650SS Clocks - Speedo and Tacho

What year is your 650SS? They started with Chronometric instruments, changing to Magnetics in 1964.

For that year, the speedo was SSM.3002/00; 2:1 drive. Rev-counter RSM.3003/00 8000rpm; 2:1 drive.

9000rpm & 10000rpm rev-counters were 4:1 drive.

However, yours may not be that year. 

A 10000rpm tacho will have a different number, for sure.

The 1966 spec; I don't have 1967 info; is as follows:

Speedo SSM3001/00A; 120mph speedo, black face, with trip mileage; 2:1 drive. This is more likely to be correct for your bike that the 1964 offering.

Tacho RSM3003/00A 8000rpm, black face. 2:1 drive.

This is fact, cross-referenced, as well as being the exact ones fitted to my bike; I have just looked to check!

A 10,000rpm tacho for that year would be RSM3003/01; 4:1 drive. I don't know why Norton would fit a 10,000rpm tacho...?

Whether they changed for 1967 I don't know. I have just checked 1965 spec, which confirms as being the same as 1966. As you see, the numbers changed slightly from 1964; the first year of magnetics; to 1965. Did they change again for 1967? I don't know.

As for the magazine article, the instruments they mention do not match Smith's own data, or others which I have cross-referenced, or my own.

Surprise surprise!

Ian

I have a late Atlas after67  (got to check) Will take a look.

Leonard. Yes, you need the 8000rpm one.

Here is a pic of the 1965/66 spec. clocks.

Light switch should be on the clock mounting plate btw, but I prefer it in the headlamp. Keeps all that wiring out of sight and the weather.

Ian

My Mercury is 1969 and has dark grey magnetic speedo and rev counter.  The speedo is 120mph,SSM-3001/00B (1600) and the tacho is a 10,000rpm RSM-3003/01A.

I cannot verify whether these are correct as the machine was re-imported from Canada and various "modifications" (or bodges) were carried out before I owned it.  I would have expected a 120mph speedo rather than 150mph, but perhaps the 650SS performance required the faster speedo!

My tacho works fine but the speedo reads lower than actual speed, so I'll now check the gearbox on the back wheel.

The tacho drive gearbox for the Mercury is BG1508/05 and is a 1:1 ratio, reversing type.

Philip

From the -68 650SS.

Metric version of the 120MPH one.Bezel on the speedo shows signs of that it has been opened. They did not manage to put the glass and sticker straight. The 8000 RPM RSM 3003/00A tacho seems untampered as seen in the picture.

Leonard. It may well be that in 1962 the 650SS was fitted with a 150mph speedo, but it is not relevant to our discussion, as they were Chronometric. As I said, Magnetics replaced Chronometrics on Nortons in 1964; most of them, anyway. The Police bikes continued with Chronometrics for some while after. I know the Model 99 had a 120mph speedo in 1962, with a slightly different spec. number to the 650, so that could explain it.

Yes, mine only has a toggle switch for the lights, but originality is not so vital for me, as I have a 1964 650SS engine in a 1955 Wideline frame, with late Atlas front end, early Commando tls front brake and mudguards etc..... all Norton, but spanning about 15 years!

As I said regarding the magazine article, have you never noticed mistakes and mis-information in Mortons Media comics before? They are riddled with them. Not a reliable source from which to shell out your hard-earned, without cross-referencing first. I would rather trust Smiths Instruments own data from the period, or Norton's own, if you could find it.

I am a little intrigued about the description of a dark grey face. I have a couple of 60mm grey-faced Magnetics on other machines, but they are a fairly light grey. I was not aware of the dark grey. Is the assumption that all Magnetics had these dark grey faces? Mine look black to me, but under glass, maybe not? Phil?

Quick edit - looking a Mikael's photo of his RSM.3003/00A tacho, the face does look dark grey. If mine is dark grey, it is a lot darker than that! Mine have been rebuilt at some stage, so maybe the interpretation of dark grey was a little flexible....

Cheers

Ian

When I look at my meters in different light, shade of grey differs much. My pics was taken in much light, so they appears to have a much lighter shade than they do outdoors on a cloudy day.

The grey faced speedo fitted to 650SS & Atlas was 120mph and did not has a trip metre.

Leonard. Logic, as you say, wasn't always followed. It was not Norton by then, it was AMC. Product standardisation would have come into play. They were almost on their uppers by 1965. The Magnetic speedos most certainly were 120mph items, including trip (Alan; you can see the trip in Mikael's and my photos!)), for most of their run; I can't speak after 1966 however.

If you have a pair of nice clocks which look period, unless you are after concours awards, I shouldn't worry too much. Having said that, Magnetics are way cheaper to have work done on than Chronometrics. You pays yer money etc.......

Ian

Have had a busy weekend so haven't been keeping up with these comments.  I've inspected my speedo and tacho and the main outer part of the face is very dark, more black than grey, but the inner centre of the dials are light grey.  The reflection on the glass makes it difficult to see the colours clearly.

When the Mercury was in production the standard machine only had a speedo, so any tacho was an extra or added later by a subsequent owner.  I agree with Ian, put on your period clocks and enjoy the machine.  A problem with Magnetics is that refitting the bezel as it needs a roller to gently turn it over the flange; a friend with a lathe helped me replace the broken glass.

Philip.