Author Topic: Success - C12 drive sprocket 19 tooth issue  (Read 181 times)

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Joe L

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Success - C12 drive sprocket 19 tooth issue
« on: 10 October, 2021, 13:57:24 »

Reference - gear box drive sprocket (19 tooth)
I have rebuilt a 1958 C12 and incurred several problems along the way. The BSA Forum have helped with some of these issues so I thought I would post my recent success for other members who have experienced this problem.  The successful outcome will also benefit C10L and C12 owners.
I had found it impossible to find the relevant part for my C12 despite numerous phone deals to dealers and Google searches. It was whilst talking to a regular contact at Dragonfly that it was suggested I try a C15 drive sprocket (19 tooth). On receipt of this part I compared it with the original and found that the diameter of the C15 part was bigger - the C12 diameter being approx. 1.5 inches.
I managed, or should I say my wife, managed to locate an engineering company to grind it to the right diameter. Fortunately, the company, Delta Precision  Grinding were based in Ellesmere Port only 7 miles away so I was able to visit to explain my problem. The manager, Josef Wood, was very, very helpful. He would be only too pleased to talk to anyone needing similar help. His telephone number is 0151 355 1144.
Because the height of the two sprockets were different I made a 1mm washer/shim to bring the chain to the correct alignment with the rear sprocket.
All running good now. Thanks to everyone concerned.


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Re: Success - C12 drive sprocket 19 tooth issue
« Reply #1 on: 10 October, 2021, 20:09:51 »
Great result and good info. Goes to show that in an age where everything is online, there is nothing to compare with getting on touch with local firms and sorting face to face to resolve tricky issues.

Had a similar issue getting a new spline welded onto my gear selector.

Glad you got it sorted. Another one saved.