timing side axle replacement

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Chris Berry
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Posts: 83
Joined: Fri Sep 16, 2016 7:51 am
Location: QUEENSLAND AUSTRALIA

timing side axle replacement

Post by Chris Berry »

Hi all, I am replacing the timing side axle on my 51 G80 engine. I am replacing the old single start axle with a 2 start axle. Do I need to replace the oil pump plunger also. All the pictures I have seen show a similar worm drive on all the oil pumps.

Thanks in advance
SPRIDDLER
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Joined: Wed Sep 01, 2004 1:00 am
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Re: timing side axle replacement

Post by SPRIDDLER »

From a search in the 'Tech. articles' on this site:
http://www.jampot.com/article_read.asp?id=333
One two start zoom (640x267).jpg
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Chris Berry
Member
Posts: 83
Joined: Fri Sep 16, 2016 7:51 am
Location: QUEENSLAND AUSTRALIA

Re: timing side axle replacement

Post by Chris Berry »

SPRIDDLER wrote:From a search in the 'Tech. articles' on this site:
http://www.jampot.com/article_read.asp?id=333
One two start zoom (640x267).jpg
Thanks spriddler. Does this mean that I cannot change the axle. I do not have the axle with me to measure as it is around 200 Miles away at a repair shop but by what I'm reading from the tech specs is the the two types of axle are different diameters (1/4") and therefore the bushing in the cranks case would also be different. Would you agree? The quandary I have here in Australia is that the bike has been in pieces for around 4 months after the crank pin broke and nothing is going right. I could possibly get a new single start axle but not a pump to match but can get a 2 start pump and axle from another source
SPRIDDLER
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Posts: 8542
Joined: Wed Sep 01, 2004 1:00 am
Location: WEST SUSSEX UK

Re: timing side axle replacement

Post by SPRIDDLER »

I daren't rely on my memory, Chris, but since the two start axle is a larger diameter (over its entire length) than the single start it won't fit your 'single start' flywheel. I assume you have the f/wheels with you so you need to get the distant workshop to measure the dia. of the two start axle.
I realise that you can't just pick up the right bits from an autojumble as we might over here and the assembly is expensive to ship from U.K. but maybe Steven at AMC Classic spares can help with s/h parts. I assume you'll also have to fit a matching timing side bush if you fit the larger two start axle.
Otherwise it may be possible for an engineer to open up the f/wheel to accept the larger two start axle. I really don't know if that is a practical step though.
'There is a tide in the affairs of men
Which taken at the flood............'
Chris Berry
Member
Posts: 83
Joined: Fri Sep 16, 2016 7:51 am
Location: QUEENSLAND AUSTRALIA

Re: timing side axle replacement

Post by Chris Berry »

SPRIDDLER wrote:I daren't rely on my memory, Chris, but since the two start axle is a larger diameter (over its entire length) than the single start it won't fit your 'single start' flywheel. I assume you have the f/wheels with you so you need to get the distant workshop to measure the dia. of the two start axle.
I realise that you can't just pick up the right bits from an autojumble as we might over here and the assembly is expensive to ship from U.K. but maybe Steven at AMC Classic spares can help with s/h parts. I assume you'll also have to fit a matching timing side bush if you fit the larger two start axle.
Otherwise it may be possible for an engineer to open up the f/wheel to accept the larger two start axle. I really don't know if that is a practical step though.
Unfortunately the flywheels are up with the axles however you may have hit on something there. I'm sure the guy doing the repair would have a flywheel up there suited to the axle as he has a whole shed full of British bike bits I would also be sure that the he would have a crankcase if needed so perhaps in there is the solution. Not that AMOC is anything to go by but when I compare the pictures of the two on their site (000760 and 015781) in relation to the timing gear spigot and the flywheel stud they look almost the same thinking perhaps they were all standardised at some time. .Time will tell when I get to do some measurements
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