Change back from 500 to 350?

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
SPRIDDLER
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Re: Change back from 500 to 350?

Post by SPRIDDLER »

Boycey wrote: I have dated the bike from the engine number and the lucas parts which are all 1954, the V5 has it first registered in 1955 though and it would appear it was an AFS bike in it's early days although it is currently painted black.
Just for interest……….
It may not be the original engine even if the V5 bears the current engine number. The i.d. of the bike (year, marque) is only and always determined (for ever) by the frame number, regardless of changes to any other parts.
If it still has its original or AFS reg'n number there's a website with much detail about the history of AFS bikes and another with lists of their reg'n numbers although I can't find the links at the mo. (EDIT) Ah, I see Dave's post has crossed with mine where he has given one of the sources.
There are original factory records available for civvy bikes and perhaps AFS bikes which can be obtained by using the club's Dating Service. See here:
http://www.jampot.com/Dating.asp

Nice project!
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Boycey
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Re: Change back from 500 to 350?

Post by Boycey »

Yes it has an NYV prefix, I managed to find the original auction catalogue when it was sold by the government ministry or home office etc, Eamonn Townsend was very helpful. It has definitely got its original engine, I found another one on a site in the USA (Mecum Auctions Las Vegas) that sold which had a frame and engine number only a couple away from mine, so really pleased it is all original. When I discovered the AFS connection I was even more tempted to go back to a 350, but it does seem the conversion has been done very well and I am curious to find out how a 500 will perform. It has turned out to be a great lockdown project! Thank you all for your help thus far, no doubt there will be plenty more calls for help!
Dave Holmes
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Re: Change back from 500 to 350?

Post by Dave Holmes »

Above, Pharisee has said that the conversion from 350 to 500cc was easy to do, and many have done this. My G3LS has also been converted and I am very happy with it, but I would be keen to know what change was made to effect the increased capacity. Different crankshaft with a longer throw?
NaughtyNetley
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Re: Change back from 500 to 350?

Post by NaughtyNetley »

Mine was already done when I bought it. A friend who's had a couple of these says different barrel and piston increases the cubic capacity. I have the 350 bits as well should I want to change.
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Pharisee
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Re: Change back from 500 to 350?

Post by Pharisee »

Dave Holmes wrote:Above, Pharisee has said that the conversion from 350 to 500cc was easy to do, and many have done this. My G3LS has also been converted and I am very happy with it, but I would be keen to know what change was made to effect the increased capacity. Different crankshaft with a longer throw?
Swap the barrel, piston and cylinder head. The stroke remains the same but the 350 crankshaft is balanced for the 350 piston so it would be best to get the crankshaft re-balanced with the 500cc piston.
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