1949 model 18 rear wheel spacers

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Invicta
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Re: 1949 model 18 rear wheel spacers

Post by Invicta »

Hi Clive,
Thank you very much for posting the pictures, as they say a picture paints a thousand words. The spacer, 41G3LH265 is on the inside of the speedo gear box, its job is to prevent the gear box being crushed and to lock it in position when the spindle nuts are tightened.
I can now set to work and shift the boss back down the shaft to where it should be now I can see how it should look. I have yet to acquire a speedo gear box for the bike as one was not in the box of bits. There are several on e bay , but I need to know what size the hole in it should be. I took the one off my 1950 model 18 and that has a 1/2" diameter hole in an inbuilt boss in the speedo gearbox. negating the need for the spacer 41G3LH265. So that one did not help me any. Thank you once again for all your help. David.
Mick D
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Re: 1949 model 18 rear wheel spacers

Post by Mick D »

Hi Clive

That assembly has to be wrong - no self respecting engineer would design a spindle in a fork to be retained solely by torque, there must be a way to eliminate the gaps as the spacer on the other end does. Do any of the available parts have a diameter equal to the slot in the fork?

Regards Mick

Edited to add: The period manuals, (illustration 21), suggest that the fork on that side had a clearance fit for the spindle, if the fork is as per Clive's photo I'd make a bush to take up the slack.
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clive
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Re: 1949 model 18 rear wheel spacers

Post by clive »

I agree with you Mick. But i cannot find the part number and i don't think the frames were made with different sized slots but its possible the rear subframe for mine is later one. As i said earlier i think i had a home made bush in the 49 i used to own. Bit surprised when i realised there was not one in my current rigid.
clive
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Duncan
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Re: 1949 model 18 rear wheel spacers

Post by Duncan »

Hi Clive

You may have a later subframe and need this spindle: http://www.jampot-spares.com/store/come ... duct=21059 it is stepped to engage in the fork and centralise the spindle.
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clive
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Re: 1949 model 18 rear wheel spacers

Post by clive »

Spot on Duncan but being a tight wad I was thinking that i might have a spare of the 1948 part which goes the other end. I could turn this down so i had the external washer and the spacer in one piece. If not i will be ordering tonight!
clive
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clive
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Re: 1949 model 18 rear wheel spacers

Post by clive »

Well having usurped this thread it makes sense to continue because I think it might help David . Checking my rear loop shows that it has equal size slots and checking the parts list suggests the spindle changed to the one Duncan has referenced (with a built in spacer) in 48. My 48 rigid is a bitza and has probably got the later rear loop, but it also has the 47 smaller rear brake fitted and I think the earlier frames not only had the slot smaller on one side but may also be narrower. I found this out only because I undid the right hand side and realised the frame was springing outwards. Not and enormous amount perhaps 1/4 inch but I have never noticed this in 25+ years of use, certainly a number of punctures and replacement of tyres. I realise this is because my method of fixing the wheel in place is to lock up the right hand side then lock up the brake side whilst standing on the brake pedal to centre the brake plate, not noticing any movement. David could it be that the earlier WD type spindle (without inbuilt the spacer for the larger fork end) are a little shorter? this may be part of your problem if you have the later 48 on larger 7 inch brake plate as the spacers at that end are different.

On to my problem, well I am not worried about the fork end springing out a bit unless Mick advises me that engineering wise its a problem, the wheels seem to be in line ok when it is tightened. How to sort out the spacer issue? Well I have dug around the garage and found my spare brakeplate side spacer from the 47 rear brake part number 41-G3L-B54. My plan is to get a mate with a lathe to machine down the outer part so that it is only 3mm deep (the thickness of the current washer) I will then fit it from the outside in place of the washer and it will fully support the spindle in the slightly wider fork end slot. The diameter of this spacer is slightly less than the washer currently fitted but I don't really see this as an issue as the fork end has a raised flat above and below and the spacer will engage against this, the washer simply projects beyond it. Of course the washer was partially chromed but you will see from the photos that function exceeds appearance on this bike! If the engineers can see a fault in this plan please shout out. I had thought of fitting the reduced spacer inside the frame up against the spacer on the spindle because of the frame springing out but if I did that there would not be enough thread to properly tighten up the nut the other side of the fork end. And I have a spare similar spindle so don't really want to splash out on the 49 spindle.
IMG_0624.JPG
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clive
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Mick D
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Re: 1949 model 18 rear wheel spacers

Post by Mick D »

clive wrote: I am not worried about the fork end springing out a bit unless Mick advises me that engineering wise its a problem,
Hi Clive

I wouldn't worry about taking up the spring - my only concern would be the wheel alignment but if it's been OK for you for 25 years go for your solution.

It's a shame your spindle isn't a little longer, then you could have thinned the spacer down to take up the spring and fitted it between the existing spacer and the fork, retaining the washer under the nut on the outside of the fork.

Regards Mick
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clive
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Re: 1949 model 18 rear wheel spacers

Post by clive »

Thanks for the advice on the fork springiness Mick.
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clive
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Re: 1949 model 18 rear wheel spacers

Post by clive »

well a bit of machining and the spindle is securely fixed from the outside. Not yet taken the bike out the flurries of snow are a bit off putting.
20210207_135127.jpg
So now I am now longer hijacking the thread I wondered how David is doing
Invicta wrote: I have yet to acquire a speedo gear box for the bike as one was not in the box of bits. There are several on e bay , but I need to know what size the hole in it should be. I took the one off my 1950 model 18 and that has a 1/2" diameter hole in an inbuilt boss in the speedo gearbox. negating the need for the spacer 41G3LH265. So that one did not help me any. Thank you once again for all your help. David.
The hole in the correct speedo drivebox is just large enough for the spindle to pass through and as you say trapped by spacers either side. I would stop using the 1950 model 18 for comparison as the spindle is 1/2 inch instead of the 7/16 inch on the 49 and all the spacers are different. How about your spindle, were you able to move the spacer along the shaft? Even if you have you are still going to need some sort of spacer along the lines of what I have fitted or buy the correct 49 spindle from the club that Duncan has referenced earlier. I take it that you do have the 49 rear brake (7 inch) and not the earlier smaller one.
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clive
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Mick D
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Re: 1949 model 18 rear wheel spacers

Post by Mick D »

Hi Clive

You must have a small clearance between your new modified spacer and the original one when all is clamped up, it's not obvious from the photo that you have one. If you don't have a clearance it indicates that the two spacers are clamping up on each other and consequently not the swinging arm fork.

As long as there's a clearance you're OK - if not I'd suggest you pare down the length of the spacer a little more before the snow lifts ;)

Regards Mick
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