ID Confusion

:?: My '72 Commando Interstate (bought last July) is titled with the following VIN # - 20M3S444418. This is the number stamped into the base of the engine at the left side. (I traced it for the tag shop nearby as there was no title, only a New York State registration from the seller.

Having looked at other websites, particularly about the VIN# history, I think the number must be 20M3S144418. The first "4" looks pretty clear to me but it must be a "1" as there is no such number 444418.

Previous owner tells me this is a combat engine, and when he had it rebuilt by Carl Hakanson in MA (a few years ago) the bottom end bearings were replaced with proper superblends, etc. The barrel of my engine is black. It also has BB ignition and a single Mikuni. It has a lot of compression but my 230# dropped down starts it pretty easily. Seems to run very well once warm.

Any ideas to more definitely classify my bike? What else would define it as a combat?

Thanks, Stuart Ostroff

:arrow:

Late '71

I've noticed a bit of traffic lately regarding the '71 / '72 trasition point and offer up what I've seen/own:

I have a late matching numbers '71 (150906, dated 10/71), so late that it is actually registered as a '72.
It has all of the usual '71 model year give-aways: cam-timed breather, POS inboard kickstand mount, drum front brake (although not any more).

I also have an early matching numbers Combat (202322, dated 12/71), originally an interstate, now a fastback.
It has the usual give-aways as well: breather on rear of crankcase, '72+ kickstand lug, "C" stamped in the top front center of the head, disc front brake.

For what it's worth,

Derek

:arrow:

I have also believed that the amals for a combat engine are numbered 19 & 20 underneath the 932.

Can anyone confirm that information, or flame it, whatever you like.

As long as the final information is correct, that would be good.

I have also believed that the "C" was not always marked, but that could be a story made up unscrupulous sellers. Also, should it have been in the centre of the head, as I have seen some "offside" almost like some one has stamped it while the engine was in the frame & they weren't able to get the "C" deadcentre.

As with all the British motorcycle industry, Norton used up what parts they had on hand. It often follows no rhyme or reason, possibly due to them pre-assembling engine units and rolling chassis and completing them sometime later. You will find a superceded part on a bike with a VIN that is later than one you find the new part on. I have two '73 (MkIV) 750's, one with a build date of 11/72, and the other 1/73. I have found "improvements" on the 11/72 build that were not on the 1/73 and vice versa.

71/72 model year

Roy Bacon's Norton Twins Restoration book lists the '72 combat carbs as R932/19 and L932/20. That's what my combat came with.

Ron L mentioned inconsistency with earlier VINs dated later. I have a copy of a page from the Nov/Dec 71 factory records that lists into the 151xxx machines which were built to the '71 spec. My two combats built to '72 spec were made in Oct '71 (201123) AND Dec '71 (201881). Definitely some overlap and using up of stocks. From that I don't think the change to the MkIV model was late starting.

David,
That's interesting. I don't know why I never considered the fact that 15xxxx and 200xxx machines would be going down the line at the same time. How silly of me!!
Any idea when machine 200000 was built?

Thanks,

Derek
(Not losing sleep over this issue either, just curious!)

'71 vs '72 down the assembly line

I don't have the earliest numbers page for the '72 model year. The two pages I have start with 200180 and go through 200239. I think these pages are for machines that sat around the factory for a while before shipping. There isn't a build date only a ship date. 200180 shipped 15 Dec 71 to Kings Motors in Manchester and was a fastback with notation Mk4.

Some grist for the mill here.

Speaking of revisionist history, I thought you might enjoy this bit of correspondence from Norvil on the subject of dates and certification plates. (The bold formatting is mine.)

It is also not normal to have the month on a certification place, we have stamped it as it should be, we will not stamp a month on a certification plate because the months are all wrong.......... we will NOT stamp the incorrect information on any plate we supply.

Click to expand...

Any thoughts? - Do any of your plates have a month ? My original plate, (and I assume it was original considering the condition it was in -see pic on my site) said MAY 1970.

Phil.

:arrow: .

Yes, the Commando is a thief's dream isn't it? You can hotwire them in 30 secs with no tools, the VIN isn't stamped in the frame, you can buy a new ignition switch for $30 or less, and then just buy a new VIN plate, stamp whatever number you like on it, and there you go. Another bike for sale on ebay with a "lost" title...

