certified quarter-mile time.

Recently I read a claim that a stock Mach IV was capable of running a 12.0 second quarter-mile. Back in the day this was also often said but I am unaware of any stock bike that ever did it. If memory serves the Mach IV was not even as fast as the Mach III but I could be wrong.

Does anybody know the track certified time for the fastest stock Mach IV compared to the fastest stock Mach III?

Someone recently posted some dyno charts that Cycle did back then - the Mach IV did 64.x hp, fractionally more than the Z1. They were said to be quick, being a lot lighter than the Z1. If the front wheel could be kept out of the sky....

Back in the day the H1 was pretty much the fastest bike around, and as its US price when introduced in 1969 was only $995 in comparison to around $1400 for slower 750cc bikes, it was very popular in the US.

Stock bikes would run 12.4 in the 1/4 mile, and there was no need for use of special race parts and running on alcohol fuels which produced 1/4 mile times which no production bike was ever likely to match, that were tactics often used by factories such as Triumph, BSA, Norton, HD.

The early stages of development of the H1 were slowed up by the fact that constant running at 118mph shredded the tyres available at the time, but this was resolved by working with Dunlop who designed a totally new tyre based very closely on current race tyre technology.

The HIB I owned was toned down a little from the drum brake A models, and while the handling wasnt great it was fine for anyone who was a relatively experienced rider, and certainly bore no resemblance to the nonsense that was written in the press about these bikes not handling.

Interestingly enough much of the initial development work on the H1 was carried out in the US, which subsequently proved to be the bikes biggest marketplace. At the time of its introduction 60bhp from 500cc, meant it had 10bhp over machines like the Manx Norton which was at the time still being used in serious racing.

Carbonfibre said:

Stock bikes would run 12.4 in the 1/4 mile, and there was no need for use of special race parts and running on alcohol fuels which produced 1/4 mile times which no production bike was ever likely to match, that were tactics often used by factories such as Triumph, BSA, Norton, HD.

.

Click to expand...

Alcohol fuel doesn't actually give any more power unless you can get the compression sky high.
And 1/4 mile running doesn't need a lot of heat removal, since it only runs hard for a short time and maybe a minute all up at a time, normal cooling is enough.

So where is your evidence for alcohol use ?
This sounds like hocus pocus harem scarem nonsense...

The evidence for alcohol fuel use in conjunction with special race engine parts, is plain to see in that the performance of test bikes which had been doctored in this way, was never ever equalled by any bike that was bought over the counter at a dealer!

Seems strange that buyers didnt seem overly concerned that the bikes they were buying simply didnt live up the BS performance figures provided by testing bikes with what were in effect race motors fitted!

A professional rider can consistently do times that an owner/rider may have trouble achieving, without considerable practice ? Dave Rawlins who did some quick quarters on the Norton Villiers 850 hotrod is quoted as saying he didn't get quick times until he got the hang of spinning the back wheel off the line, until the traction grabbed and off.

Nortons published Tuning Sheet 1 and Tuning Sheet 2, for the hot-rod 850 they had that blitzed the 1/4 mile times, and the flying 1/4 mile. Bumped the hp up considerably over a stock bike - nothing an owner couldn't have done themselves if they wanted to. Dennis Poore is quoted as saying he wanted the bikes built to that spec. But they wouldn't meet noise regs.

Given what happened with the Combats, this may have been a wise move to keep the factory 850 builds fairly low key. Some owners have reached quite big mileages with stock bikes.
Must have dodged all the deliberate union sabotages ??

Thanks for the launch detail Rohan as something i want to work up to and not flip over my dairyaire. The Combat down fall wasn't it power set up but bad machining of ignition advance and a bunch of other stuff that we can work around now. Full power take off is second only to full power braking skill for scary dangerous to me. Too much hook up to take off or not enough hook up braking is can do mean things. Any of ya practice this? Of course its adds severe wear and tear to the drive train. If not launching with power enough to spin tire and lift front, subtract about a second off 1/4 m ET's which implies a good Cdo is a mid 13 sec machine in public.

Of course away from the net forums not many riders can get anywhere near the 1/4 mile times that would come easily to an experienced racer.

In the case of the doctored test test bikes though, even an experienced racer would probably find it very difficult to get anywhere near the times set by rider just as good, on a modified machine with perhaps 20bhp more than a stocker.


The Japanese sometimes modified test machines, but not heard of any which used alcohol fuels to allow them to run ultra high compression to help specifically with good 1/4 mile times?

hobot said:

...The Combat down fall wasn't it power set up but bad machining of ignition advance and a bunch of other stuff that we can work around now.

Click to expand...

Don’t forget Washington’s meddling, hobot.

In Jim Campisano’s “American Muscle Cars" there is a chapter that begins, “1968-1974...Tin Soldiers and Nixon’s Coming”. The chapter describes an end of North American high-performance vehicles. He writes, “This Is the End...The downward spiral began in 1971 when General Motors took the first big step by lowering compression ratios and detuning all its supercars in preparation for the imminent arrival of unleaded fuel. Immediately power dropped noticeably and new emission control devices siphoned away even more grunt...By 1973 performance was a four letter word around Detroit.”

For the 1973 model year Norton also lowered compression to 8.5:1, dropped the Combat, and cancelled the short-stroke high-compression (10.5:1), 750 Roadster. Even with the increase in displacement to 828 cc the new stock Commando ran the quarter in the low thirteens instead of low twelves as the stock 750 Combat had done. The “850” was still a “superbike” but not quite as super as before.

