Dynamo drive sprockets

strider · Post by **strider** » Mon Oct 08, 2012 11:48 am

My '47 G80 Engine sprocket has 21 tooth primary drive, and 17 tooth dynamo drive. (matching the 17 tooth sprocket on the dynamo itself) But I have noticed that there are Crankshaft sprockets with differing numbers of teeth on the dynamo drive sprocket.
Is 17 teeth correct for my bike? And what is the reason for other sizes of sprocket being available?
Obviously it would alter the speed that the dynamo is driven at, but what advntages are there to that?

en7jos · Post by **en7jos** » Mon Oct 08, 2012 1:16 pm

quote:
Obviously it would alter the speed that the dynamo is driven at, but what advantages are there to that?

Quite handy for charging the battery at lower engine revs if the dynamo speed is increased (especially if the bike has been converted to 12v with an electronic reg and hence more volts are needed).

Have you consulted the owners instruction manual for your bike to check the correct (or at least standard) numbers of teeth? The first few pages usually have all sorts of useful info like that.

Regards, James

strider · Post by **strider** » Mon Oct 08, 2012 2:14 pm

Thanks James. My Instruction Manual only lists alternative sprocket sizes in the drive train, not mentioning number of teeth on the dynamo part of the sprocket.
I follow what you mean and I'll think about going up one tooth.
I need to get a new dynamo drive chain and it seems likely that an extra tooth might need an extra link in the new chain.

Samuel · Post by **Samuel** » Mon Oct 08, 2012 9:38 pm

Up a tooth on engine sprocket or down one on dynamo sprocket surely ?

strider · Post by **strider** » Mon Oct 08, 2012 9:50 pm

Thats what I meant. Up one tooth on the dynamo driving set of teeth on the crankshaft dual sprocket.