Author Topic: Erratic chronometric  (Read 387 times)

Offline Oggers

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Erratic chronometric
« on: March 25, 2022, 04:54:06 PM »
Gents

Smith chronometric speedo on a 55 Velocette MSS has developed a fault. Basically it is reading very low - reads 10 mph when shoud be 40 or so. Mileometer works, cable looks OK, no sharp turns or kinks in the cable. Fine yesterday!

Clues appreciated.

Thanks as always

Mark

Offline R

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Re: Erratic chronometric
« Reply #1 on: March 25, 2022, 09:27:06 PM »
Are you intending to diy, or take it to a specialist ?

Offline Oggers

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Re: Erratic chronometric
« Reply #2 on: March 28, 2022, 08:14:04 AM »
A few drops of wd40 seems to have sorted it....I like simple solutions.

Offline Rex

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Re: Erratic chronometric
« Reply #3 on: March 28, 2022, 11:15:40 AM »
From what I've experienced and read over the years, the grease used on assembly goes hard and stops the finely-tuned mechanism from incrementing and returning. Presumably the WD40 softens the hard grease enough to allow it to work as it should.
 Whatever solvent is used never ever get it on the drums or face as the numerals smudge and fade very easily.

Offline iansoady

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Re: Erratic chronometric
« Reply #4 on: March 28, 2022, 11:53:41 AM »
s the numerals smudge and fade very easily.

Yes, I can endorse this having ruined a trip drum many years ago.
Ian
1952 Norton ES2