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Laydown gearbox mainshaft Shims?

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Laydown gearbox mainshaft Shims?

Posted by david_veevers at August 14. 2017

As per the title really, I'm looking for part number 78 on the below diagram.

https://andover-norton.co.uk/img/imagescaler/89/89e80e095351d9495891f11165664ce2.jpg

I've changed the brass bush (11) and I still have almost 1/8" of float on the mainshaft. Can anyone recommend anywhere to get some? The closest I could get was some 16mmX22mm shims, I think the originals are 5/8" x 1 1/4" as I have 1 shim in the box already.

 

I've already tried Mick Hemmings, Mike Pemberton, Andover and RGM and can't source any originals.

 

The root problem I'm trying to solve is a clutch drag issue and reducing this end float is pretty much the last thing I have to try.

 

Regards,

 

David

Re: Laydown gearbox mainshaft Shims?

Posted by Barry Carson at August 15. 2017

Re: Laydown gearbox mainshaft Shims?

Posted by Paul Knapp at August 15. 2017

Hi David, it's a while since I had my laydown box opened, but isn't No. 78 an oil slinger for the main shaft open bearing? My laydown box had an alarming amount of end float on the bench, but when fitted and the clutch push rod is correctly adjusted, the end float is taken up. The push rod stops the clutch from drifting towards the box when adjusted. Have you measured the end float accurately, as it is generally a lot less than estimated.   

Re: Laydown gearbox mainshaft Shims?

Posted by Charles Bovington at August 15. 2017

Previously Paul Knapp wrote:

Hi David, it's a while since I had my laydown box opened, but isn't No. 78 an oil slinger for the main shaft open bearing? My laydown box had an alarming amount of end float on the bench, but when fitted and the clutch push rod is correctly adjusted, the end float is taken up. The push rod stops the clutch from drifting towards the box when adjusted. Have you measured the end float accurately, as it is generally a lot less than estimated.   

I think you are mixing up the flinger /oil seal part 16 in this diagram with part 78. 0.005 to 0.010 " is recommended, I believe. For the AMC box the various thickness rear isolastic shims for the commando are suitable. Not sure of suitability for the laydown.
 

Re: Laydown gearbox mainshaft Shims?

Posted by david_veevers at August 15. 2017

@Charles - I've relatively recently rebuilt an AMC box and used the same isolastic shims, I think I used them for the layshaft on the AMC though. I had a load left and so started on my Laydown box thinking I could use the same ones but they're too large for the Main shaft in the laydown box.

@Ian - I'll try them, not holding out much hope.

@Barry - That looks more like part 16 isn't it? the ID looks correct, but the OD seems way to large.

When the box is together and clutch on there is at least 2mm of end float on all of it. I measured it with a dial guage.

It makes adjusting the clutch very hard as I need to take up all this slop first, if I don't I've got drastically reduced clutch movement as pulling the lever moves the whole lot before expanding the clutch. I've been getting horrible clutch drag, to the point where I can't use the bike really as the clutch binds up over even short periods of having it in.

Re: Laydown gearbox mainshaft Shims?

Posted by Paul Knapp at August 15. 2017

To reduce all that slop, loosen the pinch bolt on the worm actuating arm (Under cover plate R/H side of box) then with a screw driver, turn the worm clockwise till there is virtually no play on the rod,(leave the tiniest amount) then holding this position, pull downwards the arm that the cable end is attached to as far as it will swing, then tighten pinch bolt.

Re: Laydown gearbox mainshaft Shims?

Posted by Barry Carson at August 15. 2017

Re: Laydown gearbox mainshaft Shims?

Posted by david_veevers at August 16. 2017

Hmm yeah, looks right. From the description of the below one though, and the specified size I don't think it's the right one still. It says it goes into the case before the bearing is fitted. In the Mick hemming video and the parts diagram it goes onto the main shaft after the bearing is fitted.

To fit that shim I'd need to remove the bearing.

 

There was one in there when I took it apart, and it may not be the correct part, but it's definately 5/8 ID, 1 1/4 OD. It was around 0.4mm thick, or 0.015".

 

 

https://www.rgmnorton.co.uk/buy/mainshaft-bearing-packing-washer_602.htm?sid=1310720

 

 

I'll see how the 16mm x 22mm ones fit once they arrive, I don't really want it running against both races of the bearing and the one above will.

Re: Laydown gearbox mainshaft Shims?

Posted by richard_payne at August 16. 2017

'Packing Washer' seems the wrong name to me; Isn't it the 'pen steel' oil retaining plate ? It actually sits in a recess behind the bearing so doesn't have a shim function...and they do often pick-up and spin.

Late model Doll's Heads and upright boxes have a 'dished steel washer' fitted between mainshaft 1st and the bearing in the inner cover. The amount of movement that you have might be best dealt with in that way.

It may be something that you've looked at but the clutch operating worm on these boxes is quite 'slow' and won't lift if the handlebar levers are pattern types with only 7/8" between pivot and nipple centre. I believe that they are usually 1 1/16" or 1 1/8" on some models.

Re: Laydown gearbox mainshaft Shims?

Posted by John Hawden at August 23. 2017

Previously richard_payne wrote:

'Packing Washer' seems the wrong name to me; Isn't it the 'pen steel' oil retaining plate ? It actually sits in a recess behind the bearing so doesn't have a shim function...and they do often pick-up and spin.

Late model Doll's Heads and upright boxes have a 'dished steel washer' fitted between mainshaft 1st and the bearing in the inner cover. The amount of movement that you have might be best dealt with in that way.

It may be something that you've looked at but the clutch operating worm on these boxes is quite 'slow' and won't lift if the handlebar levers are pattern types with only 7/8" between pivot and nipple centre. I believe that they are usually 1 1/16" or 1 1/8" on some models.

Re: Laydown gearbox mainshaft Shims?

Posted by John Hawden at August 23. 2017

Richard has `hit the nail on the head` with his comment. Until I obtain correct levers, I have had to fit pattern levers on both my renovated ES2 and my 19S. Pivots are wrong on the levers and I have had to take quite a drastic action of cutting, bending and rewelding the clutch levers so that I can actually use the clutch. Both bikes now work well....but the levers look dreadful.

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