Which sub model is this 1973 Commando

marshg246 said:

Do you know if any bikes after 212278 were actually built using the RH1 head?

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No I don't. Possibly Hi-Rider.

marshg246 said:

I assume it was just there to provide info on replacements for bikes that used it.

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But then it would be in the previous parts books not 212278, actually of course it is in the earlier parts books.

Gear box matches tag and engine .
212352 with a trailing S

Daytonachuff said:

Gear box matches tag and engine .
212352 with a trailing S

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What is the trailing letter represent? Mine has an "L".

TJBaker57 said:

What is the trailing letter represent? Mine has an "L".

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It generally means nothing outside the factory.

L.A.B. said:

It generally means nothing outside the factory.

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I was just reading through old posts and discovered your earlier posts on the subject. Wondering if anyone has compiled any sort of listing that might allow speculation about what factory change prompted what letter.

Daytonachuff said:

Gear box matches tag and engine .
212352 with a trailing S

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For what it's worth, my 750 Roadster, built in the same month as yours (Oct. 72) also has the "S" stamped after the serial number on top of the gearbox.

LPCityNorton said:

For what it's worth, my 750 Roadster, built in the same month as yours (Oct. 72) also has the "S" stamped after the serial number on top of the gearbox.

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Just a guess, but I'm assuming a batch indicator - maybe from the foundry or machine shop that took them from a raw casting to a machined gearbox shell.

I'm working on one right now in the same range that has a "W" and it was clearly stamped at a different time from the serial number. Many have no letter. There are numbers all over the bikes that have no useful meaning outside the factory, and most are not consistently there.

Two I'm trying to figure out are the 001xx number stamped into the drive side of the headstock on many frames. Also the "F" or no "F" in the 850 frame number stamped into the timing side of the headstock on 850 frames. There are theories on both but so far, no real proof or enough evidence to say.

TJBaker57 said:

I was just reading through old posts and discovered your earlier posts on the subject. Wondering if anyone has compiled any sort of listing that might allow speculation about what factory change prompted what letter.

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I don't think the reason for any of the gearbox letters is known so that could prove difficult.