Available engine performance

Fast Eddie said:

Errr, no, you most definitely do not wanna do that !

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The theory is that big is better. Once the Commando inlet ports are over-size, the head is stuffed. The rev limiit is 7000 RPM, pretty much regardless of whatever else you do.

The guy who used to own my Seeley frame had a 750cc Laverda motor in it. When I told him I was fitting the 850 Commando motor, he told me something interesting. He used to work for S.R.Evans in Melbourne doing pre-delivery on Commandos and H1 and H2 Kawasaki two -strokes. The guys used to road test the bikes by taking them to the Richmond Boulevard and giving them a good thrashing. The Commandos were right up there with the Kawasakis. When I was racing, I saw one of my mates get on the gas too early with an H2 Kawasaki - he got shot up the track like a stone out of a shanghai. They had 5 gears and were extremely fast. For road use, a standard Norton Commando is probably fast enough for anyone. Modern bikes are faster, but where can you really use them ? Even if you got into a situation which needed a lot of speed, you would not need to grab a handful of throttle too fast. Most guys who do not race, probably do not think quickly enough for a modern bike.

acotrel said:

Most guys who do not race, probably do not think quickly enough for a modern bike.

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Does that mean guys ride Nortons on the race track because they are slow thinkers.

Of course it does.... Most of us have been devoutly keeping an outdated and worn out design chugging along when there's new sophisticated machines available.... Not so much slow thinking but definitely resistant to change.

My old Norton is still in the garage and all the modern machines are gone. My thinking is considerably slower than it was a mere 15 minutes ago, but I have being delusional working for me. Can't beat that.

Schwany said:

Does that mean guys ride Nortons on the race track because they are slow thinkers.

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Yep, that's me....still doing what I was doing in 1980!

jbruney said:

Of course it does.... Most of us have been devoutly keeping an outdated and worn out design chugging along when there's new sophisticated machines available.... Not so much slow thinking but definitely resistant to change.

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When I returned to the race track with a motorcycle I used a GSXR750SRAD....It used to rattle my eyeballs in the sockets and I struggled to keep the front down with only twice the rwhp my Norton has!

It was fun but on most track days guys on GSXR1000s and R1s with another say 40hp to play with just got in the way when it got twisty.

I just wouldn't go there, very few tracks I would ever get to ride are suitable for running one of those, or it's successors to its limits without the sharpest mind and reactions.

Actually when I started racing again at about 58 I ran a GSXR750F, with only 1.5 times the rwhp of the Norton, it was a comfy armchair!

I enjoyed the Suzukis whilst they lasted, but as an old guy I am so much happier exercising my slow mind on the Norton.

Re cams; a stock cam is good enough for street use, just time the lobes with a large timing disc and reject any that are more than a couple of degrees out from sepc.
On getting extra acceleration, inlet port work and polishing is the cheapest way to go, despite the naysayers who say it doesn't work. Opening the port past the valve guide can help to give that " ram air effect" but do not open up the port from the carb manifold to the valve guide other than to remove the rough casting - just enought to smoth & polish it , keep it at 27.5 to 28mm there. You'll gain up to a whole bike length from a standing start against a equivalent bike, as well as getting quicker on throttle roll on, roll off, roll on.
And now for something really free, fit 2 small funnels somewhere up front connect half inch bore hose pipe to just inside carb bellmouth.
You will not feel any effect until 60 mph then if you roll the throttle on- off- on yo will feel a few more gee - gees there.
Disclaimer; it's your responsibility to check the gas/air mixture is correct by doing a plug chop at 65 mph, but generally it's usally OK.
Also works on other normally aspirated fuel guzzing 4 stroke engines, diesels, the bigger the engine the bigger the increase in performance.

