Norton parts lists, as usual follow a little behind..On the 16H, they show the change as between contracts C9062 and C10217 but in fact, period photos suggest that it occurred a little earlier - in the forst half of 1941, under contracts C7353 and C7576..Big 4s from around S3000 ought to have had the later type S433B speedo and cable.
The fact that these few Irish machines were delivered from British contracts would suggest that they initially had non-illuminated, non-trip units...Do we know what the pre-war Irish M20s had ? If they had trips then this is probably where they came from.
Hi Rik
There is no evidence yet to indicate that bsa K series or any of the early bsa W models supplied in 39 or 40 to the iDF had trip option speedometers fitted
Br
Job
