Seems like a 750 serial number on an 850 (2008)

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Well Wrench, what I am saying is that I am talking to the current owner that has owned the bike since it was months old and his friend that he bought it from owned those few months. He has all of the paper work, etc to back that up. On this matter, I was born at night, it just wasn't last night. I see in this case no reason or attempt to deceive.

As to the numbers and my experience with stamping them, the numbers that are there (plate, gear box, and crankcase) and which all match have all the appearances of not being tampered with at all as was suggested earlier in this post. Yeah, the world really could be square but I am trying to convey to people on this board what I am seeing and what I believe to be the case. To add to that, I am not making any assumptions on the frame. My only concern is to sort out the identification of the three matching numbers on the plate, gearbox and motor.
 
Wrench, I didn't mean to come across defensive. At work, I had people questioning my direct observations. During the 1980s I built a product that we serial numbered. There would only be two ways of changing an actual number stamped into metal, either an unsophisticated attempt or a much more sophisticated attempt. They would both have their clues for the metal worker.
 
To Ron L,
RH7 head difference: bigger inlet valves with thinner stem, reduced valve angle, squishbandless hemisphere to suit the high compression Omega pistons. Hard to find one nowadays!
 
Nortonspeed,
Sounds like you have first hand experience with the shortstroke. Care to elaborate?
 
As to the original bike in question on this post, I think I have learned enough from all of you to take it full circle. I saw it again last night and checked the cylinder head designation and frame number. It is an RH10 head and the frame number is: mark (same as used on motor for an 850 - circle with two verticle lines through it) 850 mark F107752 mark. Based on the head designation and my measurement of the stroke, I am convinced that it is a standard 850. As to the unusual serial number (235XXX), I belive it is just as Les said, "another one of those unsolved Norton mysteries."

Thanks for all the input; I sure learned a lot. Too bad it didn't turn out to be something a little more interesting.
 
Yellow_Cad said:
Wrench, I didn't mean to come across defensive. At work, I had people questioning my direct observations. During the 1980s I built a product that we serial numbered. There would only be two ways of changing an actual number stamped into metal, either an unsophisticated attempt or a much more sophisticated attempt. They would both have their clues for the metal worker.
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No worries Yellow_Cad, you didn't come off defensive at all, was just curious. It is/was a nice Norton mystery though(!).

wrench
 
Yellow-cad - How can anything be more interesting than a Commando that says "Buy me" ? :)

Perhaps a silly question but have you looked at Dave Comeau's frame number site ?

http://atlanticgreen.com/commandoframes.htm

He has F107761 which must be very close on the time-line to yours tied in with engine 317462 and the 4/74 date fits but of course the other numbers are enigmatic to say the least.

Norton's records for export sales were always a bit sketchy, even pre-war. I think that once a bike was shipped overseas, it became the responsibility of the importer and they had no interest in it. Is there no-one in the U.S. who has managed to trace the old Norton Triumph Corporation or Berliner import records ?

Are you going to follow up the VMCC line of enquiry or would you like me to have a word with the Librarian there ?
 
As of a few days ago, I sent the inquiries regarding the serial number to VMCC and UK NOC. I have not received any responses yet but did get an email from one saying that they had forwared it on to their library. I will post any responses I get.

I did make an offer for the bike but of course it was not quite what it would have been had it been the short stroke. But as I was leaving, I looked at the bike and I swear it was saying to me, "I can do anything the short stroke can do; just fix me up and give me a chance."
 
Another 235,xxx bike, an 850, with the unusual stamping pattern of an extra "1" plus extra circle mark, is being discussed over on facebook here:






LAB: There are a many dead URL links still remaining in several of the threads on accessnorton, in regards to bikes with 235K serial numbers, including in posts made by yourself.
 
huh, seems both 750 and 850 with 235xxx
 

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Robert_Norton said:
LAB: There are a many dead URL links still remaining in several of the threads on accessnorton, in regards to bikes with 235K serial numbers, including in posts made by yourself.
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Thanks. If I see one then I try to fix it, however, it isn't always possible.

illf8ed said:
huh, seems both 750 and 850 with 235xxx
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Yes, up to (approximately) 235500 seem to have been mainly 750 Hi-Riders, some drum brake Roadsters and 750 short-stroke engines and a few 235500+ were 850s.

