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The 650 Norton thread

Norton Models (not Commando or P11)

The 650 Norton thread

Postby beng » Mon Oct 22, 2012 12:55 am

acotrel wrote:I don't know what barrels fit the 650 Norton bottom end, I don't think any other early Norton had twin carbs ?


The 650cc Norton would accept the parts of any earlier Norton Dominator engine, 750 cylinders/heads will not fit though as to accommodate the larger bore the four rear cylinder studs were moved back and the oil drain-back from the head was relocated, the four main head bolts of the 750 were made smaller in diameter and moved outwards too.

The first regular production Norton twin with twin carburettors would be the Model 99 Nomad Scrambler which was built from 1958-1960, twin carbs were also an option on very late 50s wideline Dominators though.
The 650 Manxman was the first model with the 89mm stroke crank and 1 3/4" crankpins though and the down-draught head. The Atlas and 750/850 Commando were the same as the 650 except for the changes necessary to increase the bore from 68mm to 73/77mm.

The 650 Norton got it's legendary reputation for a few reasons. It was first only available to the USA, which gave it a bit of mystery in it's home market, then when it appeared for sale in the U.K. labeled as the 650ss it tested in magazines at a higher performance all around than the Triumph Bonneville. When the Atlas initially came out in the USA, then in the U.K. a year or so later, it not only had a much lower compression ratio, but was initially supplied with a single carb, so it was not aimed at the performance crowd, plus it's heavier pistons made it shake a bit more too.

Once the Atlas came out in late 62' the 650 was not marketed in the USA too much and sales were very small in comparison. Since the Atlas was not available in the U.K. until 64' the 650ss stayed at the top of the Norton range there and did really well in racing.

Dunstall and others eventually got the bugs out of the 750 and made it fly, but when the Commando came out for 1968 with improvements in it's engine for durability and a lot of marketing hype, the 650ss and 750 featherbed bikes were pushed out of the limelight and faded away.

The motorcycling enthusiasts of the early 60s never heard anything but praise for the 650ss, while the 750 Atlas had a reputation of being slower, vibrating more and having a few bugs like blowing head gaskets and weak cylinders.

So the 650 Norton was a unique package of power and handling just long enough for enthusiasts to notice it's successor's were not so well rounded in comparison. It was the high-point and flag-ship of the original Norton works which was dissolved after 1962.

Presently any 650 Norton is a rare bike. They were made in low numbers to begin with, used hard and blown up then used as raw material for the making of various specials. Any that are left intact are much harder to find top-end parts for than the later 750/850 bikes. Aside from the small bore, most any Commando upgrades/parts will fit giving similar performance and power/reliability.

Some year-by-year 650 Norton facts:

1961 - First official model year. Almost all of 1961 production sent to the USA with the bikes painted almost all blue with red seat covers, small capacity fuel tank, seat moved forwards to suit. Introduced as the "Manxman".

1962 - initial production still sent to USA in the form of all blue/red seat Manxman bikes. 99 of the first 100 650ss bikes were sent to the USA, About half of them looked identical to a Manxman except for having black seats and engines stamped 650ss above the crankcase breather, the other half were still blue but had black frames and seats. Some later 650ss bikes shipped to the usa had the small Manxman tank but the black/silver paint. First year for 650ss and ONLY year it was produced at the original Norton works, a special bike....

About 560 650 Nortons were made before 650ss production kicked in for the 1962 model year, these were the original usa Manxman bikes, by the end of 1962 a bit over 2000 650 Nortons were made at the original Norton works before they were shut down, rare bikes....

1963 - Production small due to parent company AMC abandoning the original Norton works and laying off all workers, moving production to the Matchless works. Specification very similar to 1962 models while AMC used up old Norton stocks of parts. I am not sure at this point if any of the bikes made at the original Norton works late in 1962 were manufactured as 1963 bikes, it may have happened, the Norton records hold the answers.

1964 - 650ss as previous except for many small detail changes to cut production costs. Previous satin-chromed/show chromed hardware largely eliminated for zinc/cad plating. Steering-stop welded on instead of bolt-on. fuel tank filler moved to right side of fuel tank. Smiths Chronometric instruments replaced with magnetic grey-face. Parts detail, material changes from use of new machinery, tooling and jigs too many to list. The later AMC Dominators were not any less functional than before, they were just not to as high a finish and looked a bit more like consumer goods than works of art.

1966 - Continued changes. Upper rear engine plate mounting welded in instead of through-bolted. Oiling system improved with double-speed oil pump gears, larger oilways and pressure-fed rocker arm spindles. Spigot sealing cylinder to head eliminated.

1967- onwards. Amal Concentric carbs phased into production. Head castings same yearly as Atlas and Commando just machined differently for smaller bore etc.. Last hurrah is the single-carb Mercury touring bike sold through 1970, oddly outlasting all other pre-Commando Norton models.
Last edited by beng on Sat Oct 19, 2013 6:18 am, edited 3 times in total.

