Speedometer cable

Merlin · Post by **Merlin** » Sat Jul 31, 2004 10:09 pm

Hi,Can you help today the whole of my speedo cable finished up around my rear wheel spindle it having been ripped out of the head and frame holding straps.It looks as tho the gear box on the rear wheel has unwound itself(if thats what you would call it)The bike in question 1956 G3LS. Many thanks any help much appreciated Stuart[:(]

Biscuit · Post by **Biscuit** » Sun Aug 01, 2004 10:04 am

Have you removed the rear wheel recently, if so did you replace, tightening the nuts in the correct sequence?. This problem can occur if the gearbox drive lugs are not engaged with the corresponding slots in the hub. See reply on 'Help' forum, page three, 19th. May last 'Rear hub and speedo drive'

Colin F · Post by **Colin F** » Sun Aug 01, 2004 6:50 pm

The other common cause of this is faulty reassembly of the seals and spacers in the rear wheel. There is one spacer that is shown on some drawings the wrong way round! It should act as a spacer for the oil seal, not as an oil seal holder!

Biscuit · Post by **Biscuit** » Sun Aug 01, 2004 6:55 pm

Unless, of course, it is the felt type seal, admittably not on this model though!.

Merlin · Post by **Merlin** » Sun Aug 01, 2004 9:05 pm

Thank you all for your help I have not removed the rear wheel since rebuild by a n other some 98 miles ago apart from the obvious new cable will I need a new gear box drive or can I simple remove and rebuild? Many thanks
Stuart[:D]

Biscuit · Post by **Biscuit** » Mon Aug 02, 2004 11:39 am

Hi Stuart, not knowing your knowledge or expertise, if the following seems patronising or simplistic, please forgive me. Remove the speedo gearbox, inside you will see two diametrically opposed drive dogs, check these are undamaged. These dogs are part of rhe drive gear. Turn the gear by means of the dogs, what resistance there is should be uniform through three or four revolutions, repeat the exercise looking at the square recess housing the speedo cable, ensuring that it turns, it helps to insert a small screwdiver in the recess to give some resistance to ensure that the gears are not slipping. Before reassembling it would be wise to check the assembly of the oil seal assembly as indicated by Colin. Slacken the locking ring on the bearing adjusting sleeve, remove the sleeve, remove, hopefully in this order - plain washer, oil seal, dished cup and spacer. replace in the reverse order. The spacer floats about a bit but is held in place by the cup or oil seal, can't remember which. When replacing the bearing adjusting sleeve, if the bearing adjustment is correct, just nip the sleeve against the bearing outer and tighten the locking ring. Follow the instructions previously referred elswhere in the 'Help' Forum. Note - if the rear wheel stiffens up when tightening the thin nut holding the speedo gearbox, then the dive dogs are not engaged with the adjusting sleeve slots, and the problem will reoccur. When buying a new speedo cable, get one from somebody who knows the difference between the chronometric speedo and the later magnetic thing ie. get it from the Club. Either way, when inserting the cable at the speedo end, ensure that the outer cable collar abuts against the end of the thread, if not the inner cable forces the speedo drive worm against it's locating 'finger' plate resulting in broken fingers. the speedo then stays at whatever speed was indicated when the plate broke.

Merlin · Post by **Merlin** » Mon Aug 02, 2004 1:10 pm

Thank you for that Alan will try over next week or so.It is a long time since I did any work on thing mechanical so the more instruction the better.[:o)]

Merlin · Post by **Merlin** » Thu Aug 19, 2004 11:28 am

Hi
Could someone please tell me if speedo cable part number 900071/5 is suitable for my 1956 G3LS chronometric unit(Smiths)Spares have plenty but could not be sure.[:D]