Sprocket change

If the speedo drive is taken from a wheel, then altering the gearing will make no difference to the speedo reading.
If it is taken from elsewhere e.g. gearbox, then it might make a difference.
As you may have realised, I have absolutely no idea where the speedo drive is on a modern Bonneville (my '69 Bonnie was from the rear wheel if I remember correctly). But the above is a general rule of thumb.

 

The speedo is driven by the front wheel, so any sprocket changes wont affect the speedo.
Geoff

 

Hi Geoff slight correction here mate - the earlier Bonnys were cable drive off the front wheel but later ones (inc 2014) were a speed sensor off the gearbox, as such the change of sprocket does change the speedo reading.

 

As above + 1 as mines on the gearbox and a 2013 bike

 

Hi BL as I said somewhere else, I went from an 18 to a 19T on my 2010 T100 and all it changed was that the speedo read PERFECTLY correct, as opposed to reading slightly optimistic.

 

Doh, forgot they changed to canbus system,
Geoff