Seeley920 said:

Ah Ted, that brings back memories

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For me too. I was born and bred not to far from his shop. That small area of Leytonstone High Road was a bikers mecca in the 60's 70's & 80's. MCS, Rivetts, Read brothers (Read Titan) all a spit away from each other and I'm sure there was another shop very close but I don't remember the name. Me, my brother and mates used to be regulars on a Saturday afternoon as there was always something of interest to bike mad teenagers. Ted Bloomfield was a great guy and had some real unobtanium stuff in his shop. I can vividly remember the genuine chrome wire Triumph 650 Trophy and sparkly glass fibre TR25 exhaust guards hanging in his window for years. Later on I used to pop in for a chat and pick up a copy of Old Bike Mart on my way home from work and put a quid in the dog charity tin, but it was difficult to talk to him for long as he was continually getting phone calls from all over the world from folks looking for parts. Last I heard he wasn't well and sold the business to one of his employees, then some time later passed away. His Brother Ron also had a shop called Bloomfields in Portway Forest Gate, East London. For some time he had the actual green show Bandit in his window. He became a Suzuki specialist, and a few year ago I called them for a part. It was Ron who answered and I mentioned the Bandit in passing. You've got a good memory he said, that was all of 35 years ago !!

ludwig said:

Instead of searching for more hp , I kept the engine of my Commando standard ( sort of..) and focused on reliability, weight reduction, brakes, suspension, etc..
For more than ten years now (not last year) we have a 3-day meeting somewhere in the Alps, friends from diff. parts of Europe who share the same love for the mountains.
I am the only one with an 'old' bike.
At the start of our first ride out, They asked me if I was sure to join them, because they had no intention to slow down or wait for me to catch up.

They don’t ask that anymore..

L-R : Triumph, Norton, Ducati, Kawasaki, Honda, Triumph, Kawasaki.

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Sorry Ludwig, but this has to be said - Ecky Thump !!

I have only ever ridden one normal Commando, and it seemed fast enough. It depends on what you want in a road bike. I find riding motorcycles on public roads extremely frustrating. and dangerous.
Ashleigh suggested I should put my Seeley 850 to road use. Doing that would drive me crazy. First gear would result in me losing my licence. I rode on public roads until I was 29, then went racing - racing is safer. Very few guys do anything stupid during a road race. Your brain adjusts and the speeds mean nothing, unless you are too slow.

cliffa said:

For me too. I was born and bred not to far from his shop. That small area of Leytonstone High Road was a bikers mecca in the 60's 70's & 80's. MCS, Rivetts, Read brothers (Read Titan) all a spit away from each other and I'm sure there was another shop very close but I don't remember the name. Me, my brother and mates used to be regulars on a Saturday afternoon as there was always something of interest to bike mad teenagers. Ted Bloomfield was a great guy and had some real unobtanium stuff in his shop. I can vividly remember the genuine chrome wire Triumph 650 Trophy and sparkly glass fibre TR25 exhaust guards hanging in his window for years. Later on I used to pop in for a chat and pick up a copy of Old Bike Mart on my way home from work and put a quid in the dog charity tin, but it was difficult to talk to him for long as he was continually getting phone calls from all over the world from folks looking for parts. Last I heard he wasn't well and sold the business to one of his employees, then some time later passed away. His Brother Ron also had a shop called Bloomfields in Portway Forest Gate, East London. For some time he had the actual green show Bandit in his window. He became a Suzuki specialist, and a few year ago I called them for a part. It was Ron who answered and I mentioned the Bandit in passing. You've got a good memory he said, that was all of 35 years ago !!

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Last I heard Ted was in heaven still selling the very last Goldie conrod in the world!!!
So did you used to go to Dougy Clarke's at Arnos grove?

acotrel said:

I have only ever ridden one normal Commando, and it seemed fast enough. It depends on what you want in a road bike. I find riding motorcycles on public roads extremely frustrating.

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Horses for courses Al
Driving cars on public roads is also extremely frustrating (for me anyway)

baz said:

Last I heard Ted was in heaven still selling the very last Goldie conrod in the world!!!
So did you used to go to Dougy Clarke's at Arnos grove?

