certified quarter-mile time.

worntorn said:

I think some of the variation in 1/4 mile times comes from reaction time and the timing method used.

The British seem to prefer the rolling start which takes the riders reaction time out of the equation.
Some motorcycle mags back in the day adjusted times by removing reaction time, so these times are the equivalent to a rolling start.

Riders taking their bikes to a North Americam strip where reaction time becomes part of the 1/4 mile will never match the rolling start or "adjusted" 1/4 mile times the magazines often used.

I suspect that this is still done as the Drag Times listed strip times for many modern bikes (stockers) always seem to be greater than Magazine test times for the same model.


By removing the variable that is the starting reaction time of the rider, the rolling start or adjusted start is really a better way to make a comparison between bikes.

Glen

Click to expand...

How the timing lights might work if drag races are run using "rolling starts" is something you might like to explain?

Rohan said:

Carbonfibre said:

The fact that the specially built Norton 1/4 bikes were using 12.5:1 compression and alcohol fuel, meant they were far quicker than a stocker, but would have almost certainly blown up if they had been used for anything other than a few 1/4 mile runs.

Click to expand...

Strange that - bikes built purely as drag bikes usually only get used as drag bikes.
Hogslayer probably wouldn't go too well ridden to the corner store to get some cornflakes.

Most of the test bikes were given to the press to test, so how does that work ?

Click to expand...

Point here being the times posted by factory built drag bikes running on alcohol fuels, were included in road "tests" which seemed to suggest the racers being tested were in fact street bikes of the type you could buy over the counter!

The reason for this type of deception was directly related to the introduction of the H1 Kawasaki, which could run faster times in totally standard unmodified form, than bikes with 250cc extra capacity.

The heavily modified Brit bikes used for "testing" got close to the H1 times, but not heard of any that were able to beat the consistent 12.4 runs of a properly ridden H1?

Any stock road going Brit was left for dead in relation to the performance of the H1, and the sales of the H1-H2 in the US seemed to suggest an awful lot of buyers were interested in levels of performance that had up to then only been available on a race track.

Carbonfibre said:

worntorn said:

I think some of the variation in 1/4 mile times comes from reaction time and the timing method used.
"How the timing lights might work if drag races are run using "rolling starts" is something you might like to explain?

Click to expand...

Click to expand...

The way it works at the Ramsey Sprint on the IOM is , a Sprint wrangler (my term) gets you lined up with front wheel on a line at the start. You go when you are ready and the timer starts as soon as your front wheel passes thru a beam which is a few inches ahead of the start line. This is a proper rolling start and offers a good comparison of the acceleration capabilities of different bikes.

I have read that US Magazine articles from back in the day using regular dragstrips (Xmastree type start lights)) would deduct an amount for reaction time and call the resulting time the "Adjusted" 1/4 mile time. They also made allowance for wind speed and elevation, so the number published could be a lot faster than the reality of a rider a couple of thousand feet above sea level with a bit of a head wind and a normal
reaction time.

The magazines then and now are all in the business of helping to sell motorcycles so the lower the number the better.

Glen

Matt Spencer said:

Theres Kawasaki forums elsewhere , old bean.

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How true, Matt, but I think we have an answer to the original question. The Mach IV never came anywhere near the 12.0 second elapsed time that was claimed for it.

For several years the stock Commandos outran the stock CB-750s but there was no surprise there. The CB-750 was 19% heavier with only 15% more power and had less torque. The stock Combats also consistently outran the Z-1s which were about 28% heavier with about 14% more power but I don’t remember the torque. It took a 1000cc before a stock four-stroke could consistently beat the Combat and I don’t even remember how many years it was before a four-stroke with 750 cc or less could manage it.

One thing I find surprising about the discussiions on this forum is how often “the Commando” is referred to as if there was only a single bike. There were at least five different engine configurations for the stock bikes and each one produced differing amounts of power and torque. If one version could only manage a 14 second quarter on a good day that does not mean a different stock machine with a more powerful engine could not be quicker. It is important to know which engine is fitted when talking about the performance of a stock bike.

http://www.kawtriple.com/mraxl/articles ... bikes1.htm

As mentioned, Cycle magazine did a back-to-back test with all the contenders back then.
12.28 secs for the Mach IV ain't hanging around. Especially for non-factory riders.

Note the 'gumball' tire mention tried on the Honda.
Better than alcohol,, and easier to fit - if it works !

12.69 on the Commando, was it.
No mention of alcohol either..

P.S. Perhaps the story has become twisted, and they go faster if the alcohol is in the rider ?!
Dangerous suggestion... !

