Thursday, June 15, 2023

Norton Numbering System

I have seen much confusion over the numbering system adopted by Norton, and most online sources for decoding are erroneous. A very useful table can be found in Bruce Main-Smith's Norton Motorcycles 1928-1955. A full copy of this can be found under the "Norton Literature" tab above.


Prewar machines do not have matching numbers, frame and engine numbers incremented independently. Military models also follow this sequence. After the war, Norton restarted at 1000, prefixing the number with a letter denoting the year, and a number denoting the model, followed by the engine and frame numbers which match. For example, L14 65333 would denote a 1956 Model 99 Dominator twin, which would be stamped on both the LHS of the engine crankcases, and on the LHS frame gusset above the swingarm spindle. The frame was stamped on dispatch through the paint.
-BC

Tuesday, June 13, 2023

Manx Section Added to Website

We are glad to announce that we have expanded the library to include Manx parts lists and manuals. There are a number of original documents published by Norton Motors, as well as tuning tips from the day from people such as Francis Beart and John Tickle. Either click on the tab up the top right of the website, or click here.

-BC

Tuesday, February 14, 2023

1963 30M Manx

This is the highest number 500cc Manx from the last production run built at the Bracebridge Street, Birmingham factory race shop- Frame and engine number 102818. Built to full race specification, this 500cc DOHC short stroke, still retains many original parts often missing on such machines. 

All postwar Norton's have matching numbers because the stampings were only done after the bikes were assembled. The frame numbers are stamped through the paint!

102818 was sold new in California and was restored by Norton enthusiast Paul Adams, who stored the bike in New Zealand and returned each year to race it at the famous annual Pukekohe Classic Festival for over 13 years, until Covid hit.

The 1962-63 Manx build of over 110 bikes were consecutively numbered but the last 40 odd were built in January 1963. In this last batch there was a 350 built, 102819, one number higher than Paul's 500. This was sold in Aberdeen, Scotland. Remarkably it ended up in Texas at an auction in the late 1970's and was also bought by Paul Adams, who raced it in the Manx GP. For many years he didn't realize he had both.

In the Norton dispatch records there shows a final two bikes built after Norton production was moved to the AMC factory in London. 105047 (500cc 30M) went to (Syd) Lawton and Wilson, Southampton on 1st August 1963, and 105048 (350cc 40M) left Bracebridge Street on 28th January 1963 for AMC at Plumstead, London and on 29th April 1963 to Tom Kirby in Hornchurch for J.W. King. Why these bikes were not numbered in the same sequence is not clear, but Tom Kirby and Syd Lawton were both major racing sponsors at that time.

This ex USA 1963 Manx has a magnesium engine, original specification AMC four-speed close ratio gearbox, a Featherbed frame and Roadholder telescopic forks. The front brake is the correct double-sided twin leading shoe with AM4 linings, giving good bite after warming up. The wheels are the original narrow 19" Borrani rims used on all Featherbed Manxes after Norton's falling out with Dunlop in the early 50's. The photos reveal some of the minor flaws reminiscent of its racing history, including the missing air lever, dented tank, and damaged chain oiler, which is still fitted and correctly plumbed but not used with the O-ring chain fitted. It even has the original chain rubbing pad fitted behing the swingarm spindle. The bike was originally dispatched to California, via Berliner Motors of New Jersey and raced locally until an engine failure and was subsequently stored for 30+ years. 

The engine was fully rebuilt by McIntosh Racing using a kit of factory "new old stock" spares which came with the bike, The rest of the bike had been restored by then owner Paul Adams before being sent to New Zealand. 

After this Paul Adams rode it for many years at the Pukekohe and Hampton Downs circuits in New Zealand. In his own words;

I got the 63 Manx as part of a trade with a friend for the remains of some of Nortons' Daytona bikes of the late 40s early 50s. He had got the Manx in trade from an acquaintance in Ventura, California. I don't know who raced it and it was mostly disassembled, including the engine. The engine needed attention and it looked like it had let go early on because the chassis parts exhibited little wear and tear. The rear mudguard still has the original factory finish and Norton gold transfer, but I restored everything else. A testimonial to Ken and Pete is that the engine has held together splendidly through all my best efforts. I always tried to never exceed the 7200 rpm max.


















Ben Creemers continues the story "the bike was bought in 2021 by my father, Robert Creemers, who now lets me ride it like it isn't mine... because it isn't! It arrived in New Zealand early this year, and requiring minimal work aside from some jetting, a new plug, and some fresh clutch plates. It performed well at the NZCMRR classic festival at Pukekohe, finishing ahead of some of the six-speed replica Manxes. The starts are certainly challenging with such a tall first gear, and the bike is left in the dust of the others at the beginning of the race." 