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No, Arnos Grove is "Norf Lonon", so was alien territory for me.

cliffa said:

No, Arnos Grove is "Norf Lonon", so was alien territory for me.

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If you think Ted had some political views you should have met Dougy !!!!!

baz said:

If you think Ted had some political views you should have met Dougy !!!!!

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Very different times.

Schwany said:

By the way, "accelerate as quick" is relative. It's only a 750 Norton. Only way it would really be fast is if dropped out of a C17 Globemaster from about 3000 feet.

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What is the terminal velocity of an unladden Norton? Roadster or Interstate?

Peavey Jeltz said:

What is the terminal velocity of an unladden Norton? Roadster or Interstate?

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Maybe 3000 feet isn't high enough as a starting point. I was figuring it would be at least faster than a 750 on the road. Most of them didn't go much faster than 120mph. Motorcyclist should have listed the terminal velocity.

Thats for the INTAKE MANIFOLDS . If the passge is regular in contuors , the ram effect is better. undisrupted .
32 concentrics are gunna constric it , Theres better refined instruments availabe . Even horrible jap ones , .

Tapering the head passages , conical ( V shallow ) flared outa the bend to the seat . Valve Head / Seat NIL RECESSION .
If the heads IN the chamber its unmasked *& utilises the full lift ( Rather than say 1 mm recession on 9 mm lift is over 10 %
loss of circumfential hight ( lift ) At the valve face . Oversize valves may save original seats , allowing ' the flare ' for better distribution .

All most important . Seen plenty of professionally ruined heads . Particularly pommy motorsickle ones . 1/8 oversize intakes are fine .
High Comps gunna make it crankier .

If you want it cranky , try the Combat Cam . Tho the 4S is the same lift curvewith meat off the heel for broadened pattern .
3 S was the peaky ( top end ) one .Std. Commando cam is a old Dommie ' S S ' grind . So pretty good . Will wind right out .

Was a 5 600 or 5 800 Max CONTINUOUS in Poores 850 days . & 200 Max. Ever . 7 500 in 1970 blowing off everything ,
and overhauling each second meeting . A Impulse ( VDO / Krober etc ) Tacho is a must if giving it grief . Maybe a Elec, cut out
like wot stops the modern sh*t grenadeing . A good stock Combat'd rev to 8 000 . A good few times . tThen B A N G .

A Z1 . ? . a good target . On the 40 over 650 Bonnie . But It'd rev to snot . Come on the pipes at 7 500 , cruising .
or around 3 / 3 500 , hot & w f o . ( 7 500 was 93 in third & it'd run another 1 000 ). Both pulled up about as appallingly .
Id imagine the ton on dirt roads wasnt the Z1s thing either , Smmoth surface & the Bonnie'd be ' hands off ' o.k. .

Some twit had a excess 11 He'd raced . 4-1 onit . From Hallidays firrst go I had a wheel to 80 , 2 nd was the other way .
4 p.m. friday the universe implodes past that , in town .

A Commando , tight , can be thrown into usual 45 corners at 60 , in 2 nd . on the high gearig . Drift / Powerslide .
XSes slide on their side , Z1s'd spit you off if you tried to drift through between straights , on the throttle . Lettalone if you Backed Off .

BUT , a Commandos skittish , sub par chassis in comparison ( tube diameter etc & fork tube Dia . etc ) in Comparison to Laverda ,
Ducati , Rickmann & Seeley .Not that any Jap sh*tter was any better till 80 odd . And dontmention a GS 750 . On the dirt , either .
Pogo Stick ? going hard .

So a tweaked Rickman or Sealeet ( Full Loop Frame ) 'd be BETTER . No Question .



Any idiot can see thats not a ' unit ' ( engine ) frame . though some dont .

Looks Better Balanced .