The '235' series factory records no longer exist it seems, except for 235510-235515 held by Andover Norton.

andover-norton.co.uk

Factory Records

andover-norton.co.uk
 
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Had one high number 200k here in northern new england.
Shop owner conferred with me and other sources in england.
Final decision was ...bike was bought as homologated short stroke.
Valuable engine guts totally stripped out for race resources and replaced with "bone stock" 750 parts then bike resold.

I have also seen first hand a plain 850 non e-start with matching numbers above 325K.
 
Unless 73mm bore '750' barrels (and 750 cylinder head) also replaced the 77mm bore short-stroke barrels then fitting a standard (89mm) crank and (77mm) pistons would convert it to an '850'.
 
Robert_Norton said:
Another 235,xxx bike, an 850, with the unusual stamping pattern of an extra "1" plus extra circle mark, is being discussed over on facebook...
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Has ANYONE here ever seen this unusual secondary stamping?

A fellow (on fecebook) who worked at Norton recording serial numbers said even HE had never seen one like this...
 
grandpaul said:
Has ANYONE here ever seen this unusual secondary stamping?

A fellow (on fecebook) who worked at Norton recording serial numbers said even HE had never seen one like this...
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I saw this too.

At risk of being controversial... just because a single ex-employee didn't see it happen (over 45 years ago... even I don't remember everything from that far back!), doesn't mean it never happened, especially if it had gone through the race shop (or whatever they had back then)

The 'rebuilt to standard' ex-short stroke motor theory would be a plausible explanation, and the example posted certainly doesn't look to have been interfered with.

One for the X-Files....
 
grandpaul said:
Has ANYONE here ever seen this unusual secondary stamping?
Click to expand...

*235638*1*

One of "Those" ebay ads

http://cgi.ebay.com/ebaymotors/Norton-8 ... 500wt_1182 The serial number begins 23553_. shouldn't it start with a "3"; it has a drum rear brake; no starter with left shifter etc, chaincase, timing cover etc. etc. The seller added someone's info to the bottom of the ad stating it is a 74 sold...
www.accessnorton.com www.accessnorton.com
79x100 said:
On a whim, I just decided to pull out one of the old analogue photo albums and there staring at me is a photograph of a very original Mk2A numbered 235638 and with a '1' between the circle stamps.
Click to expand...
 
L.A.B. said:
Unless 73mm bore '750' barrels (and 750 cylinder head) also replaced the 77mm bore short-stroke barrels then fitting a standard (89mm) crank and (77mm) pistons would convert it to an '850'.
Click to expand...
IIRC engine totally stripped to bare # cases. I didn't personally see the bike/engine though I might call the shop for a refresher.
A local racer (old guy builder) 25 years ago ran a 750SS at local races and it was a very dominant noticeable screamer with a kid on it for a pilot.

Thinking that any 850 case can be assembled with a 750 or 850 top end.
Any 20M3S+ 750 case can be built as an 850 if you bore out the case mouth to accept the barrels.
The medium or large bolt pattern heads must match the barrels .
Short stroke heads RH7 P89/2 or RH8 Race Kit would be large bolt pattern.
 
A guy on fecebook posted this one...

Seems like a 750 serial number on an 850 (2008)


He included this caption: "This engine I bought as a 750 short stroke, also with 850 cylinder block. Numbers don’t seem to be far away from the other engine, but this one without the extra number and rondelle."

MAYBE THE POSITION OF THE STATOR STUD HOLES IS A CLUE?
 
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