Author Topic: Double disc speedometer driveon a late hub with no flats Q?  (Read 485 times)

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Offline Don R

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Double disc speedometer driveon a late hub with no flats Q?
« on: August 24, 2023, 03:31:43 PM »
  I'm thinking I need to cut down a tabbed drive hub and mill spaces for the tabs into the right rotor hub, are there any other hot tips?  I have 2 aluminum rims, both of them are on hubs with no flats. from 76A's probably. 
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Offline HondaMan

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #1 on: August 24, 2023, 05:24:35 PM »
When I did it: I modified a speedo-drive flange and screwed/tapped 2 tiny screws into the stock hub to hold it still on the hub, circa 1972.
Caveat: this lasted about 30k miles before it sheared one, then both, of the tiny screws! I ran for thru 1976-78 with first a "slow" speedo, then none at all, until 1979. I replaced it all with new parts in 1980 and went back to 1 disc.
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Offline BenelliSEI

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #2 on: August 24, 2023, 06:25:17 PM »
  I'm thinking I need to cut down a tabbed drive hub and mill spaces for the tabs into the right rotor hub, are there any other hot tips?  I have 2 aluminum rims, both of them are on hubs with no flats. from 76A's probably.

Don….. I like your idea; sounds like a good one.

Offline scottly

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #3 on: August 24, 2023, 07:18:46 PM »
Don, do you mean like this? ;D
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Offline PeWe

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #4 on: August 24, 2023, 08:38:11 PM »
Something like this?
For hub for tabs and not.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline CycleRanger

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #5 on: August 24, 2023, 09:37:42 PM »
This is a K0 front hub with the speedo drive.

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Offline BenelliSEI

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #6 on: August 25, 2023, 05:43:41 AM »
Don, do you mean like this? ;D


Simple and elegant! I like it……

Offline MauiK3

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #7 on: August 25, 2023, 07:53:14 AM »
I used Yamiya's kit, works great.
1973 CB 750 K3
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Offline Bankerdanny

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #8 on: August 25, 2023, 10:18:31 AM »
Don,

This is what I did when I installed the Lester and F3 front end on my F1. The rotors are CB550. Initially I ground 2 pockets into the rotor. But after talking to people here, decided I didn't need to do that. I used an angle grinder to cut off lip of the drive so that it just sits inside the rotor. The fork legs keep it from rotating. Multiple thousands of miles with no apparent issues.
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Offline Don R

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Re: Double disc speedometer driveon a late hub with no flats Q?
« Reply #9 on: August 25, 2023, 02:04:53 PM »
  Thanks for the ideas!
  I actually have a K0 drive but wanted to use one of these aluminum rims, neither have flats on the hub.  Both have nice or new spokes. I did find a rotor that came with two full depth notches already done so I cut a drive down and was going to weld the tabs back on.   
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.