Author Topic: 1955 A7 Shooting Star Gearing  (Read 540 times)

Offline Andrew J

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1955 A7 Shooting Star Gearing
« on: 07.03. 2012 23:14 »
Hi All,

I am about to restore a 1955 shooting star and it just happens that a friend of mine has just finished a resto on 1955 shooting star as well.
I have an original BSA data book for 1955 and it states that the engine sprocket is a 19 tooth, clutch 43 tooth, gearbox 19 tooth and rear sprocket 42 tooth.
My friend set up his bike to those ratios and rode the bike and found that it was reving very hard and seemed to need another gear, he has now gone and purchased 20 tooth sprocket for the engine and will try it soon.
Would like to know what other people have experienced with their bikes.

Regards Andy


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Re: 1955 A7 Shooting Star Gearing
« Reply #1 on: 08.03. 2012 08:18 »
I have a 1955 Shooting star with standard gearing which I built in the mid 90's.  I'm on the large size! If you change from a 19 to a 20 tooth this will make about 5% difference to the gearing so at 3000 r.p.m. you might be doing 52 mph instead of 49 m.p.h. (for example) so you're not likely to notice much difference. I would recommend going up to a 20 tooth, particularly if you're not of heavy build, as my bike copes with my weight no problem but it does struggle if carrying a pillion (total 30 stone plus so you can't blame it!). If you use all the Shooting Star internals, i.e. high comp pistons and 357 cam you may find the bike has a tendency to 'pink' under heavy load - fitting a larger front sprocket could make this marginally worse, but if this is a problem it's easy to convert back to standard.