The 650 Norton thread

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You need to experiment with them, with the engine running, to eventually get the best height settings,
along with the mixture screws, to give a good smooth consistent idle.

This also involves setting the throttle cables so it neatly lifts both slides at the same time.
Synchronising the throttles, very important for good running.

While you can take a stab at the settings before starting the engine - and hope that it starts ! -
it all really needs to be done with the engine running.
Don't forget too that the engine needs to be warmed up for the best settings.

It is all a bit of a juggling act.
Don't gas yourself in the basement doing this either...
If it is legal to go for a spin around the block trying out various settings, this gives a good measure of how things are going - not stalling when you pull in the clutch to stop, etc.
hth
 
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acotrel said:
Are you telling me that the Mercury was an advance over the Manxman ?

The Mercury was made from parts for the atlas and 650ss. and was built to use up old stock parts laying around, where has the Manxman had parts made for it, that was not in any of the other Norton twins parts manual has the Norton Manxman had its own parts manual
 
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annajeannette said:
and was built to use up old stock parts laying around,

Didn't someone say that about the hybrids ?
And given that more than 8000 were made, thats quite some stack/mountain/warehouses of stray hybrid parts. !!

Mercuries might be in the same category ?
They made several thousand, was it ? Or 1500 anyway.
So would have had to order quite a LOT of parts to build all those bikes...
 
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I think that the Mercury was intended as a cheaper, more practical everyday bike,than the 650SS. Cheaper because of the lack of chrome, (primary drive cover and chainguard) and single carb. More practical by the use of a single carb, way back then lots of people were put off by twin 'tooters.
They may have used up their paint pots full of daggy blue paint as well, but that's possibly a bit subjective!
cheers
wakeup
 
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wakeup said:
I think that the Mercury was intended as a cheaper, more practical everyday bike,than the 650SS.

It had to be less expensive in the showroom than the Commando, which was being made at the same time.
 
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One cautionary note, as I found this problem while riding my company-provided 650SS. The carburator slides are hand lapped to their individual bodies. They are NOT interchangeable between the carbs. If you've had both carbs apart without keeping track of which slide goes with which body, check for free movement by sliding them through their full travel to be sure they don't stick. One carb stuck wide open when you're trying to stop is exciting, but not fun!
 
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norton_rider said:
Hi everyone, gonna do the first start up on the new carbs with the 650ss at weekend

quick question regarding setting the throttle stop screws for idle,

do you go in with them till you just see the slide move ever so slightly



or best going in all the way then back out a turn got about 1.5 turns of effect on the slide with them

premier concentrics

The horizontal pilot mixture screws are the ones you screw all the way in, then back out a turn and a half, as a starting point before you adjust them for best idle on a warm engine, as already said.

Screw the throttle stop screws in (upward) until they just touch the slides, then give them another full turn. Once the engine is warm, adjust them to the idle speed you want. You'll probably screw them in further than that first turn.
 
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Just thought I'd bring this back with it being 650ss specific has anyone ever came across plain rocker spindles without the flats on the later 650ss bikes :) very curious on that
 
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Most know there are either scrolls for low pressure systems and plain shafts for high pressure systems.
A plain shaft with only a drilled hole ( of course it would point away from the ball end) would have to be an incredibly bad design destined to kill the expensive rockers.
The flats increase the linear oil access to the shaft by hundreds .
 
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Wouldn't catch those in my engines...
I have discovered another aftermarket brand of plain shaft WITH the flat, yet the puller threads are not CEI, and are tool steel hard but crappy and you can not put the threaded bolt required to pull them without ruining the bolts. A carbide tap would be needed to chase the threads so they could then be removed with out sacrificing a bolt for each ones extraction...
These go on the wall of shame with the other garbage.
 
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Would be helpful if someone could make up some rocker spindles 50 thou longer to allow the owner to grind off the end in cases where they have worked themselves in a bit. I think I will grind some scrolls part way down to get oil to the bushes.
 
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Actually got the definitive answer on them today Norton did them before they put the flats on when they first went to high pressure oil feed :) so most likely the originals in my bike.
 
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There is also the possibility, as the bike is around 50 years old, someone took out the rocker shafts from an older iron head and installed them into the downdraught ally head- maybe these earlier rockers were shorter?
 
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Hi mate 110% they are the 66/67 hp spindles before they machined the flats onto them original spindles from back in the day. I actually got mine of the original owner so know exactly what was done etc. Got the info from a trusted Norton Yoda regarding the spindles when Norton first tried the HP system but didn't have it quite right. Hence why the manual is even a missprint on rocker spindle direction.
 
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Now all this time Benge as been calling me a idiot over the Norton Manxman 650 I said back in 2006 that the Norton Manxman has a special place in motorcycling history Now hes telling every one the same as I have, And I just happen to have a copy of the factory records for Norton Manxman and some of the last Mercury's but both were not marketed as sports motorcycle the Manxman 650 was marketed as a Cruiser for long distant miles the Mercury was marketed as a every day motorcycle or a bike with a sidecars sometimes Now the Norton Atlas was built from April 20th 1962 on and had low compression pistons with a single mono bloc 376/294 and was a long distance motorcycle with grunt low down and good for sidecars owners at the time. your pure sports bike was the 650ss that how the home market wanted it, as the cafe-racer era had long since started and in early 1961 Norton only had for its home market the model 88 and 99 later by April 1961 the 88and 99ss version but you could go a buy a 650 Triumph for less then the Model 88, So Norton owners where knocking on the Bracebridges door wanting a 650 but they had to wait until near end of 1961 for the first of the 650ss then later the Deluxe and standard use by sidecar owners at the time from the off the 650 was raced and proved it self a legend but for me I rode most Norton's And there all good to ride but the Norton Manxman 650 stand out of the crowd and its a pace of art and very good to ride at speed response well at 80 and over and found to be some what reliable to date I have some 60 or so thats come to light my one was built in December 1960 and there is the very first one now being restored to a high standard witch I think he be around 3 years to get this machine done he is now looking for down pipes and silencers if anyone know of some going spare see the YOU TUBE Threads
 
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I have a 500 Dommi engine, based on an 88 crankcase. Offset crank, alloy barrel and (why this thread) a 650SS head. I have Amal TT's on it, I am toying with changing to Keihin CR smoothbores (for the right price). Not sure yet, but my question is what is the biggest carb that would fit. I just want to know a not go above size. This is a race engine. I am thinking probably 30mm max. I know bigger is not always better, I like Keihins, I know my way around them.
 
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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.

Norton Manxman downpipes are 1.5/8ths full bore and shaped to fit the frame line so it fits to the silencers which have large welded triangle mounting bracket on top of the special silencer, so the pipes have to be right to fit,
 
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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.



Norton production from 1959 to 1960 was 8800 a year and struggling with these figures were as BSA and Triumph did 15 motorcycles to one Norton and Norton struggled to build 180 a week at that, and would build models in small batch until the parts ran out, they have 15 days holiday a year mostly in Blackpool
 
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