Getting at the cush drive

[slug]

So I'm trying to get to the rubber blocks in my cush drive, but I'm stuck.

 

I got the six buttonheads from hell out without any trouble, and the silver pie plate is off, but I can't go any further. For the life of me I can't get the steel plate with the rear drive splines & vanes out.

 

I've looked at a few other threads but they're either unclear how to do it, or their links to special instructions/tricks are outdated.

 

Tips & tricks from the peanut gallery?

[tmcafe]

There's some kind of ring seal between the ss plate and the cush drive (something like tan fiber). You removed that, right? Then you remove the cush drive with two diametrically opposed flat screwdrivers tips. Watch for the edge of the alu side of the cush drive. I taped my scredriver tips with duck tape. There's some kind of suction between the cast iron part and the one where the rubber pieces sit in, and the top part is also heavier. But once you do it, you realize it's a piece of cake.

[slug]

Aces!

 

That and a couple squirts of WD-40 between the splines on the plate and hub-tube ((for lack of a better term) did the trick.

 

Thanks!

 

I'm doing a huge ride-prep on the bike and I'm finding a lot of things on the bike were grease inadequately or not at all at the factory. Grrrr.

[tmcafe]

Glad it worked out. You may want to do Greg's "Swiss cheese" mod on the rubber wedges. I did mine and left half out as well.

[slug]

Glad it worked out. You may want to do Greg's "Swiss cheese" mod on the rubber wedges. I did mine and left half out as well.

 

Yep. Did it but left all the wedges in. We'll see how it feels. If anyone is interested, I measured the durometer of the wedges and they averaged at 72 (they're about four years old.)

[gstallons]

If you don't own a parts and or service manual, get a cd or dvd version. I bought one from guzzitech ( I think) for a cd version and it has been one of my best investments. You can print one page or the entire manual.This is better than thinking or guessing when disassembling or upon reassembly whan all those parts look so unfamiliar. "Look before you break". If you get the pages dirty throw them away and print some more.

[dlaing]

Yep. Did it but left all the wedges in. We'll see how it feels. If anyone is interested, I measured the durometer of the wedges and they averaged at 72 (they're about four years old.)

Thanks Slug! that is useful info!!!

I was considering making new wedges of urethane, but I would have to find a urethane softer than 70A.

I am sure it exists, but it would have been easier to find an 80A urethane.

[pasotibbs]

There's some kind of ring seal between the ss plate and the cush drive (something like tan fiber). You removed that, right? Then you remove the cush drive with two diametrically opposed flat screwdrivers tips. Watch for the edge of the alu side of the cush drive. I taped my scredriver tips with duck tape. There's some kind of suction between the cast iron part and the one where the rubber pieces sit in, and the top part is also heavier. But once you do it, you realize it's a piece of cake.

I think I did it by turning the wheel upside down and popped the cush out by dropping it a couple of inches onto some carpet.

[savagehenry]

I think I did it by turning the wheel upside down and popped the cush out by dropping it a couple of inches onto some carpet.

Thanks for the suggestion! Tried the "very carefully with two screwdrivers" method, no dice. Turned it over and dropped it flat a few times and the plate popped right off. Once again, this forum is worth every dime!

[Skeeve]

Yep. Did it but left all the wedges in. We'll see how it feels. If anyone is interested, I measured the durometer of the wedges and they averaged at 72 (they're about four years old.)

 

Cool! That was a project I was about to undertake myself. 72A or D?

[dlaing]

Cool! That was a project I was about to undertake myself. 72A or D?

It would have to be A. Trust me, I am a four time college drop out.

But according to people with expertise on the forum, it is chromoly hard and should be measured not in durometers but in the Rockwell C scale

[Skeeve]

It would have to be A. Trust me, I am a four time college drop out.

But according to people with expertise on the forum, it is chromoly hard and should be measured not in durometers but in the Rockwell C scale

 

That's why I'm thinking it's 72 on the Shore D scale, which equates to about 95 on the A...

[dlaing]

That's why I'm thinking it's 72 on the Shore D scale, which equates to about 95 on the A...

The people that said they were chromoly hard were exaggerating AND misleading.

In the old thread I suggested Urethane at about 50 (A) would be about right for a replacement, but you suggested 72 or higher.

I think you are correct that 50A would be too soft. Guzzi nearly nailed the rubber softness right off the bat at 72A, but MAYBE 65A would be more ideal.

These are NOT hard like hockey pucks.

In the old thread, DOCC said his were about as hard as automotive tire rubber.

In the old thread, I said,

"I pressed on the rubber with a screw driver and estimated the durometer at about 60-70A.

No I don't have a durometer, but it was harder than my motorcycle tire, and softer than a 75A skateboard wheel.

I wedged one in a door and it compressed very nicely. Probably about 50% compression with maybe one pound of force on the 30inch door."

[Skeeve]

The people that said they were chromoly hard were exaggerating AND misleading.

In the old thread I suggested Urethane at about 50 (A) would be about right for a replacement, but you suggested 72 or higher.

I think you are correct that 50A would be too soft. Guzzi nearly nailed the rubber softness right off the bat at 72A, but MAYBE 65A would be more ideal.

These are NOT hard like hockey pucks.

In the old thread, DOCC said his were about as hard as automotive tire rubber.

In the old thread, I said,

"I pressed on the rubber with a screw driver and estimated the durometer at about 60-70A.

No I don't have a durometer, but it was harder than my motorcycle tire, and softer than a 75A skateboard wheel.

I wedged one in a door and it compressed very nicely. Probably about 50% compression with maybe one pound of force on the 30inch door."

 

I think the durometer of solid pucks will need to be lower; it's likely the combination of higher durometer and no room for the pucks to compress [bulge sideways when compressed lengthwise] that makes them inadequate in the stock application. That's where drilling the holes in them comes in: it makes room for them to deform into...

[dlaing]

I think the durometer of solid pucks will need to be lower; it's likely the combination of higher durometer and no room for the pucks to compress [bulge sideways when compressed lengthwise] that makes them inadequate in the stock application. That's where drilling the holes in them comes in: it makes room for them to deform into...

That makes sense. The ooozability improvement factor from drilling may be more important than the hardness. But there certainly is some room to oooze out the left side and into the corners.

If you replaced the pucks with plasticene, you could mash it to paper thinness.

But rubber has more integrity. Softer rubber would comply better.

It does not take much drilling to let it compress more symmetrically, which should be beneficial.

I drilled in from the end of the wedge, hypothesizing that it will develop an air cushion or air damping if it leaks.

If it leaks and then suction cups on rebound, it may be counter productive, but doubt that is happening.

In any case it allows some theoretically beneficial oozing.