Speedo rebuild

[rolesyboy]

Hi All. I have aquired pile of bits which includes a 120 S speedo. The back case is rusty and I do have a 'Super' type speedo ie 90mph which I would like to use for spares. Is rebuilding yourself realistic or is it an impossible job? I imagine it is fairly straightforward if done methodically and carefully but I would welcome any tips or advise on any parts that are not interchangable. The other question is can I retain the lions share of my 90mph speedo and just bolt on the S bits to make life easier? Thanks.

[abri]

Aren't there differences in the distribution of lights around the face between these two speedos?

Either way, I am very interested in this same topic because I have a 120mph speedo with a stuck odometer....and I also have a fairly new 90mph speedo from a late '64 Austin Mini 850. So I'm planning a similar operation. I would have thought one could try and swap the odometer bits around but I haven't taken it apart in a long time, so I'd have to check the details.

[nick rogers]

Don't canibalise a Super speedo! They are rarer than 120 ones. Use any other 90 speedo that was used with the same final drive as the S. This can be determined by the 4 digit revs per mile figure on the speedo face.

[rolesyboy]

Hi Nick. Thanks for your reply. Don't suppose you know what serial numbers I should look for. I don't have a clue. Is it based on the 4417/00 or 4417/18 figures? Cheers. Mark

PS If you don't reply within 24 hours the 'Super' speedo gets it.......

[nick rogers]

OK. OK. Put down that hammer ! The 3.76 final drive would have 1376 and the 3.4 would have 1280 as the RPM figures. The Super was 3.765 but it was on cross plies so would have 1408.
BTW, the Super speedo is rare because it's the only black 90 mph with only 5 digits on the odometer.
(unless anyone knows differently).