Commando Top Speed? (2010)

Its very very easy to post BS on chat forums, but very much harder to back this up with anything even vaguely resembling fact!
Trouble is with this sort of rubbish, is that those that dont know better tend to believe it, so in some cases yet another urban myth comes into being.

In threads concerning top speed, in general it seems that any requirement to have rear wheel BHP figures that are related to the speed claimed, is something that is entirely irrelevant! In the real world any reasonable 10 yr old Jap 600 four will eat something like a Commando alive, both in terms of performance and handling.

Something that seems to be entirely forgotten by some people posting in regard to older classic bikes such as the Commando, is that these are vintage machines, and as such its pretty silly carrying out extensive modifications, which in some cases seem to be designed to make them perform more like a modern machine.

In real terms its very very difficult to make an old classic bike perform anything like a modern bike, so why not just enjoy as is, and simply change very poor OE parts such as carbs and ignition, which makes the bikes nicer to ride and much more reliable?

One of the things that attracted me to the Commando is that it represents a challenge to get it to perform to its optimum. Commandos have bags of potential but any number of factors have meant that only a minority ride and perform as they should. People were modifying Commandos since the factory began making them and they haven't stopped. Why should they? If they could have fitted 4-valve heads and EFI back in the day, they would have. I've had a lot of fun over the years making or watching people I know make a variety of bikes go faster. In the mid-1980s, a friend of mine even tuned an AJS 'Lightweight' 350. I sprinted it (and got real times and speeds) and we got a lot of satisfaction and enjoyment out of it.

No-one here disputes that a street Commando can't live with modern bikes except under special conditions. That wouldn't stop me from squeezing another 10 hp out of my bike if I could justify the cost! I already have my shopping list...

Carbonfibre wrote;

classic bikes such as the Commando, is that these are vintage machines, and as such its pretty silly carrying out extensive modifications

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I'm therefore very, very, very silly! But I am very happy as well!

Certainly its a challenge to get an old Norton to perform at its best, and this can be enjoyable to do. In pursuit of this though, it seems some posters here simply discount the basics such as carb, ignition, exhaust, cam timing etc, go straight ahead with very costly and involved modifications, that may well not have the desired effect.

daveh said:

If they could have fitted 4-valve heads and EFI back in the day, they would have.

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I suppose you have heard of the Piper 4 valve heads for the Commando ?

Don't know anything about them, but one of the books on Nortons has a pic of one of them, with the comment that when the factory tested it, they used valve springs that were too strong, and didn't get very good results .

Anyone know any more of them ?

When someone tried a 4 valve version of the head for a Manx, they supposedly got another 10 hp out of it, which is a lot when they only produced 50 bhp back then (Its a 500cc) . Civilisation will be dead before folks stop trying to get more hp of Manxes ?, whose only purpose in life was to race after all, and which class is still going strong...

Carbonfibre said:

Its very very easy to post BS on chat forums, but very much harder to back this up with anything even vaguely resembling fact!
Trouble is with this sort of rubbish, is that those that dont know better tend to believe it, so in some cases yet another urban myth comes into being.

In threads concerning top speed, in general it seems that any requirement to have rear wheel BHP figures that are related to the speed claimed, is something that is entirely irrelevant! In the real world any reasonable 10 yr old Jap 600 four will eat something like a Commando alive, both in terms of performance and handling.

Something that seems to be entirely forgotten by some people posting in regard to older classic bikes such as the Commando, is that these are vintage machines, and as such its pretty silly carrying out extensive modifications, which in some cases seem to be designed to make them perform more like a modern machine.

In real terms its very very difficult to make an old classic bike perform anything like a modern bike, so why not just enjoy as is, and simply change very poor OE parts such as carbs and ignition, which makes the bikes nicer to ride and much more reliable?

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A very hearty +1 Make them look good, sculpt them to your style or liking, but expect them to equal or better even a smaller displacement modern bike, no way.

Jean

Rohan said:

I suppose you have heard of the Piper 4 valve heads for the Commando ?

When someone tried a 4-valve version of the head for a Manx, they supposedly got another 10 hp out of it, which is a lot when they only produced 50 bhp back then (Its a 500cc) . Civilisation will be dead before folks stop trying to get more hp of Manxes ?, whose only purpose in life was to race after all, and which class is still going strong...

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Never heard of the Piper heads for Commandos. I would have thought that you would need to get the engine to rev more safely to exploit the greater performance potential of a 4-valve head. I guess a pushrod design would also not be ideal for this purpose either. Maybe some experienced engine tuners will chime in here.

Syd Mullarney produced a 4-valve head for the Manx, and Bob Newby raced the bike. He is of course known to Norton riders for his belt drive conversions. The legendary Joe Ryan Manx Norton, which was raced in Irish road races with such success in the 70s and 80s by Sam McClements, was reputed to be an ex-GP bike with a 4-valve head. The stewards ordered the bike to be stripped to measure the capacity after one race because the bike was so fast and Joe Ryan was seen covering the head in a towel as he removed it. I remember this bike embarrassing big Suzukis, Hondas and Tridents in open class road races and getting podiums before classic racing was established.

