Buyer beware.

Hi Alan,

   Yes as you say, but this bike is more than that. Looking at the parts it looks like it has been built up from what parts were available. This is not a bad thing and gives more enthusiasts a chance of getting a bike they want. The problem is the high prices that are paid and the authenticity, you wouldn't want to buy a machine for far more than what it's worth. We all need transparency for the good of everyone.

Hi David,

   I didn't think you thought I was that shallow. I have no personal interest in this bike as I have more than enough bikes already, so won't be bidding especially at Bonhams premiums. I posted this purely for the benefit of prospective owners who may not know enough information to make a decision on spending so much money. For the guide price you could buy 3 post-war singles.

   As for nit-picking, few of my bikes are 100% original, but honesty is the prime requesit. And just to support the above, please see the attached photo of what used to be my ride to work 1948 Model 18. Don't tell anyone but it even has BSA Bantam parts fitted.

Hi All,

   This is the full catalogue descripion including the sale price, just hope the new owner is not too disappointed.

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The Spring Sale / 1937 Norton 490cc Model 30 International Racing Motorcycle Frame no. 30 71953 Engine no. 78494

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LOT 492

1937 Norton 490cc Model 30 International Racing Motorcycle

Registration no. not registered Frame no. 30 71953 Engine no. 78494

Amended

THE SPRING SALE - THE INTERNATIONAL CLASSIC MOTORCYCLE SHOW

23 April 2022, 10:00 BST

Stafford, Staffordshire County Showground

Sold for £18,400 inc. premium

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1937 Norton 490cc Model 30 International Racing Motorcycle
Registration no. not registered
Frame no. 30 71953
Engine no. 78494

• Fully rebuilt in 2017
• Engine rebuilt by Bernie Allen
• Last run at Donington Park in August 2019.

One of the most charismatic model names in motorcycling history, 'International' was first used by Norton for its top-of-the-range sports roadster in 1932. Following its successful Senior TT-winning debut in 1927, the overhead-camshaft Norton had enjoyed mixed fortunes in the Isle of Man, and when the engine's designer, Walter Moore, left to join NSU, Arthur Carroll was charged with carrying out an extensive redesign. First seen in the works racers in 1930, the new motor borrowed features from the successful KTT Velocette, contriving to look very different from its predecessor while remaining unmistakably Norton in execution. The Carroll engine retained the classic 79x100mm bore/stroke dimensions and shaft-and-bevels cam drive of the Moore unit but shifted the magneto drive to the right-hand end of the crankshaft where it was enclosed in a distinctive timing case. The new overhead-cam racer was not an immediate success - 1930 was Rudge's year in the Isle of Man - but came good in 1931 when works rider Tim Hunt kick-started a four-year period of Norton TT domination by winning both the Junior and Senior events. Towards the end of 1930, the Carroll-type engine was introduced on the CS and CJ road models, and in 1932 these were joined by a new top-of-the-range sports roadster - the International or 'Inter' - that bore a closer resemblance to the works racers and was equally at home on the track.

Based on the works bikes and intended primarily for racing, the International could nevertheless be ordered with refinements such as lights and a kickstarter-equipped gearbox. By the time production halted in 1939 it was being built with a four-speed foot-change 'box and plunger rear suspension (the 'Garden Gate' frame), reappearing after the war in similar guise save for the adoption of the hydraulically-damped Roadholder front fork, replacing the pre-war girder. The Inter remained fundamentally unchanged until 1953 when it gained the race-developed Featherbed frame, an all-alloy engine, and the 'laid down' gearbox.

The vendor advises us that this International was assembled from a collection of parts. Notable features include a post-war Manx-type double-overhead-camshaft cylinder head; telescopic steering damper; Smiths tachometer; modern racing tyres; twin-leading-shoe front brake; and modified footrests/controls. The machine was fully rebuilt in 2017, the engine (which runs on methanol) being overhauled by Bernie Allen with a new big-end bearing and high-compression piston, while the gearbox was rebuilt by Bernie at the same time. The Norton was last run at Donington Park in August 2019.
Offered without key

Footnotes

All lots are sold 'as is/where is' and Bidders must satisfy themselves as to the provenance, condition, age, completeness and originality prior to bidding

Saleroom notices

The machine is offered with some extensive SCR Classics invoices and some technical info/drawings.

Hi all,

   To support my previous comments I thought I would list the parts used to build this bike.

The frame is from a post-war Model 18 or 16H/Big4, and the forks are from a 1939 bike of the same type. The front wheel looks like a very early tele fork model and the rear could be of a similar period, both with 19" rims. The twin leading shoe brake is a one-off fitted in a standard 7" hub. I'm fairly sure the petrol tank is a british made replica made to post-war standard specification, and the oil tank may also be too, but to early '30s wrap around pattern. Some of the detailed work looks a bit dodgy and fasteners could do with replacing with period pattern parts and more care with brackets etc.

The engine bottom half and cambox are probably the only parts of the bike that date from 1937. The barrel and head are from a circa 1952 DOHC Manx but fitted with the standard alloy SOHC cambox as a DOHC cambox will not fit in this frame. Note the alloy block between the crankcase and barrel made to blend in with the cases and counteract the shorter barrel. The carb and magneto look O.K. for 1937, but not necessarily from that year. The racing gearbox is probably post-war as pre-war they had the ratios stamped on the back.

I'm not knocking any of the above specification as I am planning building an engine along the same lines, but as said earlier, just tell it straight and it won't be a problem.

Hi David,

   To answer your question of the cambox on the sale bike, the head and barrel are from an early featherbed Manx, but the cambox is the standard Inter alloy type. This will fit, but you might have to adjust the height to get the best contact with valve and rocker. You cannot fit a DOHC cambox to the earlier SOHC head due to the different valve angle as it is not possible to get the pushers and valve to contact correctly. The DOHC garden-gate Manx frame has a very large bend in the top tube to clear the cambox and the earlier frames will not have enough clearance to take the DOHC engine. Jon has a DOHC frame on his machine.

Tomas,

   The picture Jon has posted shows the Bowden mag and air levers fitted to the racing specification Inters from 1936 onwards. These are not the best quality and look like they come from a grass motor-mower, but they were original equipment. The brake and clutch levers should also be Bowden and are the straight blade type, but as David says these are not allowed for racing today. Ken MacIntosh from New Zealand makes 7/8" (22.2mm) diameter replicas of these parts, but just the air and mag levers cost around Eu.300+ per pair. The standard road specification Inters used Amal levers and controls the same as the other Norton models. The throttle twist-grip would also be Amal and the pre-war ones would be chrome plated brass. If you try to find original parts, this could take a long time, so as David says get it going and then look for the original parts later.

P.S. Not an expert but have picked up some info after 49 years of ownership.