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ES2 gearbox shaft

Can anyone tell me the diameter of the gearbox main shaft where it sits in the clutch hub/slider.

On my ES2 the hub is loose on the shaft and I don't know which is correct.

I need an accurate measurement please, across the splines.

Mine measures 20.568mm

Thank you.

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All the laydown and amc boxes take the same clutch so the shafts will be the same size, the battery in my gauge says it’s too cold but reading the scale it also looks like a little under 21mm. Are you sure the play is in the spider and not the basket? It’s not unusual for that to move  when the clutch is tightly on the shaft - mine does anyway! 

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If  t'were mine ,I would get a new spider and if still a bit loose  install it with a little  nut lock  at each end  . If it has to be removed later  ,I would heat up to release the  nut lock. . Or copper plate the spider ,something you can do yourself .

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Does the clutch still move when the retaining nut is done up tight? If it is then it’s not the spider/shaft. The spider can’t move when boiled up tight against the shoulder.

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Yes, if the shaft size is the same as mine, the play is in the spider, it has a 'fall-on' fit now, it can be rocked and rotated (slightly) on the shaft.

The clutch has new rubbers and when the spider is tightened up on the shaft, there is no movement of the basket, so the slop cannot be in the basket.

As there is no movement in operation between shaft and spider, the inner splines could not have worn, so they must have been like this from the day it was purchased - not by me, the bike was last used in 1978.

The problem too is that some members have told me that some new spiders bought are not accurately made, and cannot really be used.

A further problem is that living in South Africa, a new spider will have to be imported, so I don't want to buy a bad one.

Can you recommend a supplier who will definitely supply an accurately made spider?

I must think about what to do, maybe some more measuring.

Thank you for your help.

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When pulled up tight, there is no relative movement between shaft and spider/hub.

The problem is that when the nut is pulled up tight, the spider is fixed out of line so there is a permanent offset which causes the chain to tighten and loosen.

Even if I use Lock nut, tightening the nut forces the alignment out of line so I have this offset. 

To electroplate the spider is an interesting idea - I have a kit to do zinc plating, I'll look into this.

Thank you.

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I think RGM had a problem with the quality of a batch of spiders a few years ago, but that has since been remedied. I have one fitted with no problems. Andover also sell them but it is much more expensive. Can’t be sure it’s because it’s a better quality but would hope so. 

I expect the shoulder in the spider has worn unevenly, I had one wear away completely. Sounds like a new one would be the best option.

Dan

 



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