Another Crazy Zane Hypothesis ? Clutch Cush Rubbers.

[ghwallice]

I?ve been doing some research on getting a run of Zane clutch cush rubbers and rear wheel cush rubbers  manufactured.
Most of us with Zanes are not aware that there are cush rubbers in the Zane clutch basket, cos in the spare parts manuals there are no breakdowns and no part numbers. Same sort of setup as the Breganzes, but different sizes.
I was asked some months ago to fix a rattly 668 clutch, and on breakdown the rubbers were shrunken and hard. Based on the density scale used for rubber (what was the name of the scale? Not Rockwell..) they were a 90.

A new cush rubber for a Breganze measured 70. The 750S samples I took in measured about 80. The other air-cooled zane samples were above 85.

The rubber type used when exposed to above 100 C hardens rapidly and shrinks. Given that the air cooled run quite hot, up to about 125 C(?), this would explain the hardness as compared to the water cooled motors, which is limited to about 90 C (?).

So, in the aircooled motors would this lack of absorbtion in the clutch transfer to drivetrain/gearbox issues that are more pronounced than the water cooled motors?????

Thoughts, debate ect would be appreciated!

Regards, Greg

 

[Jo]

I?ve been doing some research on getting a run of Zane clutch cush rubbers and rear wheel cush rubbers  manufactured.
Most of us with Zanes are not aware that there are cush rubbers in the Zane clutch basket, cos in the spare parts manuals there are no breakdowns and no part numbers. Same sort of setup as the Breganzes, but different sizes.
I was asked some months ago to fix a rattly 668 clutch, and on breakdown the rubbers were shrunken and hard. Based on the density scale used for rubber (what was the name of the scale? Not Rockwell..) they were a 90.

A new cush rubber for a Breganze measured 70. The 750S samples I took in measured about 80. The other air-cooled zane samples were above 85.

The rubber type used when exposed to above 100 C hardens rapidly and shrinks. Given that the air cooled run quite hot, up to about 125 C(?), this would explain the hardness as compared to the water cooled motors, which is limited to about 90 C (?).

So, in the aircooled motors would this lack of absorbtion in the clutch transfer to drivetrain/gearbox issues that are more pronounced than the water cooled motors?????

Thoughts, debate ect would be appreciated!

Regards, Greg

Shore ..?

 

[huey]

Hi there... yes it is Shore Hardness measured with durometer
They are a modified rubber.......Could be worth speaking to Tina Pampernal at ERA Polymers Botany Sydney
  they did initial work on suspension rubbers more like a cast siliconebut tough for one of the after market suppliers

 

[GregT]

Urethane. Solves all ills - at least in cush drives.

For volume production of odd shapes, a mould and casting them is best.
Different shore hardnesses available too.

 

[ghwallice]

Urethane. Solves all ills - at least in cush drives.

For volume production of odd shapes, a mould and casting them is best.
Different shore hardnesses available too.

The rear wheel cush rubbers I am getting are coming from Europe, and are moulded and casted. The scale is called Duro - Shore A. I have ordered 80A (what does the A stand for??) c/w bonded steel inner ring as per oem. Getting a run of over 100 done, but not putting in final order until Tuesday to allow demand if required.

Still working on the Zane clutch cush rubbers that don't exist....

Regards, Greg

 

[GregT]

I'd imagine the A simply stands for the measuring scale used. Like Db(A) which is decibels measured on the common (A) scale.

At one point I was making a lot of RS125 cush "rubbers". Machined from urethane with a steel insert. Not hard to do, just time consuming. Someone somewhere is remaking them in rubber at a better price so I'm happy to not be making them now.

I've hand cut urethane clutch cush inserts for the 550/650/750 Kawasaki engine family. As the OE rubbers collapse, they develop a knock at idle. Usually cured by turning the idle up, LOL.

 

[AJ]

There are many scales of Shore hardness with A and D the commonly used ones. A for softer rubber and D for harder rubber. So Shore A 80 is approx Shore D 30. Gauges are readily available now on ebay etc.