Hi
Piper 4 valve heads
Speak to Les Emery at fairspares.
On E Bay you will occasionally see him selling a 4 valve piston.
The head was developed by Pete Lovell (the man) as standard it did not add anything to a stock bike. After Petes work it added in all areas. However not enough for the money & imagine a breadbin (or a house brick) stuck on a set of Commando barrels & you will get an idea of what it looked like!
ie it was a test bed with no styling influence.
I dare say Les will sell you one.
all the best Chris

Its very easy to get an old motor to rev much faster, either by more efficient induction and exhaust systems, or by forced induction. However its even easier to get them to blow up, and this was something that was found to be the case time and time again, when old Brit twins were being used for drag racing back in the 1960s.

When the 4 valve head was tested way back it was supposed to put out 90 hsp and to have pulled the spokes out of the rear wheel - totaling the bike.

If anyone is interested in spending a fortune to have one made - give me a PM.

I believe Andy Molnar now owns the rights and tooling for the Piper 8-valve heads. IIRC he bought them from Les some years ago. The article below is from a Classic Bike article some year back. I have the full article, with pictures of the head on a Commando and test ride comments, but only in .pdf forrmat. I haven't found a way to post .pdf files here. Photobucket doesn't accept them.



Ken

All the talk has been on getting more power yet no one mentions anything about going lightweight, what is the power to weight gained by Ludwig on his 300 lb street Commando? and being european, he is probably not full of cheeseburgers which further tilts the ratio in his favor. Power gain is cool, but weight loss may be even better not only for acceleration, but for handling too.

Hobot, that is one thing you have on many of us including me, you look rail thin, I can just picture you flapping in the breeze hanging by your tall handlebars at 150+ :wink:

Jean

Jean I've always been skinny but more so last few years, not sure why 'cept I eat a couple time a day but my metabolism eats 4 times a day. I'm barely 150 now, was 165 five yr ago.

I have given some attention to weight loss in Ms Peel, rocker arms to wheels but that mainly helps to lift back up, not much effect on top speed except the time to run up to it. Ms Peel may approach Ludwigs feather weight in her most minimalist non road legal or practical version for hill climbs or trials set up w/o blower and support systems. Her hp/wt ratio improved with Drouin and other stuff, but then more to pick up, ugh. Unless trying to play with 900's above nearly 140 mph in opens I may not even like the Drouin excess.

4.5 lb wt lost is said to = 1 hp in acceleration. 450 lb Cdo minus 150 lb is worth
like 33+ hp gain. Do ya know how much 33 hp extra in a Commando costs? About as much as removing 150 lb worth. But again this only helps acceleration not top speed against wind and internal friction. Many land speeders are pretty heavy on purpose for gravity aid to keep em down and planted plus strong enough to take a fall down roll over.

Cleaver aim of exhaust plume and fairing pieces and plates or deflectors may give more top end pay back than anything. There is a miles long down off Ozark Plateau straight hwy about 40 miles from me that a fella got a ticket for 178 mph. Even if I could I'd have to ask myself - really how lucky do I feel punk?

Ken, thanks for posting that article on the 4-valve head. I had no idea it made that much difference in the mid-range.

Jean, yes, 'adding lightness' is the alternative way to make a Commando quicker, as Ludwig has so ably demonstrated.

ludwig said:

http://www.youtube.com/watch?v=lzwvfUXz3eM

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I have that LP of the Safaris :!:

That road looks like a long version of one of my favorites for the Superduke. Seems too fast going down but all kinds of fun going up without the noise of tire chatter on the brakes. Full lean and lots of transition with tires screaming for traction.

I weigh 210lbs and don`t flap in the breeze much at speed even at 140mph :wink:

Off to get another rum
PS.
Big thaw this weekend saw for lots of sliding and drifting before having to wash the salt off. Not enough traction for top speed runs. :lol:

Opps hobot and world was mislead by them NewZealand zealots on top speed.

On 1/3/2011 10:19 AM, norman@normanwhite.co.uk wrote:
> Hello. My John Player Norton,its and my history(former factory Norton and Honda teamster) I think you may be aware of already.(my desperately outdated web site http://www.normanwhite.co.uk ) I have raced the machine since 1997,and recorded 55 wins and 4 championships. Often I am invited to compete or demonstrate at different venues mostly in Europe,and noteably in New Zealand. At a race meeting in Mugello Italy some years ago I was invited by the Italian hosts to race at their international race meeting. This circuit is extremely fast,I believe the modern Moto GP machines exceed 210mph,and I finished 3rd in my event. My hosts claimed my machine reached 171mph ,recorded by their electronic timing gear. Somehow this info found its way into some publications. I am almost certain my machine did not reach this speed, as the gearing we selected for the race would by our calculations achieve a speed of 156mph at 7800 rpm.,some 15mph slower than published. Must admit I never disputed it though. Got quite a thrill out of it actually! Best wishes,Norman White.

