease in bore of drive plate. (must do)

[Ian]

MartyNZ thank you mate. Sounds logical. What type of dry lube did you use one the rubber dampers?

[MartyNZ]

MartyNZ thank you mate. Sounds logical. What type of dry lube did you use one the rubber dampers?

I used Sandstrom Lubricant, Solid Film, MIL-PRF-46147.

Molycote 321 is just as good.

But since anything is better than nothing, whatever molybdenum disulfide spray you can find in your local hardware store will be ok. Probably better actually, as the Sandstrom stuff I used should be cured at 60°C, (150°F), and I didn't bother.

 

BTW, I got this idea of drilling the cush rubbers from Greg Field, who knows stuff about Guzzis. As Scud mentioned, Greg posted here: http://www.v11lemans.com/forums/index.php?showtopic=11820

I agree with him that the V11 is improved, and the drive train should last longer, with a cushier cush drive.

But I don't share his view that engine braking causes damage to the wheel drive spline. I think that each 530cc piston slamming torque down the drive train every engine rev is the main reason for spline wear.  

[LowRyter]

So what is the reason to drill holes in the rubber in cush drive?  It seems like it would flex more and cause the rubber to deteriorate. 

[Lucky Phil]

So what is the reason to drill holes in the rubber in cush drive?  It seems like it would flex more and cause the rubber to deteriorate. 

Yes my question also. Manufacturers generally spend a lot of time and money on finding the correct shore rating for things like cush drive rubbers and suspension bushes, I say generally. What evidence does MartyNZ have that his cush drive mod is worth doing and Guzzi got the cush rubber hardness rating wrong?

 

Ciao  

[Kiwi_Roy]

I must have read the same article on drilling the pucks, I did mine early on, 5 years and about 30k later they still looked fine.

Rubber is non compressible 

[Lucky Phil]

I must have read the same article on drilling the pucks, I did mine early on, 5 years and about 30k later they still looked fine.

Rubber is non compressible 

Mine are stock and after 18 years and 42,000 klms look fine also as do the drive splines on the wheel and the drive shaft. So whats the advantage?

 

Ciao

[Jim in NZ]

"Mine are stock and after 18 years and 42,000 klms look fine also as do the drive splines on the wheel and the drive shaft. So whats the advantage?"

 

The original design was OK, but the rubbers are very hard. I didn't drill mine, but I took out every alternate rubber wedge. I also regularly clean the whole cush drive and grease the centre bearing every 10,000km service. The advantage is that you can feel that the cush drive is a bit softer every time you change gear, with less abrupt take-up of the power. This must (by my reasoning) be kinder to the entire drive train from gearbox to tyres.

 

Jim.

[LowRyter]

OK,  the idea of drilling the cush rubber is to take shock out of the driveline for the purpose of a smoother ride or preventing driveline failure.  Perhaps that contributed to my cracked my transmission?  

 

And all along I was blaming my right wrist.  

[docc]

Seems the idea is all about cushioning the drive line. I doubt it would impact the gearbox case cracks.

 

That would be a ll those wild-eyed wheel stands!

[Jim in NZ]

Yep, the idea is about cushioning the drive line, and I'm sure it will reduce stresses on all components during hard acceleration, wheelies, clutchless gear changes, unintentionally jiggling the throttle as you go over a bumpy road, and so on.

I suspect that stresses in alloy components can be cumulative, so maintenance (cleaning and greasing) of the cush drive will be worth it over the long term even if you decide not to drill the rubber wedges or remove some of them.

[Lucky Phil]

I dont really like the idea of removing rubbers because it means that the torque is now transmitted through only half the metal drive blades.

 

Ciao