Swap Tim Primary for All-Alloy Cases?

Information relating to the Matchless G9 or AJS Model 20 500cc twin
g5wqian
Member
Posts: 220
Joined: Wed Nov 18, 2015 7:43 am
Location: wiltshire
Location: near swindon wilts

Re: Swap Tim Primary for All-Alloy Cases?

Post by g5wqian »

i know i cant answer the question exactly but i have an alternator crank in my 56 ajs model 30 and it also has a tin primary chain case .

the alternator crank has a long snout and it fits inside my tin chaincase , i think you are trying to go the other way round but using a short snout dynamo crank ? .

alloy cases were fitted in 1957 along same time as the rear shocks and frame lugs were changed from jampot shock rear ends , i dont know much about the alloy cases so i dont know if there were 2 types , one for dynamo and one for alternators with bigger "bumps" , ie you may need to find a bigger "bump" type so you can fit the cushdrive /dynamo crank stuff in it . ...

i do not have a cushdrive on the crank , its got a spacer lockwasher and sprocket , with a nut on it but not a breather nut .

you can if you take your time , utilise an old rotor from an alternator and remove the steel centre from it and this will be the "spacer" and then use the breather nut etc that goes with the rotor fitment .

i have a 24 tooth engine sprocket with this .

gearbox is a burman GB .

i did think about putting alloy cases on but decided to keep the tin one as i was able to seal it just fine using the clubs modified primary chain case seal and no sealant and its easy to get the tin case off .

i have a breather pipe boss welded to the rear rocker cover with bsp elbow screwed into it and use a mk1 mini clutch breather modified , the breather is jubilee clipped up under the frame tube under the fuel tank, with a 10mm id rubber hose between breather and rocker cover .

hopefully you can get sorted someway of other .

will be good to know how you get on with it .
ian
peterg123
Posts: 44
Joined: Wed Nov 10, 2021 7:36 am
Location: Norway NORWAY

Re: Swap Tim Primary for All-Alloy Cases?

Post by peterg123 »

Thank you Ian for this. I have some tin cases n good condition but glad to hear the club has an improved seal that works. In that case I won't need to bother with alloy modifications.
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