new sprocket

comnoz · Jun 28, 2016

Cool, fresh back from the anodizer, a new sprocket for the back of my bike. Just in time for the trip to Quincy.

cjandme · Jun 28, 2016

Show off,,,,, :evil: ,,,, just kidding Jim, you're right though, it is waay cool :mrgreen:

comnoz · Jun 28, 2016

cjandme said:
Show off,,,,, :evil: ,,,, just kidding Jim, you're right though, it is waay cool :mrgreen:

Well you are correct, I am showing off.

I am pretty happy with the fact that making that sprocket is now almost a push button and watch operation.

The programming has been challenging particularly since the sprocket is larger than the Y travel on my CNC machine so co-coordinating the 4th axis to actually cut it out without re-positioning the blank was a project.

cjandme · Jun 28, 2016

Jim, I have a question for you. (you probably already answered it in a previous thread regarding belt drives, but I don't remember) , anyway which hub are you using for that awesome sprocket? Is it a modified stock Mklll with factory lockheed caliper and rotor ?

comnoz · Jun 28, 2016

cjandme said:
Jim, I have a question for you. (you probably already answered it in a previous thread regarding belt drives, but I don't remember) , anyway which hub are you using for that awesome sprocket? Is it a modified stock Mklll with factory lockheed caliper and rotor ?

It's a stock MK3 hub with a custom sprocket carrier.

The brake is a CNW Brembo disk but I am using a button caliper from Vintage Brake and a mount of my own design.
I prefer a very weak rear brake as I have crashed too many times by over-applying the rear brake in a panic situation. I'm not sure you could lock the rear wheel even by standing on the pedal. Jim

Deets55 · Jun 28, 2016

I'm not sure you could lock the rear wheel even by standing on the pedal. Jim[/quote]

I get the same feeling on my stock rear brake on my MKIII :shock:

Great job on that sprocket Jim.

Pete

Fast Eddie · Jun 29, 2016

Will you be marketing a kit Jim??

comnoz · Jun 29, 2016

Fast Eddie said:
Will you be marketing a kit Jim??

Maybe someday,

I still need to come up with a better way of making front sprockets. Right now they are way too labor intensive to sell reasonably. Jim

Stephen Hill · Jun 29, 2016

Jim, I am interested in the tooth profile on the sprocket you made. Your sprocket has a more distinct flat at the tip of the tooth, which is "longer" than the stock sprocket. What is the thinking?

Stephen Hill

Matchless · Jun 29, 2016

Jim,

What is the width & pitch of the belt you are using, & what mileage do you get from each belt?

Martyn.

splatt · Jun 29, 2016

comnoz said:
The brake is a CNW Brembo disk but I am using a button caliper from Vintage Brake and a mount of my own design.
I prefer a very weak rear brake as I have crashed too many times by over-applying the rear brake in a panic situation. I'm not sure you could lock the rear wheel even by standing on the pedal. Jim

So you have gone around in a big fancy circle and reproduced the qualities of the STD drum brake again,

lcrken · Jun 29, 2016

splatt said:
comnoz said:

The brake is a CNW Brembo disk but I am using a button caliper from Vintage Brake and a mount of my own design.
I prefer a very weak rear brake as I have crashed too many times by over-applying the rear brake in a panic situation. I'm not sure you could lock the rear wheel even by standing on the pedal. Jim

Click to expand...

So you have gone around in a big fancy circle and reproduced the qualities of the STD drum brake again,

But with much lighter (unsprung) weight than the drum brake.

Ken

comnoz · Jun 29, 2016

Matchless said:
Jim,

What is the width & pitch of the belt you are using, & what mileage do you get from each belt?

Martyn.

I am using a Polychain belt. It is a 14mm pitch and a 20mm width.
I have never worn out a belt -only damaged them -so it's hard to say how long one could run.

First belt failure was when the sprocket packed up with salt after a few trips across the big salt puddle getting to the pits at Bonneyville.

The last belt failure was because the guide plate on the front sprocket came loose and wore the heads from the flathead screws that held it on. Then the plate got caught and wadded up and cut the belt. There was around 12,000 miles on that belt.

I found that the outer guide plate was not needed so I eliminated it and welded the inner guide plate to the sprocket so I shouldn't have to worry about that any more.

Last weekends 4 corners rally. I now have the belt replacement down to about 30 minutes.

comnoz · Jun 29, 2016

Stephen Hill said:
Jim, I am interested in the tooth profile on the sprocket you made. Your sprocket has a more distinct flat at the tip of the tooth, which is "longer" than the stock sprocket. What is the thinking?

Stephen Hill

I run a belt. Jim

Stephen Hill · Jun 29, 2016

Thanks Jim. How do you get the clearance at the front sprocket for a belt? Many bikes can just barely run a 530 chain.

Stephen Hill

comnoz · Jun 29, 2016

Stephen Hill said:
Thanks Jim. How do you get the clearance at the front sprocket for a belt? Many bikes can just barely run a 530 chain.

Stephen Hill

The area behind the clutch is cut out to clear the sprocket and belt.
That also makes it possible to replace the belt without pulling the inner chaincase.
All that needs to be removed is the outer cover , the clutch basket and the bottom of the LH shock. Jim

PS- After a call from John Snead, who has the equipment needed to make front sprockets -it looks like a kit may become a reality sooner that I thought.

Nater_Potater · Jun 30, 2016

comnoz said:
PS- After a call from John Snead, who has the equipment needed to make front sprockets -it looks like a kit may become a reality sooner that I thought.

I know it's early in the game, but do you have a ballpark cost? Thanks to your thread repair job on my bike's head, the chain is now the sole cause of oil splatters on my ride.

comnoz · Jun 30, 2016

Nater_Potater said:
comnoz said:

PS- After a call from John Snead, who has the equipment needed to make front sprockets -it looks like a kit may become a reality sooner that I thought.

Click to expand...

I know it's early in the game, but do you have a ballpark cost? Thanks to your thread repair job on my bike's head, the chain is now the sole cause of oil splatters on my ride.

Somewhere between 500 and 5000.

No not really.

new sprocket

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