Murray B said:

Matt Spencer said:

Theres Kawasaki forums elsewhere , old bean.

Click to expand...

How true, Matt, but I think we have an answer to the original question. The Mach IV never came anywhere near the 12.0 second elapsed time that was claimed for it.

For several years the stock Commandos outran the stock CB-750s but there was no surprise there. The CB-750 was 19% heavier with only 15% more power and had less torque. The stock Combats also consistently outran the Z-1s which were about 28% heavier with about 14% more power but I don’t remember the torque. It took a 1000cc before a stock four-stroke could consistently beat the Combat and I don’t even remember how many years it was before a four-stroke with 750 cc or less could manage it.

One thing I find surprising about the discussiions on this forum is how often “the Commando” is referred to as if there was only a single bike. There were at least five different engine configurations for the stock bikes and each one produced differing amounts of power and torque. If one version could only manage a 14 second quarter on a good day that does not mean a different stock machine with a more powerful engine could not be quicker. It is important to know which engine is fitted when talking about the performance of a stock bike.

Click to expand...

In the real world H1 Kawasaki would consistently and reliably run 12.4 ET 1/4 mile times, and while the Z1 was heavier and not quite as quick in the 1/4, away from the BS published in magazines no stock British made machine could best the Z1 over the 1/4.

That the performance of the Jap bikes was so much better than anything else around at the time, was validated by the sales of these bikes in the main market which was the US. Loss of so many Brit bike sales to Jap machines which were faster, more reliable and sold for less money pretty much sealed the fate of the Brit industry, which folded a few years after the introduction of the first true "superbikes"................

You must be thinking of the h2, the h1 wasnt that fast. I recall a kid at my school got a new h1 and claimed it would outrun anything. There was also a Norton 750 there, a yellow S model. After much bragging by the two bike owners and their friends, a time and date were chosen for the duel. The Commando won it handily.
I think the memory of that drag race and the sound of that yellow S powershifting thru the quarter with the wail of the Kawi (along with a fair bit of 2stroke smoke) is something ill always remember.
Never mind that Kawasaki came out with the 750 the next year. It was quicker than the Norton and all the others, but the die was already cast for me.

[

Rohan said:

...12.69 on the Commando, was it...

Click to expand...

From the article, “This year’s Commando... quickest ET, 12.896...”

It was the test in 1970 where the ‘69 Commando did 12.69.

None of this is surprising. The 1969 bike had 9.0:1 compression and the 1973 bike should have had 8.5:1 compression but they did not say. What it certainly did not have in 1973 was the high-performance 10.0:1 compression Combat engine because that had already been discontinued. Norton had announced a short-stroke 10.5:1 compression engine option at around that time but it appears to have been cancelled.

The Combats regularly outran the Z1s but I do not understand why you do not know this. Didn’t you go to the drag races back in those days? Kawasaki advertised 12.0 second ETs for the Mach IV but it never even got close to that even at sea level with a professional driver. The Kawasaki 1000 was the first stock machine that I remember doing a 12.0 ET.

Are you getting your information from books? There is an old saying, “A little learning is a dangerous thing,” and books rarely give more than a little.

Murray B said:

[

Rohan said:

...12.69 on the Commando, was it...

Click to expand...

From the article, “This year’s Commando... quickest ET, 12.896...”

It was the test in 1970 where the ‘69 Commando did 12.69.

None of this is surprising. The 1969 bike had 9.0:1 compression and the 1973 bike should have had 8.5:1 compression but they did not say. What it certainly did not have in 1973 was the high-performance 10.0:1 compression Combat engine because that had already been discontinued. Norton had announced a short-stroke 10.5:1 compression engine option at around that time but it appears to have been cancelled.

The Combats regularly outran the Z1s but I do not understand why you do not know this. Didn’t you go to the drag races back in those days? Kawasaki advertised 12.0 second ETs for the Mach IV but it never even got close to that even at sea level with a professional driver. The Kawasaki 1000 was the first stock machine that I remember doing a 12.0 ET.

Are you getting your information from books? There is an old saying, “A little learning is a dangerous thing,” and books rarely give more than a little.

Click to expand...

I wonder were you ever able to beat H1 and Z1 Kawasaki's on your own Norton, or are you simply relying on nonsense published in magazines which is about as accurate as claims about Iraqi WMDs?

worntorn said:

You must be thinking of the h2, the h1 wasnt that fast. I recall a kid at my school got a new h1 and claimed it would outrun anything. There was also a Norton 750 there, a yellow S model. After much bragging by the two bike owners and their friends, a time and date were chosen for the duel. The Commando won it handily.
I think the memory of that drag race and the sound of that yellow S powershifting thru the quarter with the wail of the Kawi (along with a fair bit of 2stroke smoke) is something ill always remember.
Never mind that Kawasaki came out with the 750 the next year. It was quicker than the Norton and all the others, but the die was already cast for me.

