primary chain gearbox adjuster

Information relating to the Matchless G11 or AJS Model 30 600cc twin
g5wqian
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primary chain gearbox adjuster

Post by g5wqian »

Hi all,
I have a 56 model 30 with burman box and tinplate primary chain cover .
I have adjusted the chain tension but I had no adjuster fitted to the bike , it was like that when ibought it a few years ago.
I just have a stud and nuts either side at present but now have a bunch of adjuster parts sorted to use on the bike.
What I would like to know please is how the adjuster is set out on the mounting plates and if it requires an adjuster thread and block on each side where the stud passes through on the top gearbox fixing.
I am unsure if there is only one adjuster on one side or if I need 2 ,ie one on primary side and one on kickstart side.
The manuals don't show the actual layout of all the pieces and I don't have access to another bike to compare mine to .
Pics would be very helpful if possible .
Thanks
Ian
JimFitz
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Re: primary chain gearbox adjuster

Post by JimFitz »

I seem to remember that two adjusters were only fitted on competition models.

Jim
Too old to Rock and Roll but too young to die.

1952 G80 rigid, 1960 G12 DL / Watsonian Monza, 1954 G80S.
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Duncan
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Re: primary chain gearbox adjuster

Post by Duncan »

Ian, hopefully the picture explains all:
Gearbox Adjuster.PNG
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Rob Harknett
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Re: primary chain gearbox adjuster

Post by Rob Harknett »

The adjustment was much the same from the prewar years onwards. So you can look in any year to complete the picture.
Don't forget the slacken the rear wheel nut and let off rear chain adjusters a bit. Adjust the primary chain first and tighten up. Then adjust rear chain.
Pic also here of the gear box side showing the arrangement also the adjuster parts.
Ashampoo_Snap_2017.01.14_13h20m53s_003_.png
Ashampoo_Snap_2017.01.14_13h17m32s_002_.png
Ashampoo_Snap_2017.01.14_13h13m30s_001_.png
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Duncan
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Re: primary chain gearbox adjuster

Post by Duncan »

Rob, I think you are mixing your "CP's" with your "B52's", 1956=B52, your first two pictures are of the CP arrangement.
g5wqian
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Re: primary chain gearbox adjuster

Post by g5wqian »

thanks very much .
i can see from the photo and diagram that rob put up now how i can fit the parts so in future i wont have to pry the gearbox back and forth to tension the primary chain up .

thanks for the info .

all the best
ian
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Rob Harknett
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Re: primary chain gearbox adjuster

Post by Rob Harknett »

Yes it was the adjuster parts and assembly of, plus pictures that you wanted Ian. As Duncan pointed out the gearboxes are different. I did mention and showed pictures can be found in other years. The parts do differ a little. But should had given you an idea of assembled adjuster parts. I have attached a fuzzy picture of my 1955 adjuster, the front threaded eye bolt slightly different from the 40's bike pic with CP box. You may still have to pry the gearbox a bit to loosen it off, muck on the studs, maybe a bit bent, stuck with paint etc
SDC14604.JPG
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g80csp11
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Re: primary chain gearbox adjuster

Post by g80csp11 »

Rob , must get down to specsavers my old glasses have gone out of adjustment
ajsph
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Re: primary chain gearbox adjuster

Post by ajsph »

56 gearbox adjusting parts were a one year solution, new frame new engine plates, but still using Burman gearbox, the spacer between eyebolt and engine plate is not shown in the spare list, but you need it. The user manual shows another solution but I have never seen this used with Burman gearboxes.
Best regards Poul
DSC00985_1.jpg
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g5wqian
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Re: primary chain gearbox adjuster

Post by g5wqian »

thanks for that poul and all , all the ideas are what i needed and i can get things organised now thanks .


i have had a look at mine , i can make up something suitable and have all the parts you show in the right of photo except for the spacer but i can make a spacer easily on the lathe .
i measured the required length of stud to go through the lot and it looks like it needs to be about 6" or so long if it has a nut and thread at each end .
the stud in there at present is barely long enough to take a nut each end so i need to do something anyway

i have 26tpi taps and dies so can make something i think .

i am going to scour the spares scheme parts and see what bits they have first as i may buy some new parts as well .

i guess the spacer sits on the outside to bring the adjuster threaded eye bolt parallel .

cheers .

ian
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