Ken recalls that the bike's output was 42 horsepower at  the rear wheel on the Dynojet dynamometer, after the engine was first rebuilt with 100% standard Norton NOS parts, which is about 47 horsepower at the crank. Probably about average for an "over the counter" 1963 Manx.




Photos courtesy of Keith Milne (bike photos) and Grant Paterson (racing photos).
- BC



1947 Norton 350T


Robert Dixon of Portstewart, Northern Ireland kindly sent in some images of a 1947 Norton 350T he has restored, both prior to and after restoration. In his own words;

Please find the pictures of a 1947 350T Norton. You can see how the top tube is bent upwards and the front down tube with a double kink. This was done by the factory to shorten the wheelbase by I believe 1.5 inches. The engine is cast iron, so the bike is quite heavy and on the day was useless as it was to heavy and slow. The 500T replaced the 350T. In 1947 only 7 350Ts were produced. You will get someone stating the tank is not correct, but I had to cut and shut another tank as the original was missing. 








The 350T can be seen offered in the 1947 catalogue as a 'trials' model, available as 350 or 490cc.


- BC

Wednesday, December 28, 2022

1948 Norton Manx 30M 499cc

This 1948 Gardengate Manx came to New Zealand from California as a basket-case as part of a swap with noted Norton restorer Paul Adams. The bike was originally supplied to McGill, the Canadian and North American Norton importer. It spent most of its life owned by the famous Californian Norton tuner Clarence Czysz, and was probably raced at Daytona by Czysz’s rider Tex Luse. Unfortunately no records exist.


The bike has been restored by Ken McIntosh to the more common Isle of Man rather than the American Class C” specification mainly because the “Class C” requirement of a working kick-starter meant the exhaust pipe would be rather low. Although no problem at Daytona Beach with only left turns, it is a major problem on New Zealand circuits.



The Manx specification remains fairly constant in the 1946-49 period, with the main change for 1948 being the introduction of welded steel oil and petrol tanks, replacing the pre-war type soldered tanks with their nice “pie-crust” edges.

 

The 79.6mm x 100mm SOHC motor has magnesium major castings, with the square finned aluminium cylinder head being cast around a bronze skull instead of having inserted valve seats, and the aluminium cylinder has the cast iron liner, also cast in. The bronze skull is a feature of all Manx engines until 1951.


 

The close ratio 4 speed “Dolls-head” gearbox has no kick starter and a very high ratio (1.77 -1) first gear, meaning over 70 mph at maximum (6200rpm) revs with Isle of Man gearing.

 

The 3 plate clutch is special to a Manx and runs dry. The primary and rear chains are eachlubricated by an adjustable vintage type drip oiler from the 1 gallon oil tank. The bike uses pure SAE 50 Castor oil. This bike is fitted with an “O” ring primary chain which can happily run dry.

 


The correct BT-H (British Thompson-Houston) “TT Magneto” is fitted along with the correct Amal T10RN (remote needle) carburettor and Amal bottom feed float bowl.
 


The Smith 8000rpm RC83 “Chronometric” tachometer is correctly rubber mounted on the left fork leg, with the rather vulnerable brass drive gearbox mounted low on the timing cover. This is because the large AndrĂ© steering damper mounted in the centre of the fork stem precludes the later central mounting of the tachometer


The single leading shoe 8” conical iron front hub has magnesium shoes and brake plate. Fitted with Ferodo AM4 linings it works well, when combined with the very heavy cable and long front brake lever. The bike came from the USA with the original woven asbestos linings fitted and they hardly worked at all!

 

All the handlebar levers are special to the Manx with the brake lever being extra long and the shorter clutch lever having a long throw to give enough lift for the clutch. The lever bases are made of brass and are much more solid (and rigid) than the standard road type. The pressed steel air and magneto levers are only used on the racing models (and possibly lawn mowers), and being made of sheet steel rather than cast metal, they are very light weight.



The Dunlop steel wheel rims (alloy rims were an optional extra) were normally painted black, with a WM1 (1.65” inside width) x 21” front and a WM2 (1.85”) x 20” rear. The bike is fitted with a 19” rear tyre so an Avon GP race tyre can be used. The slight reduction in diameter appears to cause no problems.


 

The Terry spring saddle and Norton-made hinged rear seat are peculiar to the post-war Garden Gate Manx models and are set rather high giving a strange riding position. At first it feels rather odd but actually turns out to be quite comfortable. You certainly feel “on top” of this bike.


