“WHICH PARTS FROM OTHER BIKES FIT THE 961”

TonyA said:

I thought about delrin , Finding the right size might be a problem. If you can make your own on a lathe ?

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If I had a good one to get measurements from I can make them if you wanna test a set out.

lcrken said:

Delrin is a rigid plastic, not an elastomer. No shock absorbing capability.

Ken

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Correct. It is.
but.
What’s the need of shock absorbing for when it’s chain driven and the chain has slack.
I know it’s not a good comparison, but I use rod ends and or delrin in my track car to eliminate the deflection in my suspension.

lcrken said:

I haven't really looked for a better price. Mine came with the BST wheels. I have noticed that the common price for most suppliers of the BST rubbers is $95 for a set of 5.

For comparison, the set of Gale Speed rubbers I ordered from Japan cost about $63, including shipping.

FWIW, a 6" piece of 1.25" OD, .625" ID Shore 80A polyethylene rubber tube costs US$21.32 from McMaster-Carr, plus shipping, and should make 9 or 10 rubbers, so a real bargain if one can get the machining right.

Ken

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Machining them isn’t a problem. Just need a new one to measure from.

Voodooo said:

Correct. It is.
but.
What’s the need of shock absorbing for when it’s chain driven and the chain has slack.
I know it’s not a good comparison, but I use rod ends and or delrin in my track car to eliminate the deflection in my suspension.

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Well, when you consider that the whole reason for a cush drive is shock absorption, and all the major bike manufacturers seem to agree that they are needed, it seems counter-intuitive to basically eliminate them. In your rod ends you are trying to eliminate deflection, but in a cush drive, deflection to absorb shock is what you want. So, you could be right that it's not needed, but that would mean that all the manufacturers are wrong. Somehow I think that's unlikely.

Ken

TonyA said:

Hello Ken , I am OK with that price , Just asking that's all. They will last longer , everyone that has BST wheels says so. if we can find a suitable replacement for the Talon spoked cush rubber great ! If I have to get my rear wheel hub machined , well I only have to do it once !

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Agreed. I think if I were planning to use the Talon wheels for anything, like maybe on another bike, I'd try to do the conversion to BST rubbers. But at the moment I don't have any plans for the wheels, so it's pretty much just curiosity that's driving my interest.

Ken

lcrken said:

Well, when you consider that the whole reason for a cush drive is shock absorption, and all the major bike manufacturers seem to agree that they are needed, it seems counter-intuitive to basically eliminate them. In your rod ends you are trying to eliminate deflection, but in a cush drive, deflection to absorb shock is what you want. So, you could be right that it's not needed, but that would mean that all the manufacturers are wrong. Somehow I think that's unlikely.

Ken

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I’m not arguing with the manufacturers. I understand that the crush drive reduces stress. But sometime things can be approved on.
Perhaps a thin delrin outer sleeve with a rubber or urethane crush with a delrin or steel insert.
The outside delrin sleeve would keep the urethane crush bushing from deflecting and deforming as would the center insert.

"The Talon rubbers are 31.6 mm OD, 20 mm ID, and 10.35 mm width."

I get 31.4 x 19.5 x 10.15 on unused cush rubbers, but a bit hard to be exact on something which flexes.
It is a slight push fit over the 20.3 dia bolt head so that seems about right.
OD and ID was to the main section, not the slight ridge in the middle.

Edit - numbers updated after I checked all 5, and took a bit more care.

Well here are my last pack of genuine Norton items ( check out the Cush drive rubbers)from last summer, the Cush drive rubbers were out of stock for just a few days but I did get the whole lot sent very quickly

They must have done a roaring trade in cush rubbers and fuel tank bolts.

ntst8 said:

"The Talon rubbers are 31.6 mm OD, 20 mm ID, and 10.35 mm width."

I get 31.4 x 19.5 x 10.15 on unused cush rubbers, but a bit hard to be exact on something which flexes.
It is a slight push fit over the 20.3 dia bolt head so that seems about right.
OD and ID was to the main section, not the slight ridge in the middle.

Edit - numbers updated after I checked all 5, and took a bit more care.

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The Delrin will have no give and needs to slide into the rear wheel hub and over the bolt head . So a sliding fit , and yes I will be happy to try out the set of Delrin cush drive spacers. !

lcrken said:

Agreed. I think if I were planning to use the Talon wheels for anything, like maybe on another bike, I'd try to do the conversion to BST rubbers. But at the moment I don't have any plans for the wheels, so it's pretty much just curiosity that's driving my interest.

Ken

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Need is driving my interest .