SO , it comes to makeing the most of whatcher Got .
CONTROL OIL TEMPERATURE . Its Oil Cooled TOO .
Like this modern trash .

DONT OVER REV IT . Never past 7 200 Ever . Not ONCE !
So get a accurate instantaeneous tacho .

Make sure the gearbox wont fall out ! a steel tube at the lower bolt wouldnt hurt .

A masterpiece was a third Iso UNDER the gearbox shaft . TOTAL alters the Force manadgement
and load paths , Gets it to hook up on the dirt roads , without the steering head being overstressed .
As the top tube becomes more a lateral torsional restraint , cranked over . And its adequate for that .

The cradle being then the prime triangulated area , the downtubes are likely then more efficent too .

Just leaves the swing arm pivot ( Cotter It ) and the shitty axles . What grade steel are they stock ? ? .



Something after this fassion is common on factory Triumph 50s & 60s U.S. Comp. Spec. equipment .

I ran 2 way damped Girling Gas Shocks with 110 Lb Springs . Wish I hadem on the Bonnie .
The back pummped down in undulations at 80 , cranked over , Still. It pulled up cranked over in a blind sweeper
from 60 to 5 mph , crawling logging truck . Two Up . Both were more stable two up . Unless the pillion was mentally defective ,

Vs XS 11 was 8.75 : 1 C.R. , which was plenty . Stock cam then . Previously Combat . Ran the W& s Springs ( Same as JoMo Triumph in the 50s / 70s )
With the 2S Combat , stuttered at 3 200 , 3 500 it was ' on ' . From 4 000 W F O , it howled . Hooked up & threw itself at the horizon . Much less fraught
With the std cam . But in effect , on the street , you could pass as a civilian instead of a interloper . Odd to see the entire motorway clear the right lane ,
for more than a mile ahead , upon its entry .

Commando was Cycles ' Mounytain Road ' King . Unassailed , in a test of ten . So the Chassis comments need to be taken in context . The under Iso is a winner though . and fairly simple mod .

You need suitable coils , mounted in a breeze, that wont fade under duress . Some people can even get the late 6Ca points to operate accurately . Their high maintanance and fret your nerves tho .

Fancey braided Oil & brake lines would be definately justifieable . As are braided nylon fuel lines . Unbraded can be fatal , a leak and your shot , down / up . In Flames .
Feet furver back & seat lower'd be good , later'd need a new frame .

So , Basically , their pretty good stock. For the price . Not to say a few extra pennies couldnt be well spent .

Think thats a 850 at the left , one an Aus. Mod. Prod. series against all the whizz bangs .

Recons in the 6 hour if it hadnt spat the pads out , it wouldnt have lost 7 or 8 laps more than the winners ahead .
But Ifs aint so's.

One Here https://www.accessnorton.com/NortonCommando/available-engine-performance.33255/page-7 would hold its own , then . under ' favourable conditions '
Cool Day , Word was he'd beat em , if it was any damp . Home Track & he could drift it . As per Williams . or better . Wouldnt swear by his finesse tho .
First time I saw it was Crown Lynn circuit / New Lynn . 77 or 78 . Running ( weaveing ) third . Undulateing circuit . No lack of bravery but resembled ' hung out in the breeze '
which is counter productive , fast . Came in clanking like a cement mixer . An old one . Sounded as if the cam folowers were about to jump ship . Could be said to be a bit agricultural .

Kept under 6 000 theve been known to run 100.000 miles , with good filters .

check out this sucker . The P R Headers tauck further up & in . protrudeing side stand bracket a w o l . to fit .
less windage , rider tucked in . Folding footrests'd be good . You can make half the stuff, 1 7/8 plug in headers 'd be loud and deep . 'S' type set up R & L , high . or T T Dirt , under .
If they aint chokeing it , they aint slowing it down . The Traffic Dept. might mistake it for a Spitfire overhead . I had a pointsman hold the Traffic for me on the Triton , Dual open pipes
down low on the right .