The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: snowbeard on 15.10. 2008 20:22

Title: clocks for a scrambles tranny drive speedo?
Post by: snowbeard on 15.10. 2008 20:22
So I am beginning to think that having either a speedo or a tach would be nice.  I have the brass drive from the mag for the tach, but have taken it off since I have no dial or cable, why wear it out, eh?

so I realized that my speedo drive is off the bottom front of my tranny.  it's a '57 spitfire scrambler with the original SC. T2 transmission (at least the cover is stamped XX over STD which I am told is the designation)

(http://img211.imageshack.us/img211/7155/kickergeartrannysidete2.gif)

can anyone tell me what drive ratio I need?  the bike is a rider, not a restoration by far, so I think I am alright with a repro just to have a readout before the lights start flashing!!

thanks
Title: Re: clocks for a scrambles tranny drive speedo?
Post by: bsa-bill on 15.10. 2008 22:08
Looks like you need to spend some cash on that kickstart pinion *whistle*

All the best - Bill
Title: Re: clocks for a scrambles tranny drive speedo?
Post by: snowbeard on 16.10. 2008 01:07
oh thanks, Bill  *smil*  that was actually one of the very first things I fixed on this bike, flushed the tranny really really well, then replaced both the kickstart rachet and the return spring. 

but good eye  ;)
Title: Re: clocks for a scrambles tranny drive speedo?
Post by: dpaddock on 16.10. 2008 16:49
my '57 Spit has a Smiths SSM 5007/02A magnetic unit with a nominal calibration of 1600.
Actually, Mark Bohman dialed it in to suit my rear tire rolling radius, so it's pretty much spot on.