TonyA said:

The Delrin will have no give and needs to slide into the rear wheel hub and over the bolt head . So a sliding fit , and yes I will be happy to try out the set of Delrin cush drive spacers. !

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If you can provide a good new spacer or accurate measurements I’ll make you some to test.

Cush drive bushings are not like car suspension bushings (if that's what you're thinking as far as using delrin), and going with harder cush drive bushing is not advisable. In fact it would be counter productive to what they're designed to help do.

Cush drive bushings are designed to reduce stress from engine torque damaging other components during gear changes or in throttle changes. A delrin cush drive bushing would be as bad or worse than a dried up rubber cush drive bushing. When the rubber damper becomes old and hardens or wears out, the changes in load on the drive chain instigated by changes in throttle position or changing gear can cause snatchiness in the power delivery. Loads particularly on the drive chain can be massively increased in these conditions, increasing the risk of breakage or of contact with the swinging arm resulting in damage. Perhaps more pointedly the sudden transfer of force to the rear tire can cause momentary loss of traction (lock or spin) resulting in small changes of direction or at worst total loss of control.

If you've ever hopped a rear wheel when braking hard into a corner, or felt the rear end start to come around when accelerating out of a bumpy corner where you are losing traction, harder cush drive bushings would only make it worse.

If anything, you want to increase the rate of vibration absorption. Here is a product that race teams are using to reduce resonances in swing arms: https://hhrperformance.com/b-159828-supreme-technology.html

lcrken said:

I've been trying to find something suitable, but so far no exact equivalent. I'm assuming you have the Talon spoked wheels, not the BST. The rubbers for the BST wheel are readily available, but not so for the Talons. The Talon rubbers are 31.6 mm OD, 20 mm ID, and 10.35 mm width. Those are my measurements on a used rubber, so they might not be exactly right for fresh ones, but close enough for looking for replacements. The closest I've found are universal rubbers from Gale Speed, at 32x16x11.

https://japan.webike.net/products/1513392.html

They would probably fit in the cush drive carrier, buy would require you to find bolts with a 16 mm head diameter to fit. Or it might be possible to remove the steel bush in them, which would probably give you the needed 20 mm ID. I've ordered a set to see if they will fit, and I'll post the results.

Another option for those so inclined, is to make your own. You can buy 1.25" polyurethane rubber tube in Shore 80A hardness, and machine the rubbers from them.

https://www.mcmaster.com/9697k145-9697K245

That's what I use to make them for my home made cush drives. I measured the stock rubbers at Shore 75A hardness, so the 80A is a good match. Or you can make some simple molds and just pour them from 80A molding urethane. Lots of info on pouring your own urethane parts (motor mounts, etc.) on youtube. I haven't tried it, but it looks pretty simple.

Ken

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EXCELLENT post, Ken. Thank you. So what would the possibility be to insert metal tubing if we made our own from neoprene stock?

Britfan60 said:

EXCELLENT post, Ken. Thank you. So what would the possibility be to insert metal tubing if we made our own from neoprene stock?

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No reason we couldn't. I did notice that one of the manufacturers (I don't recall which one) of this style of rubber described the steel bush as "hardened steel". But I wouldn't attach a lot of significance to that.

Ken

Hi, Not sure if this has been discussed but I recently sent Talon an email enquiring about the 961 cush rubbers. Apparently they are available to get here in Aus via the importer and to quote TCDR1x5. On an aside.... my main 30amp fuse and holder under the tank melted this morning..pushed 4k home... anyone have an alternate replacement that's more robust by chance?

Hi Paul,
That’s god news re the Cush drive rubbers availability in Aus. Do you know who the importer of Talon parts is.
Thanks

Sorry I should have posted;

You will require TCDR1x5, our Australian importer can assist with a purchase.
JOHN TITMAN RACING SERVICE PTY LTD
0061 73245 7499
www.jtr.com.au
sales@jtr.com.au

Looked up the importer and not far from me, phone number little different from one supplied:

Unit 3 / 38 -44 Enterprise St
Cleveland, QLD 4163
07 3286 4862

Thanks mate, much appreciated

Bakepl said:

Sorry I should have posted;

You will require TCDR1x5, our Australian importer can assist with a purchase.
JOHN TITMAN RACING SERVICE PTY LTD
0061 73245 7499
www.jtr.com.au
sales@jtr.com.au

Looked up the importer and not far from me, phone number little different from one supplied:

Unit 3 / 38 -44 Enterprise St
Cleveland, QLD 4163
07 3286 4862

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Aussie speedway and Leicester Lions legend....