Author Topic: MKIII Speedo  (Read 2476 times)

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Offline Killipso

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MKIII Speedo
« on: 15 Jul 2012 at 08:47 »
Before I go dismantling the speedo I wanted to know a little about it. There's an electrical cable goes in the back - it seems to be sprung-loaded - I'm worried this and several other parts may pop loose when I open the shell....

Any info would be helpful. No detail to be found in the standard manual and J Holme's guide.

Raif

Offline Dawn

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Re: MKIII Speedo
« Reply #1 on: 15 Jul 2012 at 17:15 »
Speedo's can be a very tricky part to play with, I say that as my Father took one apart & it stayed apart....

In doing the bike shows I have discovered a geniuine nice chap who repairs speedo's & will only do what you ask, he will also sell you a part if he has it.  Best of all he is near to us based in Nottingham.  Details below:-

Russell P Smalley
25 Gladehill Road
Nottingham
Nottinghamshire
NG5 5SA

info@chronometrics.co.uk

This man is not the one who does all shows & charges a small fortune (he tends to stay in the local area).

Offline eddie

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Re: MKIII Speedo
« Reply #2 on: 15 Jul 2012 at 20:08 »
Raif,
      The spring loaded bit that the wire goes into is the holder for the speedo bulb. If you undo the knurled ring, the holder complete with the bulb can be withdrawn. To attempt any other work on the speedo, you will need to remove the rim and glass - then remove the 2 cheesehead screws from the underside of the speedo head ( if your speedo has a trip mileage, you will also have to remove the trip knob). Having done this, the works can be withdrawn from the case (it may be a bit stubborn as the paper gasket sometimes sticks it to the case). With the works removed, you will probably be horrified at it's complexity, but don't be put off. The whole mechanism is akin to a clock (with a balance wheel and all sorts of levers). Most problems with chronometrics that have been idle for some time can be attributed to the oil/grease having dried up or become very sticky. A spray of WD40 and a careful clean out usually results in the unit working again. A chronometric speedo is totally mechanical and either works or it doesn't - it will not give a false reading (either high or low), unlike later magnetic units that can be affected by the distance between the magnet and the reacting disc, or the drag on the needle.
   Hope this is of some help,
       Regards,
                  Eddie.

Offline Killipso

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Re: MKIII Speedo
« Reply #3 on: 15 Jul 2012 at 20:18 »
Thanks Dawn, I really appreciate those contact details. And thanks Eddie too, I believe the unit is sound and probably just needs the kind of 'refresh' you speak of.

With both your replies I have it covered now :-)

Thanks again,
Raif