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Re: The 650 Norton thread

Postby acotrel » Tue Oct 23, 2012 3:29 am

I must be old fashioned, but to my mind the Manxman was the ultimate version of the featherbed twin, and I'd much rather own one than any commando. The crankshaft in my 850 commando had a hole bored in it opposite the journals to give the silly balance factor. If you plug it with steel, it just happens to give the perfect balance factor for a high speed bike with rigidly mounted motor. The Norton works, pre Dennis Poore were not all stupid. I believe that making the 650cc motor into a 750, and then an 850 was ambitious, and Poore never got it right. He might have done better to produce two models - one for commuting, the other for high speed work. One bike with that long stroke motor cannot do both, the crank balance requirements are different in each case, and vibration is the killer.
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Re: The 650 Norton thread

Postby Triton Thrasher » Tue Oct 23, 2012 4:42 am

acotrel wrote: He might have done better to produce two models - one for commuting, the other for high speed work. One bike with that long stroke motor cannot do both, the crank balance requirements are different in each case, and vibration is the killer.


They did produce the Mercury up to 1970.

I read that somewhere...

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Re: The 650 Norton thread

Postby acotrel » Tue Oct 23, 2012 6:36 am

Are you telling me that the Mercury was an advance over the Manxman ?
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Re: The 650 Norton thread

Postby beng » Tue Oct 23, 2012 7:38 am

The single carb Mercury was not on sale until the 650ss and Atlas road bikes were being phased out.

1963 and earlier Norton did have single-carb versions of the 650 for sale though, the DeLuxe with it's enclosing bodywork and the Standard, which was supposed to be painted all grey. Both super-rare bikes, let me know if you see any laying around.

The Manxman could do double duty as it was supplied new. I put a 23-tooth gearbox sprocket on mine and it would pull it in high gear at 70mph down the limited access highways very well. Vibration did not come in until over that speed. With a smaller gearbox sprocket on the bike then you had your racing machine. The SS cam would pull on the top end as high as you wanted to rev the engine. When Cycle World put a Manxman they tested on the cover of their magazine in 1962, they said they used 8000 as a shift point during testing! I would not want to have bought that from Berliner after they were done with it.....

John Gregory and T.C. Christenson of "Hogslayer" fame started their drag-racing careers with the 650 Manxman and developed a list of performance modifications for it including swapping in Model 99 pistons, porting the intake bowl under the valve etc.. Their 650 Manxman was good for 110mph+ in the 1/4 mile drags. They also had an over-bored Atlas in street-trim that ran 92mph at the end of a 1/8 mile dirt strip.

Stretching the Norton and Matchless 650cc bikes to a 750 was not done for any good reason, my guess is pressure from the Berliner brothers in the USA so they could have something to crow about in magazine ads and tests. The Berliners sold the bulk of Norton production and put up the cash and big orders that influenced production. I have one old news article in a Magazine that tells how they had just finished up in a meeting in England sealing the deal for thousands of the Hybrid Matchless/Norton Scramblers.

But the Atlas was developed at the Bracebridge Street works. I have 750 Atlas engine #2 sitting here and it has a lower serial # than one of my 62' 88ss bikes 101xxx. But Bracebridge Street did supply the Atlas as a touring model with a single carb, the twin carb road and scrambles jobs were not sold until after AMC shut Norton down and took over.

So I agree with Acotrel that the 650 Norton was the high-point as far as a pure Norton twin roadster goes, after that everything AMC put out was sort of a compromise or trade-off made for the sake of USA dollars.

The Manxman has a special place in Norton history as the first 650 and introducing the engine for sale that all Nortons would more or less have from then on. But my favorite 650 is the 62' 650ss as supplied to the home market in the U.K., which is pretty much identical to the Manxman except it has the larger tank and the black/silver paint scheme. Though the Manxman was very good on fuel consumption with it's small 1 1/16" Amal monoblocs, I still like having the security of a larger fuel tank on highway trips.

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Re: The 650 Norton thread

Postby daveh » Tue Oct 23, 2012 8:45 am

Very interesting information, Beng. If you lined up a good, standard 650SS against a standard non-Combat 750, or an 850 Commando, how would it compare in performance terms? For example, would the Commandos pull away off the line and in top gear roll-ons? Does it feel comfortable cruising at 70mph? Just trying to get an idea of what it's like to ride.

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Re: The 650 Norton thread

Postby beng » Tue Oct 23, 2012 8:49 pm

Realistically the 650ss and Commandos all have the same engine and about the same weight, but the Commandos have a displacement advantage and in many cases a breathing advantage.

The early 650ss had very small carburettors and the 650ss had intake valves smaller than the 750. Also the first 650 Nortons had too large diameter exhaust pipes, they were 1 3/4" from beginning to end.

