The gearbox on my December 1972 750 Commando has no serial number on the top? On the underside on 2 of the cases are the numbers 689 or 986 depending on which way up you read it. There are no signs of a number being ground off and the box looks entirely appropriate for the age of the bike. I wondered if the warranty replacement boxes had no number? Gearbox works absolutely fine just a little puzzled by the lack of a number. Any advice would be welcome. Thanks Paul.
If the two 689 numbers are…
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Thanks Karl, the numbers a…
Thanks Karl,
the numbers appear if memory serves me right on the underside of inner and clutch side cases of the gearbox. I see what you mean that it might indicate matching cases like on the crank cases. I've seen crank cases without numbers but not gearboxes. Paul.
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Previously paul_dudill wro…
Previously paul_dudill wrote:
Just to be clear, My 72 Commando has number stamped on top mounting lug rather then usual place on case for earlier models, you have looked there too?
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Thanks Martin, I had check…
Thanks Martin,
I had checked there but couldn't see anything. I have now pulled the bike out into the daylight and low and behold the final 2 numbers are visible. These correspond with the final 2 numbers on the engine and frame. There appears to be a further very faint 3 digit number with a letter P I think. Did they stamp a shop and P for Plumstead on them, I thought they just stamped the gearbox with the engine number digits? The first numbers look like they've been worn away by breather/oil pipes rubbing against the lug over the years. Paul.
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If the two 689 numbers are on the crankcase halves this was a practice done in the manufacturing by Norton. It was to identify that those are a matching pair and machined together.