New member ,buying a International 1939

Hi Peter,

   Welcome to the NOC. I can see the forks are from a 1946 Model 18 or 16H. There are many of these bikes built up from spare non original parts, so you need to factor this in to the asking price. A full photo from each side will help identify how original this is. I may have seen this bike before, is it in the USA ?                                                        

There are a few differences between the frames of the ES2 and International.  It's not easy to tell from the picture.  Hardly anyone will know or care, but it perhaps might affect price slightly.  Except that not a lot are sold so there is no fixed guide price! Obviously it looks very pretty.
Richard has mentioned the forks.  The lengths of 16H and Inter forks are identical, so they won't affect the ride, even though the Inter has a larger front wheel (21" instead of 19")  The Inter did not have the same interchangeable front and rear wheels, so the front hub was a bit lighter and narrower, and brake adjuster was high up.  Inters had 20" rear wheels, but lots have been changed to 19" with a larger tyre because 20" rim size rear tyres are hard to find (impossible?)
ES2 rear suspension plungers were vertical, but Inter ones sloped forward at the top.  This was because the Inter had lower ground clearance and the engine sat lower, so a line bisecting the line of the plungers had to slope down to be in line with the gearbox main shaft.  A side view will confirm which is which.  It won't make much (if any) practical difference.  Inter brake plates were chrome plated.  That gives you the excuse to make it even shinier than it already is!
I wouldn't let any of that put you off unless you are absolutely obsessive and want to chase concours cups at a venue where the judges will know (which is unlikely even in UK).
They are great fun to ride, but don't wear a white suit.  It takes a lot of expertise (and I suspect luck) to stop the open valve gear from splashing oil about.
The fuel tanks does not have the 'pie crust' soldered lower edge.  I suspect welded tanks were made in late 30's.  Mine is also welded, so yours isn't unique.  Its painted in 'road' not 'racing' pattern.  That appears to have been normal for road bikes, even though lots of owners painted them with the broad black racing pattern lines.
Mechanical condition is important.  An engine rebuild is not for the faint hearted with no prior experience.
Pretty much every Inter is different today...

Welcome to the NOC , personally I think you SHOULD wear a white suit, it would help with the heat in Texas. 

There are many experts in the NOC who will make sure you don't buy a pig in a poke but as I often say a pig in a poke is better than no pig at all ( unless you pay to much for it )
Good luck with your international buying and hopefully see you on it soon !

CS would mean a CS1 when it left the factory, not an International.  Much the same engine but with cams, carburettor and gear ratios set up for road use rather than racing.  Lots of CS1 were tuned for racing.
Visible differences include;
Inters has TT carb.  No tickover (unless modified).
Inters had parallel front forks.  The four girder fork spindles are the same length.  I imagine yours are correct for CS1, but someone else might know.
CS1 had 19" rims front and rear.  Probably interchangeable wheels.
CS1 carburettor inlet was horizontal, not sloping down.
Inters had gear ratios stamped on the back face of the box.  2.12  1.33 1.1 1
CS1 might be stamped 2.98 1.61 1.21 1

CS1 don't seem to have been made in the same numbers as Internationals. But their gear ratios are more logical for the road.  Very similar to Commando and Dominator.

Hi Peter,

   The engine number dates from 1937 and the frame number would be late 1938. I'm quite sure this frame is post-war as the 1939 frames did not have centre stands. It is possible this number has been sourced from the factory records and applied to this machine. The girder forks cannot be identified by the brake cable lug alone as these changed a couple of times during the 1930s period. The forks on this bike can be identified by the the headlamp brackets as these were only used for the 1946 season and never fitted to Inters. These would have been the splayed type which makes me think they could have been made parallel professionally or simply squeezed, bending the lower tubes. These do not have the Andre damper as there is no anchorage on the post-war frames. The tanks look to be post-war as is the front wheel.
   If you are happy with the bike as it is, make sure everything is above board as there are a lot of scammed bikes and parts appearing on the internet these days.
   

If you go to "vintagenorton" Web site, you will find downloadable copies of pre WW2 Norton brochures.  Pictures can't always be trusted in all details but they should be helpful.  There are also various downloadable technical files.
When optional plungers arrived in 1938, the rear drop down stand was discontinued.  So centre stands (they described as 'prop stand') had to be used instead.  The 'prop stand' had already appeared on rigid frame bikes a few years earlier.
Someone else might confirm when the forward facing 'suicide stand' was fitted.

Hi Peter/David,

   It looks like someone is making a business of making 1939 Inters ??
I, and many others, cannot understand why the 1939 frames had the forward facing rear stand when the older type plunger frame had a conventional centre stand. This was an Edgar Franks design and was fitted to all, new for the 1939 season, plunger frames including the Manx Grand Prix racers leaping over Ballaugh Bridge in the Isle of Man ! These were fitted from September 1938 until the out-break of WW2 a year later. I have attached photos of my 1939 stand FYI.

Another photo with the stand up.

Perhaps the reason for the new stand was that the original centre prop stand was only suitable for parking on a flat floor?  My 1937 16H one is not very secure on even slightly uneven ground.  It doesn't lift the bike off its wheels, so is no help when changing a tyre.

I think you (Richard) were correct in your post in 2019...the sloping plungers keep the wheel movement at right angles to the line through the sprocket centres of the rear chain because frame is lower at the front than ES2.

... is governed by the primary and secondary sprocket ratios not the gearbox as top gear is direct drive. You've probably got a sidecar engine sprocket in there.

Looks like a nice bike and plenty to keep you busy!

The gearbox usually has the ratios it left the factory with stamped near the top of the rear upright face.  Standard road ratio boxes might not be stamped.  Look for 2.98 for standard box.

According to Bacon's 'Norton Singles' (which you should try and find), the only non standard ratios were Inters and Big 4 WD. So unless you have a trials bike gearbox, there's unlikely to be any point changing internals.
There are at least three different offsets for engine sprockets.  RGM have them I believe. Your clutch should have 42.  Gearbox 19.  Rear wheel 42
Engine 20

Mine runs up to and beyond (allegedly) our 70mph legal limit.  It's got plenty to spare but my mechanical sympathy cuts in first. They were allegedly intended to run at approaching 6000 rpm for 3 hours to win the TT.  Then to be rebuilt...expensively today!

There were only 2 types of fork.  Inters (models 30 and 40) and the rest (including CS1).  The overall lengths are the same, so its origin is immaterial.  The 30 had a bigger wheel and its mudguard bracket is shorter to give clearance.
It sounds like you might just need to change engine sprocket and have fun. Effectively it seems it's a near standard CS1.  What carburettor?