Matchless 450cc ?

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mdt-son
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Re: Matchless 450cc ?

Post by mdt-son »

410cc is obtained by using a 74mm piston off the M16S/G3S engine (1962-63) together with a standard 93mm stroke crankshaft. The G3S had integral pushrod tunnels and a through-stud design, thus the barrel may not fit a 1949 crankcase. I believe the 350 iron barrel would be at its limit if bored to 74mm.

The OPs engine seems to be a 16M crankcase with M16/G3 flywheels (1964-66) which provided a 85.5mm stroke. I don't understand the measurement of 82.22mm - maybe the OP meant 82.52mm ? In which case a pre-64 barrel, piston and head off a G80 (500cc) appears to have been fitted. Without shortening the barrel 7.5mm, the engine will hardly run.

See also the tech article in Jampot, Dec 2010.

-Knut
Stan Palmer
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Re: Matchless 450cc ?

Post by Stan Palmer »

That's a good article Rob. And great knowledge from MDT. It doesn't reveal what really happened to that engine. Maybe it will never be completely clear.
I have two 350 barrels that have been shortened. PO thought it was because somebody wanted to build an ohv V-twin on an unknown crankcase. I think I will dig them out and check if there are any other changes. Unless we are snowed in tomorrow.
Stan
G15 Roy
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Re: Matchless 450cc ?

Post by G15 Roy »

Rob Harknett wrote:
Chazzyb wrote:I'm sure I read of a mod in the dim and distant using a Triumph piston to do this. May not have been that capacity; 410 springs to mind.
I seem to recall a member who sold parts to make 410 cc comp engine at Jampot rallies Stan.
I think that was Steve Jones with one of his custom cast barrels and a Norton Piston.
Roy
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Eamonn
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Re: Matchless 450cc ?

Post by Eamonn »

Some photos that may help....
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Corners like a Lego man
BSA
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Re: Matchless 450cc ?

Post by BSA »

My apologies, I believe that I have been the unwitting cause of much unfounded speculation. The bike in question was bought by a friend of mine off eBay and delivered to me to hold onto for the time being. The seller was unsure as to the capacity so I removed the head and took some very rough measurements for him to get into a ball park. These very rough measurements have now taken on an accuracy that was never intended. Revisiting the stroke it would seem that it is a standard 93mm one for a Matchless.

Case are stamped 49/16M 11006 so I assume they are 1949 350 cases. We know nothing about the bike other than I think it came from the Gosport area. It seems to have been well cared for and although road registered in the early 2000's sits on racing tyres.

I shall post a few more photos when I've worked out how to do so.
BSA
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Re: Matchless 450cc ?

Post by BSA »

Some more 'photos. If anyone knows anything of this bike we would be intrigued to know.

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