 

The front forks are unusual in having a lower yoke with a bigger off-set than the top, adding about 3 degrees to the fork angle, giving the bike a very long, raked-out appearance. This geometry means the bike has quite small amount of trail (compared to a featherbed Norton) and relies on the 21” wheel for stability. These models have a reputation for bad handling when compared with the later Featherbed, and even the pre-war girder forked models, with weaving and pitching combining to unsettle all but the bravest of riders. After riding this bike, the famous journalist Alan Cathcart expressed surprise at how well it handled, having ridden similar models before.


 

The answer lies in the front fork damping. The pre-1950 Manx models use the same damping system as the standard post-war Norton road models. This is really only a hydraulic bump-stop in both directions, and offers no damping at all for the normal fork travel. Hugh Anderson advised me during restoration of his experiences with plunger frames and early Nortons, and said much of the criticism levelled at the frame and plunger suspension was actually the lack of fork damping. When I suggested that originality was important, he added that so was not falling off! The answer was to fit the piston type damper that Norton first used in the 1950 Gardengate Manx, and later in every Featherbed and Commando model. This does not change the appearance at all and transforms the bike into a nice handling machine even at well over 100mph.

 


The bike has a very nice motor with almost no vibration, and is happy to rev over 6000rpm without complaint. If ridden on the open road, the high first gear means a fairly brisk push to get the engine started. Once running, the high first gear is quite easy to live with and does not require too much clutch slip.


The RN carburettor has a reputation for being troublesome, but has been found to be near perfect with no flat spots at all. Its one strange characteristic is if the bike is leaned towards the left when idling, it will stop dead, and if push started from the left side it is reluctant to start unless flooded (to raise the fuel level). Raising the fuel level in the float bowl has not cured the problem. It is quickly learned it is essential to only lean the bike to the right when warming up, and people who push start on the right-hand side are at an advantage!


 

Manx Nortons were often run on alcohol fuel in Australia and New Zealand, and some non Championship UK events. The normal Amal RN was classed by Amal as unsuitable for alcohol because of its convoluted fuel passages. The TT carburettor as used on International models was highly suitable with the huge jets and high feed float bowl available for this very purpose. Forged pistons were available from Norton giving up to 14:1 compression ratio to suit any type of fuel. The “Pool” petrol (70 octane)  available for a few years after WW2 was used in Grand Prix and TT racing and would only stand about 7:1 ratio without terrible, destructive detonation. Norton supplied suitable forged ‘flat top’ pistons.


 

As part of the AMA “Class C” regulations used at Daytona, 500cc OHV engines were restricted to 8.5:1 compression ratio to help the Harley-Davidson and Indian Side-Valve 750’s which struggle to achieve 7:1. With the 100 octane available in the USA, the Manx would have run happily at well over 10:1, giving a few more BHP.


 

I think the Garden-gate Manx is the last “Vintage” motorcycle made by the British Industry and is the final development of the pre-war bikes, before being completely surpassed by the Featherbed models in 1951.


Ken

Monday, December 26, 2022

1950 Works Norton

This is the only surviving 1950 "Works" Norton, owned by Mr Peter Bloore and restored in New Zealand by Ken McIntosh and McIntosh Racing.

The "Featherbed" Norton and Geoff Duke were made for each other. Geoff Duke's new style of "always tucked in" riding became practical, because of the new standard of motorcycle roadholding set by the Rex McCandless designed frame. The 1950 Featherbed was described by Geoff Duke in his book as the "best handling motorcycle he ever rode".

The name "Featherbed" was coined by 1949 Senior TT winner Harold Daniel who is reported to have said "It was so comfortable it is like riding on a Featherbed". The Featherbed Norton changed motorcycle racing from a horsepower contest to a roadholding contest. The entire chassis and suspension was designed and built "hands on" by Rex McCandless and his small team from Belfast.

Artie Bell, winner of the 1948 Senior TT on a “Garden-gate” Works Norton, was Rex McCandless' business partner and was responsible for most of the testing and development of the prototype "Featherbed". The new frame and a small increase in power gave Norton a clean sweep in 1950, with the Junior/Senior "Double" and first, second, and third places, plus Lap and Race Records in both classes.

Norton works Team 1950. From left; IoM Governor, Norton team riders Jonny Lockett, Harold Daniel,  Artie Bell, Geoff Duke and Norton boss Gilbert Smith.

Geoff Duke graduated from being a new and junior member of the Norton Works team, to being the leading rider in a week, after gaining second place in the Junior TT behind team-mate Artie Bell, and then dominating the Senior TT including smashing the lap record, set by Harold Daniel’s Works Norton in 1938.

The Norton Featherbed became a production motorcycle using Rex McCandless' design and patents, for which in the early years the McCandless and Bell partnership were paid a £1 royalty for each machine sold.