Click to expand...

An H1 ridden well will always beat a Norton, simply due to the fact its lighter, and has more power.

I wasn't even old enough to ride a motorcycle when Combat Commandos were new !
Bought an old dominator, and it was years before I even found what it was supposed to look like (someone had "Triumphified it). Even now folks who can tell you accurately about old Nortons you can count on the fingers of one hand....

I'd comment that the content in magazines seems to be a heck of a lot more reliable than some of the nonsense and memories and comments posted here and on the net generally. Wiki entries are just full of mistakes, writing stuff from memory obviously is not the path to true enlightenment. Cycle seems one of the more reliable mags, factually, subsequent stuff doesn't seem out of kilter with it at all. Anyone notice that CF suddenly became an expert when that Cycle magazine test link was posted - obviously he knows more than they do - obviously. (HOW ??)

My first memory of a H1 (?) was seeing one outside school, with a pillion on board. When he opened the throttle, it headed for the trees - but recovered it. If that thing could beat anything, I'd say "at what " - pointing a wheel at the sky maybe.

Riding a motorcycle competently is something that requires some degree of experience. Very fast and light machines such as the H1 or H2 need more rider input than most, hence the ridiculous nonsense about them not handling properly, and even claims that these bikes can be beaten in a drag race by old Brits with less power and more weight!

In terms of sports related machinery around in the 70s the Kawasaki 500 and 750 triples were pretty much the very best bikes available, being bulletproof reliable, and easily outperforming any other stock machines on sale during that period. They would certainly bite an inexperienced rider though, as they were in effect a race bike with road going equipment added.

For anyone who wasnt a reasonably good rider one of these bikes certainly wasnt that great an idea, as many riders simply couldnt deal with the levels of performance available, and often traded the bikes in following near misses, which in most cases were related directly to lack of riding ability.

:shock: Castrol 1Hour Production race .Levels raceway,Timaru, New Zealand. 1972 or 73 Dale Wylie on a Norton 750 beat Owen Galbraith Kawasaki H2.Could'nt match his speed on the back straight but easily passed him in the corners. :shock

Carbonfibre said:

Riding a motorcycle competently is something that requires some degree of experience. Very fast and light machines such as the H1 or H2 need more rider input than most, hence the ridiculous nonsense about them not handling properly, and even claims that these bikes can be beaten in a drag race by old Brits with less power and more weight!

In terms of sports related machinery around in the 70s the Kawasaki 500 and 750 triples were pretty much the very best bikes available, being bulletproof reliable, and easily outperforming any other stock machines on sale during that period. They would certainly bite an inexperienced rider though, as they were in effect a race bike with road going equipment added.

or anyone who wasnt a reasonably good rider one of these bikes certainly wasnt that great an idea, as many riders simply couldnt deal with the levels of performance available, and often traded the bikes in following near misses, which in most cases were related directly to lack of riding ability.

Click to expand...

,

They were like all of the other Jap bikes of the day, cheap and quite reliable for their relatively short lives.
I rode many of the Japanese bikes available back then. These bikes were affordable transportation and amusement for myself and my friends

I also had a good little business going doing mostly top end rebuilds of the popular bikes back then. Typically the Japanese bikes were in tough shape by the ten thousand mile mark. A rebore and valve grind(for the Hondas) would get them down the road another five thousand miles or so, then it was time to look for a replacment.
Of interest, the first bike I worked on with over thirty thousand miles on the clock was an old Es2.


One other thing about those early Japanese bikes, you would not want to ride long distances on them. The tingling vibration was awful.

I recently rode the Commando on a fast ride over the Duffey Lake road loop along with a friend on his 49 Vincent and his son on a new Triumph Triple.. This was a 500 plus mile day and I felt great afterward.

I wouldnt want to tackle such a ride on any of the Japanese machinery from that early era.

Interesting all those Jap bikes falling apart and wearing out in a way that seems strangely familiar! This being the case I wonder why the makers of far superior Brit bikes went out of business, and the Jap manufacturers are still with us today?

The Japanese bikes were cheap so they were affordable to the masses. The Japanese companies made a profit on each bike sold, the Brits did not.

