Tuesday, November 15, 2016

Gearing the Gold Star

With the Gold Star finally running sweetly the next item on the list was sorting out the gearing. Fitting a Bob Newby clutch altered the primary gearing to 2 to 1. With the 350 motor running a RRT2 box and 19 tooth on the gearbox sprocket it meant that the bike could barely pull top gear on the flat and pulling away in first was a tricky business if pointing up hill.

I had been planning to swap to a 17 tooth on the gearbox and called up Gold Star specialist Phil Pearson to see if he had one. Turns out Phil does not stock sprockets but he was free with his advice and recommended going down to 16 teeth and suggested Autocycle Engineering as the people to call. Phil also gave some decent advice on making the motor more tractable - as a highly tuned and rev happy 350 it doesn't really suit my 6 foot free 15 stone frame. The advice boiled down to it being unlikely that I would ever be content with the 350 and would forever be revving and shifting gears. The bright side though is that a conversion to 500 or 600cc is a lot more reasonably priced than I had expected so I am starting to save my pennies....

Road test time and the 16 tooth sprocket is indeed exactly the right one. The bike is still fairly tall geared but is now slightly more civilised and manageable. There's still plenty of shifting to be done to keep it on the boil but it feels like it is now working as BSA intended.

Next and hopefully final step is to sort out the electrics.

One 16 tooth sprocket form Autocycle Engineering. An
unusual size but they came up trumps and it arrived quickly.

Ready for the new sprocket. Alloy engine / gearbox plates
are fitted. There are quite a few non standard and lighter
parts on this bike, it is however still a heavy old beast.

Autumn has properly arrived but it is peculiarly warm. Hello
global warming! Test ride and all is good, the change of gearing
has made a very substantial improvement.

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