Rex McCandless and his welder, Oliver Nelson, came over from Belfast and set up in a disused cart dock at Bracebridge Street. With their own jig, they built the first 10 frames for the Works Team, when Norton could not get anyone else to take on the job.

Possibly the only photo of a naked 1950 Works frame. Some of the repairs can be seen. It had suffered a head on crash before Peter Bloore found it at the Beaulie Autojumble. Luckily it was easy to straighten and the brackets that had been cut off left traces of bronze, so they could be refitted in the exact position. I think it is safe to say that without this lucky find, there would be no 1950 Works Nortons left in existence.

The 1950 "Works" Nortons used the only Featherbed frames that were ever made in the Norton Factory at Bracebridge St, Birmingham. All the other thousands of Featherbed Manx, Inter and road frames were made by Reynolds Tubing Ltd under contract until the final ones in 1970. The Featherbed frame continued to be the standard by which all other road and racing motorcycles were judged until well into the 1970s.

The rear shock absorbers were made by Rex McCandless, and have a reservoir built in to stop the oil overheating and cavitating. Rex McCandless held a patent for the design, but Norton used other shock absorber manufacturers the following year. Geoff Duke later wrote the McCandless units were the best shock absorbers he had used.

McCandless and Bell were responsible for establishing the front fork geometries, angles and off-sets. McCandless fabricated the fork yokes by welding, and also modified the fork legs from the 1948 Works "Gardengate". This geometry was never changed during the production life of the Featherbed.

Bruce Anstey's 108.1 lap in last 2014 Classic TT was achieved using a completely standard design and original spec Manx Featherbed frame (built by McIntosh Racing) which is essentially the production version of the 1950 McCandless design.

The only surviving 1950 Works Norton was rebuilt by McIntosh Racing in New Zealand using the only known original 1950 Works frame which was found at Beaulie Autojumble in the 1980's. The owner, Mr Peter Bloore, then embarked on a 30-year search for the missing parts.

Many of the original 1950 parts had seen further service in the later Works bikes, and were very difficult to acquire.

The 8 1950 Works Nortons were all dismantled at the end of 1950, as the parts were used to build the updated 1951 team bikes. The only survivor, in modified form, was Eric Oliver's 1951 World Championship winning Sidecar outfit which was based on a 1950 Works 500. Eric used the experimental leading axle forks first seen on some of the Works Gardengate models in 1949, and then in shortened form on the McCandless built prototype Featherbed in late 1949. The 1950 Works bikes used centre-axle forks derived from the 1948 Works type.

This bike took over 2000 hours labour to restore, as every part is special. Almost no Manx Norton parts are the same as the 1950 Works, although nearly every part forms the prototype for the production Manx Norton 30M and 40M models.













Peter Duke with the 1950 Works Norton and Senior TT Trophy at the Isle of Man Classic TT in 2015

Kiwi Bruce Anstey leading the Geoff Duke “Lap of Honour” on the Isle of Man in 2015.

Australian Cameron Donald, twice TT Winner and now TV commentator lead the TT Lap of Honour away in 2017, giving Peter Bloore’s Works Norton a good fast run on its natural playground. He stands behind the wonderful picture of Geoff Duke taken in 1950 at Hillberry. Davida Helmets provided both Cameron and Bruce Anstey with the correctly painted and stickered 1950 Geoff Duke “pudding basin” helmets.

Cameron Donald 2017

TV presenter Henry Cole and the late Dr Geo Cohen, IoM classic TT 2015

Long time tester of McIntosh built bikes, and now officially a “MotoGP Legend” Hugh Anderson. Although his World Championship titles were on 2 stroke Suzuki models in the 1960s, he has done more miles on Manx Nortons,  G50s and 7Rs than most other riders anywhere, and has always offered great help and encouragement to McIntosh Racing since the very beginning almost 50 years ago.


TT Legend John McGuiness tries the ’50 Works for fit at the 2015 Classic TT. He knew a lot about the history of this bike and the impact it had in TT history.


The late, great John Surtees, the only GP Champion on 2 and 4 wheels in serious discussion with Moto GP legend Kevin Schwantz at Goodwood in 2014 when Kevin and New Zealander Rodney O’Connor raced it in the Barry Sheen Trophy Race. A practice incident involving Kevin’s first ever attempted use of a left side brake pedal resulted in a spill and upset qualifying, but the second race did produce the fastest lap of the meeting for Kevin indicating “what might have been”.

John Surtees has restored a number of Works Nortons himself, but thought the 1950 was an “impossible dream”. He was totally supportive and supplied item such as the correct Works BTH magneto and patterns for the aluminium megaphone.

I was extremely proud to have his endorsement of the finished product.


No, not Joe and Geoff.  Ken and Kevin with Rodney O’Connor listening.  Goodwood Revival 2014