It's easy to confuse the money situation with the quality of the product. To make money the product needs to be affordable and good enough, but not so good that it lasts too long.
Vincent is a great example. Philip Vincent was obsessed with building the fastest and longest wearing motorcycle in the world. He expected the bottom end to last at least 100,000 miles and then be rebuildable. This was unheard of in the 1930s and 40s , and was pretty rare in the 60s and 70s (maybe BMW?)
He accomplished his goal and the bikes are still doing big mileages to day , but he went broke doing so.

The Japanese import situation of the 1960s/70s was no different than the wave Chinese imports we see today. Back then, we had a saying - "its Japanese Junk" We used that saying a lot but still bought the stuff because it was affordable and better than having nothing.
I really wanted a Commando but got a Black Bomber instead. I used my imagination to turn it into Commando when riding.

Japan had cheap and devoted labour force, the UK had very expensive and militant labour force, thats mainly what killed them. Commando was bike of the year in the UK for about five years, but not everyone could afford one.

Once the Japanese had a foothold with their low pricing, they were smart enough to know that they needed to improve the quality of there products and did so. At the same time the Brits were making mistakes of there own as well (Combat) which did not help the situation.

I think by the time the MK3 was built Norton had a good overall machine (get rid of the stuffed up Black cap silencers tho), but it was too late, the Japanese had advanced quite a lot and the Brits had lost reputation plus the remaining almalgamation of Companies was mired in debt.

All very interesting...............the fact that the Brit industry were offering bikes with power unit designs dating back to the 1930's, which vibrated, leaked oil, and fell apart when ridden hard, were obviously all things that added to the mass appeal of these clearly superior machines over the cheaper Jap rubbish?

The design of the Commando engine itself dates back to 1948. Forgive me that I see nothing wrong with this. If you read up on the history of that design and the evolution of the Dominator models, you will see that a great many changes and improvements occurred. This continued thru the Commando years.

What I am saying to you is that I lived thru those years, was an avid motorcyclist and mechanic at the time. The Japanese bikes were not without their problems, but the low price and good reliability for a short life won out over high priced better handling and mostly longer life brit bikes. The fact that we are still riding these bikes on long runs should tell you that.

I havent seen a Kawi 2stroke on the road in decades, tho tons of them were made. I see Brit bikes from the 50s thru 70s all the time.

You wouldn't enjoy a 500 mile high speed run on a Kawi 2 stroke from the early 70s. Lots of smoke and vibration, huge fuel consumption and poor handling was the package. For the most part, none of this mattered. They were affordable and would wheelie, so for the kid zipping around town, what does the rest matter?

Rohan said:

I wasn't even old enough to ride a motorcycle when Combat Commandos were new! ...Even now folks who can tell you accurately about old Nortons you can count on the fingers of one hand..

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Yes, it is obvious that you are only repeating what you have read especially since you seem to have erased the Combat from history completely. Anybody that agrees with you is probably getting their stuff from the same books.

Rohan said:

...the content in magazines seems to be a heck of a lot more reliable than some of the nonsense and memories and comments posted here...

Click to expand...

This reminds me of a quote by Lord Northcliffe , “Journalism - a profession whose business it is to explain to others what it personally does not understand.”

The magazine article you mentioned does not compare the bikes to the quickest Commando with the Combat engine but to the much slower 1973 model. Norton, like every Detroit car I ever loved, decreased the compression and power across the board for the 1973 model year. The magazine article did not even mention the Combat even though the bikes were still making regular runs at drag strips all over.

Now, if you are implying that my engine data comes from memory that would be wrong. My data comes from a chart on page 54 of Roy Bacon’s “Norton Commando – All Models”. It lists six different engines that were fitted to the standard bikes. He has two separate listings for 850s one with electric start and one without. He also lists a short-stroke 750 that appears to have been produced and announced but never fitted to road bikes. [This one is a bit of a mystery sort of like the short stroke 303 cid. Firebird engine and Ram Air V option that was supposedly only available in racing cars.]

I think the Combat was a model that in hindsight Norton wished it had not produced, at least not the way in which it was done.

My cousins new Combat did just 1500 miles before the crank broke in half. This was not uncommon for that model.

Nortons answer was to increase the cubes,decrease compression, build a stronger crank with tougher main bearings plus beef up the cases on the mk3. I think this was a good response to the problem, but as stated, a bit too late.

Here is how Haynes describes the changes in their section on modifications to the Commando range-

"in March of 1973 the 750 range was supplemented by the introduction of an 850 model, the engine of which embodies several design modifications to enable the same power output as that of the 750cc Combat engine to be obtained, with less stress on the engine components"

Glen