Couple of Bantam build questions please,

 Is it a good idea to swap around the existing 2nd and 3rd gears, I found a diagram of how to do this on the web but if that lowers second then what happens to third gear. Is it instead better to buy the aftermarket second gear set which is I believe 20/27 ?

Which ignition system and crankshaft weight is the one to get

All BSA Bantam engine build hints and tips welcomed

Edited January 28, 20206 yr by trialsrfun

6 hours ago, trialsrfun said:

Couple of Bantam build questions please,

 Is it a good idea to swap around the existing 2nd and 3rd gears, I found a diagram of how to do this on the web but if that lowers second then what happens to third gear. Is it instead better to buy the aftermarket second gear set which is I believe 20/27 ?

Which ignition system and crankshaft weight is the one to get

All BSA Bantam engine build hints and tips welcomed

This lowers the 2nd and 3rd gears then a big jump up to the top gear I have used this for 18 years and the bike has done many pre 65 Scottish events (around 8). The bike has only ever broke down once in all of the years me and my daughters have abused it. Pvl ignition with no weight ts 185 piston standard clutch.

Edited January 28, 20206 yr by wiggy
Dad isn't good with computers...

Hi Wiggy a great story of a bike that has obviously given lots of pleasure to you and your family.

Thank you for the information regarding the gears is second low enough to be useful in sections if you need a bit more speed than 1st

See attached picture showing all of the ratios, the swapped second gear can be used in sections ok depending on your sprocket sizes and rider weight . The best thing about the low second gear kit is the higher top gear!

Hope the spread sheet makes sense 

Best set up I have found for a D14 includes the gear switch as above, Electrex World ignition, B175 centre plug head, Rex Caunt 187 cc big bore piston kit, standard clutch Drayton exhaust and air box, Amal Premier carb, 12 t primary sprocket  Hope this helps. Cheers 

10 hours ago, ikb said:

See attached picture showing all of the ratios, the swapped second gear can be used in sections ok depending on your sprocket sizes and rider weight . The best thing about the low second gear kit is the higher top gear!

Hope the spread sheet makes sense 

Thanks for the spreadsheet ikb very interesting and Paulmac for the set up you have.

It would be interesting to know who first realised that the Bantam gears could be interchanged to give alternate ratios. I read that one major reason why BSA did not produce a trials version of the Bantam was because of the high cost of manufacturing gear clusters as used on the works bike's, yet surely BSA must have known that this could be achieved using the part's they already had.

Edited January 29, 20206 yr by trialsrfun