Smiths Chrono Speedo

Bazlerker

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Is a Smiths Chronometric SC1302/01 1476 compatible with a Vincent?... I can't see where the trip reset is located from the pics..
 

nkt267

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does it have an odometer AND mileage readout..If it only has the one there is no trip..John
 

Bazlerker

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It does have both an odometer and a speedometer..I think it's just the angle that the pic was taken from...
 

Magnetoman

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Is a Smiths Chronometric SC1302/01 1476 compatible with a Vincent?...
Forgive me if you already know the following. Chronometrics were made in configurations for clockwise and counter-clockwise rotation of the cable as viewed from the face of the unit. The SC1302/01 was used on a BSA so it requires that the cable turn clockwise. Unfortunately, I don't remember for sure which way a Vincent's unit turns and I don't want to make a mistake so someone else will have provide that information.

The 1476 is the number of turns/mile of the cable that the unit was originally calibrated for. Again, I don't remember the figure for a Vincent, but to the extent it differs from 1476 both the speed and distance will be incorrect. However, for modern purposes, typically this is irrelevant since nearly all Chronometrics were made with settings between ~1400 and 1600. "Modern" magnetic Smiths units tend to be 1000 turns/mile (a Chronometric on police Norton Commandos also used the 1000 figure).

As an example, if the Vincent should have a, say, 1600 turns/mile unit, and you install a 1476, the speedometer (and odometer) will read high by 1600/1476 = 8%. If this were the case, and if the unit says you're doing 65 mph you really are doing 60 mph. In practice, what this means is if the SC1302/01 speedometer has the correct rotation for a Vincent, and is in reasonable condition, it will be fine.
 

nkt267

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The speedo for a Vin should turn Anti clock looking from underneath the speedo..the drive for the gearbox on the wheel is clockwise in looking at the drive end and clockwise out looking down where the spade goes making it anticlock looking into the cable drive on the speedo..John
 

Magnetoman

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The speedo for a Vin should turn Anti clock looking from underneath the speedo...
So, clockwise when looking at the face, or when looking at the direction the inner cable turns if detached from the united and looked at end-on. The direction of rotation is the source of much confusion since often people write something like "clockwise" but don't clarify whether that's from the front or the back of the unit. I'm nearly certain Smiths' use of CW and CCW (or anti-CW) is from the point of view of looking at the face of the unit.

A reversible drill makes it easy to test if a speedometer is working reasonably correctly. Insert a short length of cable cut from an old one in the chuck. Since from the back of a CW speedometer unit the cable turns CCW, set the drill so it operates in reverse and insert the cable into the unit. If the drill turns at ~1500 rpm (check the manufacturers specs) the speedometer should read ~60 mph. This is because 60 mph is 1 mile/min., so 1500 revs/min of the cable will spin a speedometer calibrated for ~1400-1600 such that it reads ~60 mph. The odometer gearing is separate, but can be checked the same way. If the drill is operated for a minute the odometer should advance by ~1 mile (or, 1/4 mi. in a more reasonable 15-sec. test).
 

nkt267

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Ashampoo_Snap_2016.10.15_08h54m43s_001_.png

this is one of the photos the seller has posted. If it had a bottom trip it would come out roughly between the stud at 10 0clock and the drive cable input just a bit in from the edge. If it had a side trip it would come out of the side of the case in a similar positionpositionpositionposition
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P1010063 - Copy.JPG

The second 2 photos are of my spare for the Comet just to show what a side trip should look like and also what the face of any chronometric should look like that has any sort of trip..john
 
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