Speedometer was a bit tired. Dad said it never worked properly, if at all, so the mileage could be way out. If it is the original the bike has done at least 62500 miles	Case was a bit rusty	The dismantling begins
	Behold the delicate engineering that makes up the Chronometric speedo work. A Chronometer is an instrument for the accurate measurement of time. The speedo combines a time movement, like a clock, and a distance movement. Chronometric is the	Most problems arise from over oiling / greasing of the drive cable which works its way into the instrument and prevents proper movement of the parts. The grease can be clearly seen here
		The chronometric movement removed. The assembly on the right is the odometer.
Other than the grease contamination my problem was a slightly bent sprung blade (arrowed) which was not engaging with its matching gear wheel. A slight adjustment sorted it out and after re-assembly it all worked perfectly.	The component parts ready for assembling. The casing was de-rusted and then put through my home Zinc plating system being given a yellow passivated finish. The inside was sprayed white. The new speedo face came via Ebay as did the trip meter adjuster. New glass face and the seals came from the internet.	Fitted back into the nacelle
The odometer was reset to zero and after 150 miles on the clock it has worked faultlessly