Debby

Debby,

The frame on my '75 Commando has a unique Vehicle Identification Number stamped on the right-hand side of the steering head stock. Texas and Oklahoma, and I'm sure many more states, use this number for the VIN on the title.

This causes confusion as owners may look at the flimisy red tag for the VIN and find it doesn't match the title. I came across one e-bay seller in Oklahoma that claimed the title did not match the bike. In reality, he was looking at the tag number instead of the frame number. Upon closer inspection, the frame number matched the title perfectly.

"A Thiefs Dream" sounds like the basis for a great essay!

Regards,

Jason

Well folks, the good thing is that your current generation of typical inner city punk has no idea what a tickler or a kickstarter is, let alone the ambition to use them :wink:!!

Derek

Derek,

You're right, the average thief wouldn't have a clue how to start a Norton. I often leave the keys in my Norton while parked at a convenience, hardware, or autoparts store knowing that few people are capable of stealing it.

Also, fortunately for us, today's punk thieves don't think enough of a classic Norton to steal it.

Regards,

Jason

Still confused

Well, this is all interesting. A few days ago I retorqued my head and adjusted the valves to std spec's - .006 and .008. They were a bit loose, even AFTER retorquing. Hmmm. Then I got an e-mail from the former owner stating that it IS a combat, so I go out to the garage, pull the seat and tank, and readjust the valves for Combat spec's, .008 and .010. Then I read a few of these posts, than any 20M3S is definitely not a combat engine. WTF? Should I tighten them up again?

Fortunately, it only takes a few minutes to do the valves. I am used to the 12K services on my BMW K1200LT, with 16 valves, and if any are tight you need to pull one or both cams, do some math, go to the dealer and/or wait for Fedex, replace the buckets, reassemble, button up all the "tupperwear".

So - if my engine is a combat and its had the bottom end bearings replaced with the proper "superblends", that's fine. If it is not a combat, that's OK too.

Stuart

Stuart, the engine # does not match with a Combat. That # appears to be a 71. Also, the Interstate was not made in 71. You may have a 71 motor slipped into 72 chassis. The black barrells don't mean anything because it's been rebuilt, most people paint these black.

The easiest difference is the breather. According to your #, the breather should be coming off the left side of the cam, in front of the barrells. There will be a hose running along the primary. If not, is the casting smooth or is there a bolt plugging a hole where it used to be.
The Combat has a rear breather exiting in the cradle area. This also could have been modified to come out of the right side case.

Another possibility is you have a 71 case tuned to Combat specs. The Combat head is easy to identify, it has a C stamped on the top. Also, the spacing between the head and barrells is noticeably smaller than the spacing on the head and barrell fins. Because it is milled.
Even if it doesn't have a C, it could have been ported and milled
to Combat specs.

Even if all this checks out to be non Combat, it is possible you have a Combat cam, which is what determines the valve lash. Unforunately, there is no easy way check this. It would be great if you could talk to the mechanic who built it and find out.
I would probably run the 8 / 10 settings until I knew.

A source I use is Les Emery's web site, www.norvil.co.uk/ click on Indentify your bike, this may help.
Notice there are 5 Mark versions. It is interesting your numbers appear to fall in the second part of the 71 or Mark III.

HTH

Correction: www.norvilmotorcycle.co.uk/

On a second look, your numbers are very confusing.
Where is your tach drive and points located?

Details of my 72

The breather is clearly on the left, in front of the barrels, with the hose running rearward along the top of the primary. The points are at the front right corner. The tach drive is in along the front to the right of center. I just reintstalled it after having Phil at Fair Spares install a proper seal. And the oil doesn't spray out on my right foot any more.

I will leave the clearances at .008 and .010 until further notice - pretty quiet, ticks over smoothly.

Sounds like I have a '71 motor in a '72 Interstate frame. I realize only the seat, tank, and side panels make it an Interstate. Frankly, I don't care what the numbers all mean, assuming they assembled bikes based on what parts were handy on any particular day.

I am continuing to upgrade what I can, establish maintenance baselines. It starts pretty well and is WAY FUN to ride.

Thanks to all who have responded. WOW, 17 replies in less than 24 hrs.

Stuart Ostroff