The very last 650ss had Commando sized carbs and better ports and there is no reason it should have run much slower than a Commando and any advantage one had may have been in the hands of whoever was keeping them tuned up.

I rode a late 73' 850 Commando for quite a few years and owned and rode some non-combat 750 Commandos, they were all faster than the stone-stock 1961 Norton Manxman I had. I don't think there are too many Brit bikes that can out-do an 850 Commando in a high-gear roll-on. There is no doubt the featherbed bike would at least hold it's own in the twisties though.

A Commando will have a better ride as it has more rear suspension travel and fits taller riders better. As long as they are tuned well for their intended use the bikes themselves are comfortable doing anything asked of them.

The legend of the 650 Norton was made in the pre-Commando days though when it's main competition were other 650cc twins which it could at least match in power and more than match in handling and braking.
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Re: The 650 Norton thread

Postby J.A.W. » Thu Nov 01, 2012 2:56 pm

I get that Britain had to focus on export earnings to the U.S. [final war loan repayment was made quite recently..] but while never as common as BSA/Triumph machines, the 650 Nortons were available in this part of the world.
As for the vaunted featherbed, there's many a Gold Star/Velocette rider who had no fear of being shown up down the highway point to point by any Norton 500 roadbike.

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Re: The 650 Norton thread

Postby beng » Fri Nov 02, 2012 6:27 am

J.A.W. wrote:I get that Britain had to focus on export earnings to the U.S. [final war loan repayment was made quite recently..] but while never as common as BSA/Triumph machines, the 650 Nortons were available in this part of the world.
As for the vaunted featherbed, there's many a Gold Star/Velocette rider who had no fear of being shown up down the highway point to point by any Norton 500 roadbike.


The total production out of Bracebridge Street for 1962 and earlier for quite a while hovered around 10,000 machines a year total, for world-wide distribution. I am not sure what Triumph/BSA total production was for every year. In 1964 a bit over 15,000 Triumphs were imported into the USA alone and in 1969 Triumph total production peaked at just under 50,000 units. BSA imports into the USA were very high also.

So the old Nortons were spread thinly over the globe. Through the 50s Norton did not really sell high-performance street bikes like Triumph and BSA purposely did. The International was a long-stroke dinosaur that was easily eclipsed by the short-stroke pushrod singles that BSA and others offered in the 1950s. So nobody did have to worry about being left behind by any standard production Norton roadster in a contest of speed. The 1962 88ss, little brother to the 650ss, was one of the best 500cc roadsters ever built, a Goldstar killer, but the game was almost over when it showed up.

It is what makes the legend, Norton with it's small size and shoe-string budget coming out in very limited numbers with some of the best all-round British roadsters ever, the SportSpecials, right before businessmen systematically make the British motorcycle industry more silly and less profitable each year.

1962 was the last golden year of British motorcycle production. All the old companies still had their identity, fantastic machines like the Goldstar, G50 and Manx etc.. were still being built, and then almost over night everything changed. The production line-up for 1963 onwards was changed and gutted for profit's sake, and the constant bankruptcies and merging erased the identities of the old factories and destroyed the moral of the workers that at one time loved their jobs.

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Re: The 650 Norton thread

Postby marinatlas » Fri Nov 02, 2012 6:43 am

Hi Ben, it was a pleasure to read .....just keep on , have a nice day, Pierre
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Re: The 650 Norton thread

Postby daveh » Fri Nov 02, 2012 7:48 am

marinatlas wrote:Hi Ben, it was a pleasure to read .....just keep on , have a nice day, Pierre


Seconded.

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Re: The 650 Norton thread

Postby acotrel » Fri Nov 02, 2012 10:41 am

I loved reading your disseration on th e Norton t wins. In about 1960 a friend of mine ran out of money in Brisbane, and rode 600cc Norton home to Melbourne in rain all the way. it took him about 14 hours to do the 1000 miles. When he got home, he fell into bed and stayed there for three days. Those old bikes were extremely reliable. I don't think that could have been done with a Triumph twin of that era.
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Re: The 650 Norton thread

Postby Triton Thrasher » Fri Nov 02, 2012 11:00 am

acotrel wrote: I don't think that could have been done with a Triumph twin of that era.


Why- what's the difference?

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Re: The 650 Norton thread

Postby J.A.W. » Fri Nov 02, 2012 2:05 pm

As a teenager,I passed my practical licence test on a mate`s Dominator 88, the examiner cop never questioned the capacity [nominal 250cc limit for provisional licenced riders then]- but did make comment on the Norton being a "real riders bike"..

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Re: The 650 Norton thread

Postby BA10BOON » Wed Nov 21, 2012 9:03 am

marinatlas wrote:Hi Ben, it was a pleasure to read .....just keep on , have a nice day, Pierre


+1. Very interesting indeed. 8)

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