Ive just finished restoring a 1948 M33 which was built from boxes of bits. The speedo I had (an S433M - which I presumed and still think was original), was sent off for full restoration and came back almost as new (lovely job). I also replaced the front wheel speedo drive gear unit and cable (bought on line). When I took the bike out for it’s first test ride yesterday, I noticed the speedo wasn’t working. Long story short, the cable is rotating in the wrong direction i.e. when looking at the back of the speedo, it’s rotating clockwise and the speedo doesn’t work. When I use a drill to drive the speedo cable in an anti clockwise direction, the speedo works perfectly. I am assuming that the new front wheel drive gear unit I bought is rotating in the wrong direction.

My question is can someone please remove their speedo cable from the speedo and looking in the direction of the back of the speedo, let me know if it’s turning clockwise or anti clockwise. This way I’ll know if my drive gear is wrong or if in fact the speedo I have is not original to my M33.

Any help will be very much appreciated.

Lindsay, if you jack your front wheel up and spin the wheel forward, the square that drives the cable should be going clockwise as you look down on it. The BSA speedo drive that fit the the left front hub are very hard to find. Nearly every one that you find will be for another bike that works off the rear right hub.....And of course will be the wrong rotation. Ron

email (option): ronpier@talk21.com

Thanks for that Ron. Yes, that’s exactly my problem, the square drive is turning anti-clockwise and as you say should clockwise. Is there a specific BSA part number I should be looking for?

Regards, Lindsay

The BSA part number is 29-5737 but I don't think that or the military or Smiths number will help much. Here is my spare NOS drive box (sorry not for sale) Sods law, the moment I sold it, one of mine will go wrong!!

I pick them up at jumbles whenever I see them and by turning the two drive dogs clockwise, the cable output should also turn clockwise....Invariably they are anti clock. It's a case of hoping someone here has one or jumbles where you can test yourself or ebay where you have to ask the seller to check the rotation.

email (option): ronpier@talk21.com

Thanks Ron, much appreciated.

To test one, hold the drive in the palm of your left hand with the 'open side' facing to your right and with the cable connection vertically upwards, turn the drive tangs inside the drive away from you with your right hand and the cable drive should move clockwise...Ian

email (option): ian@wright52.plus.com