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1975 Mk3 Commando rear drive sprocket

Submitted by christopher_fe… on Sat, 12/11/2022
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Commando

Hi again everyone I have recently fitted new rear wheel bearings so thought I should do the drive sprocket as well and wish I had not bothered because every time I re-assemble something is binding, it feels like it is the speedo drive but cannot really be sure if I slacken the hub nut slightly everything is free, the new bearing is a sealed bearing so I have not replaced the seal and the bearing appears to be the same size, the speedo drive is perfectly free until nipped up can anyone suggest what I am doing wrong as it has me baffled, many thanks Chris

Submitted by martin_freeman on Sat, 12/11/2022

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Two things, firstly put the seal back in, worn out or not it may be acting as a spacer, secondly while reassembling check two tangs on inside of speedo drive are engaged in their slots and that they have not been crushed.

Good look spannering

martin

Submitted by richard_payne on Sat, 12/11/2022

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I have an idea that the drawing in the parts book isn't 100%. There should be a spacer inside the speedo drive, and a thick washer on the outside. Have you tried assembling without the wheel in place ?

Submitted by alan_sessions on Sat, 12/11/2022

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Parts book has oil seal item 25 in wrong place - it is the other side of the bearing. I have had the speedo nipping up when everything tightened - solution was a thin washer (I used a copper washer from the oil pressure relief valve) used as a spacer between spacer item 11 and bearing item 23.

Thanks for your advice with spacer which was also mentioned on another forum it appears to have worked I will not know for sure until it comes out of hibernation

 


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