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Topics - Arthur

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Lightweights / BSA Dandy Aluminium Cylinder
« on: 02 February, 2017, 12:08:50 »
When launched at the 1955 Earls Court show, the BSA Dandy was advertised as using a chrome plated aluminium cylinder. Aluminium was needed to better dissipate the heat from the rear facing cylinder since cast iron has a much lower thermal conductivity. However, by the time it went into production in 1957, the accepted view was that the aluminium cylinder had been replaced by a cast iron one since BSA had failed to fully develop the aluminium chrome plating process by that time. Unfortunately, this change then led to cooling problems with the engine.

Intriguingly, I have Dandy engine DSE 365 which is fitted with a chrome plated aluminium cylinder. I'm not sure where the engine originally came from but it's engine number relates to a BSA Dandy produced in 1957 which seems to be at variance with the normally understood development history of the bike. It seems to suggest that the Dandy originally went into production with the chrome plated aluminium cylinder but was quickly changed to a cast iron one, presumably, due to premature wear of the chrome.

It would be good to hear from anyone with an early Dandy who might be able to shed further light on this issue or who has an engine with an aluminium cylinder?

Lightweights / BSA Beagle Rocker Feed
« on: 02 February, 2017, 07:47:54 »
Although the BSA Beagle 75cc engine looked like a small Triumph Tiger Cub engine, it was notorious in not being provided with a separate oil supply to the rocker boxes. This ultimately led to premature engine failures and the Beagle then being dropped from the BSA line up after just over a year of production.

One solution to the Beagle rocker box problem is to lubricate them by hand before each run out which is obviously less than ideal. I would be interested to know if anyone has implemented a better engineered solution to this problem which then makes the BSA Beagle a more practical bike to own.

Which BSA do you ride? / My Lightweights
« on: 30 January, 2017, 09:14:25 »
I might as well start with my 2 x lightweight BSA's which were fully restored last year.

Singles / B40 WD gear ratio
« on: 30 January, 2017, 08:51:47 »
I've assumed I have to re-start the previous topic from the old forum to continue with the discussion?

I had a quick look at one of my B40WD's and, surprisingly, it is fitted with a 19T gearbox sprocket rather than the standard 17T. I am still restoring this bike and have not yet had a chance to ride it but assume the previous owner was happy with the much higher gear ratio. My other B40WD has standard gearing which is much too low for my liking and I will almost certainly change to an 18T gearbox sprocket to improve things slightly.

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