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According to SCTA's website, the top speed recorded by a norton is:

MPS-PBG J. Smith Norton ' 99 148.981 (running in the 1000cc class)

Curious; I know it must be goofy, because I downloaded the entire record list and that's the ONLY Norton listed!

grandpaul said:

According to SCTA's website, the top speed recorded by a norton is:

MPS-PBG J. Smith Norton ' 99 148.981

Curious; I know it must be goofy, because I downloaded the entire record list and that's the ONLY Norton listed!

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It's also the only one I've found in the SCTA records. The other Norton records, including the ones just set this year by the "new" Commandos, are in the AMA record book. You can find them through the end of 2009 here

http://www.speedtrialsbybub.com/2010_ev ... s-2010.pdf

They are at the end of the rules book. The records for 2010 haven't been added to the rule book yet, but you can find them listed here

http://www.speedtrialsbybub.com/2010_ev ... lts10.html

All the AMA records since the first BUB meet in 2004 were set at the BUB events, which are sanctioned by the AMA, not the SCTA. Quite a few bikers are now running at the BUB event, in part because it is bikes only. The SCTA events are for bikes and cars. Fred Eiker's 155+ mph run at the SCTA World Finals in 2010 is not in the record book because he tied the existing record, but didn't exceed it, so the old record still stands.

Way back when, SCTA and AMA had common records. Somewhere around 1978 the AMA got out of the landspeed record business, and left it to the SCTA. In 2004, when Dennis Manning started the BUB meets, he convinced AMA to sanction the events, so in the AMA record book there is a gap between 1978 and 2004.

FWIW, that record by J. Smith was set with a Commando 850 running a turbocharger. The engine looked pretty stock to me when I saw it at an El Mirage meet in 2001 or thereabouts. Unfortunately, he took the bike out for a run after the course was shut down, crashed, and died. It was speculated that he'd run off the course and encountered pot holes. The course markers had already been taken down, and it's pretty easy to get off the smooth course without them for reference.

Ken

daveh said:

Ken, thanks for posting that article on the 4-valve head. I had no idea it made that much difference in the mid-range.

Jean, yes, 'adding lightness' is the alternative way to make a Commando quicker, as Ludwig has so ably demonstrated.

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The 4 valve head improved the midrange because the cam timing and port sizes are correct for high effeciancy at mid RPM. What the added flow capability at low lifts from a 4 valve head does is it broadens the powerband so the engine tuned for mirange still makes good high rpm power. If you take a 4 valve engine and use cam timing specs from a hot 2 valve engine then you end up with a flat midrange just like the two valve engine but a larger increase in high rpm than you would get with two valves.

Likely the best ways of increasing performance on a Norton are "adding lightness" or forced induction.

Cutting weight is a winner all around until parts start falling off.

Forced induction allows you to make more power without increasing RPM. A longstroke Norton motor will handle an increase in torque from a blower much better than it will handle higher RPM. Just keep the boost low and don't expect a big gain. You still won't be able to keep up with a modern crotch rocket if you want it to stay together more than a few miles. As boost goes up heat becomes a problem. Even if you build it to stay together with a lot of boost it will only be good for sprint races as it will not be able to dissipate heat fast enough to keep up with a modern rocket for very far. Jim

ludwig said:

A reasonably fit person can produce about 1 ( one ) HP , but huge torque .
See what 1HP can do :
http://www.youtube.com/watch?v=lzwvfUXz3eM
I see lots of these guys in the Alps , and the good ones are not easy to catch up .
I know this particular road well .
Does anyone here who rides a std Commando with std brakes , thinks he can go downhill faster ? .
I suppose if you ride well , you can , but it won't be easy !

Why are these cyclists so fast ?
Ridgid frames , skinny tyres , high riding position ..
I believe the answer is weight .
That's why I don't try to get more hp out of that poor old engine , but spend my time and money on shedding weight , brakes , suspension ..
It won't increase top speed , but in the mountains it makes all the difference ..

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I ride bicycles a lot and getting one HP from a human is only done at a young age and helped a bit (OK, a LOT) with chemicals, most recreational cyclists can make 150 to 200 watts which is a long ways from one HP (745 watts) Top cyclists can make more than one HP for a brief period (seconds).

Going downhill does not require any power, just balls and they go fast because they use ALL the road, a car under the same conditions (no power) can't keep up and a motorcycle probably could not, but using the engine to accelerate after a turn, either could pass the bicycle (assuming they could use all the road too). A motor vehicule going downhill without any power can easily exceed 120 Kph, that is very difficult if not impossible to do on a bicycle. A standard Norton could not keep up, the brakes are too weak and would turn to mush after a very short while.

Adding lightness helps everywhere on a Norton, accelerate and stop faster.


Jean