Banning lead forced oil companies to reduce the octane rating of the fuel and NOx emission restrictions kept it that way for years. How long was it before any Detroit Iron could again be ordered from the factory with a 400+ h.p. engine?

Carbonfibre said:

The Japanese sometimes modified test machines, but not heard of any which used alcohol fuels to allow them to run ultra high compression to help specifically with good 1/4 mile times?

Click to expand...

Personally, I think this is a load of old cobblers, Grandma.

Chucking a hot cam in something I could perhaps maybe possibly almost believe.
If you had the evidence...

Carbonfibre said:

Of course away from the net forums not many riders can get anywhere near the 1/4 mile times that would come easily to an experienced racer.

Click to expand...

Good at backpeddling when you have previously posted a load of total nonsense, and someone points it out, aren't we ?

Rohan said:

Carbonfibre said:

Of course away from the net forums not many riders can get anywhere near the 1/4 mile times that would come easily to an experienced racer.

Click to expand...

Good at backpeddling when you have previously posted a load of total nonsense, and someone points it out, aren't we ?

Click to expand...

I wonder do you know who Mike Jackson is? And as you dont seem to believe the reasons why test bikes were in some cases an awful lot quicker, than bought over the counter road machines, then perhaps you could indicate any evidence to support a stocker getting anywhere near the fictional magazine "performance" figures?

Don’t forget Washington’s meddling, hobot.

Click to expand...

Ugh Murry, I lived through that era - gas lines around the block and Nixon's price fixing. But was also the Era of my P!! dragster so was king of the sprinting games in Florida in its hey days. Ran great on Hi Test Ehtyl.

If the stance of a Norton Twin is lowered enough wheelies don't happen only tire smoke or LEAP forward to float level but still helps to learn to shift WOT with just a kill button tap, a Big Button of course.

Carbonfibre said:

I wonder do you know who Mike Jackson is? And as you dont seem to believe the reasons why test bikes were in some cases an awful lot quicker, than bought over the counter road machines, then perhaps you could indicate any evidence to support a stocker getting anywhere near the fictional magazine "performance" figures?

Click to expand...

Magazines would use a pro drag racer who weighted about 125lb and on a well set up "S" they did a one time best of 12.69. I at the time probabbly weighted 50 pounds more and managed a 13.995 on my "S" after only 3 runs. Broke the gearbox on the last run so I could not try to see if I could do better. I am sure my "S" was fast, especially considering the slug on the seat, the lack of any preparation and no ¼ mile experience.

Jean

Carbonfibre said:

I wonder do you know who Mike Jackson is?

Click to expand...

Did he meet Elvis ?

Do you know who Louden Wainright is ? (name plucked at random out of the ether).

Carbonfibre said:

And as you dont seem to believe the reasons why test bikes were in some cases an awful lot quicker, than bought over the counter road machines, then perhaps you could indicate any evidence to support a stocker getting anywhere near the fictional magazine "performance" figures?

Click to expand...

The Norton Villiers 850 factory hack that blitzed the 1/4 mile was a well worked FACTORY bike - it was fast, and the factory said it was fast because of that. And told you how they did it - the heart was that 4S cam. They published its best 1/4 mile time in the 850 brochure.

If the other bikes were so unbelievably fast, how come the factory Norton 850 was generally faster. Doesn't say much for their alcohol ?? breathing monsters, does it ?

Lets not forget the brochure quoted 1/4 mile time may have been the best time that a dozen test riders achieved in a month of Sundays, its not like they waltzed out, did one run of the fastest time ever, and all went home....

P.S. 2 strokes don't like alcohol and high compression, so we can probably rule that out for the H1 and Mach IV to begin with ? Expansion chambers on strokers are a fairly sure sign its not stock either....

hobot said:

...I lived through that era - gas lines around the block...

Click to expand...

Yes many of us did and do you remember the year and season the lines started? Do you believe the gasoline shortages marked the beginning of the "Energy Crisis"?

Rohan said:

Carbonfibre said:

I wonder do you know who Mike Jackson is?

Click to expand...

Did he meet Elvis ?

Do you know who Louden Wainright is ? (name plucked at random out of the ether).

Carbonfibre said:

And as you dont seem to believe the reasons why test bikes were in some cases an awful lot quicker, than bought over the counter road machines, then perhaps you could indicate any evidence to support a stocker getting anywhere near the fictional magazine "performance" figures?

Click to expand...

The Norton Villiers 850 factory hack that blitzed the 1/4 mile was a well worked FACTORY bike - it was fast, and the factory said it was fast because of that. And told you how they did it - the heart was that 4S cam. They published its best 1/4 mile time in the 850 brochure.

If the other bikes were so unbelievably fast, how come the factory Norton 850 was generally faster. Doesn't say much for their alcohol ?? breathing monsters, does it ?

Lets not forget the brochure quoted 1/4 mile time may have been the best time that a dozen test riders achieved in a month of Sundays, its not like they waltzed out, did one run of the fastest time ever, and all went home....

P.S. 2 strokes don't like alcohol and high compression, so we can probably rule that out for the H1 and Mach IV to begin with ? Expansion chambers on strokers are a fairly sure sign its not stock either....

Click to expand...

Mike Jackson was I think US sales manager for Norton at around about the time the Commando was introduced, and knows all about the "alterations" that were done to produce Norton 1/4 mile times approaching those of stock H1 Kawasaki's.

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.

Denco Kawasaki H2's being raced in the late 70s early 80s ran on alcohol fuel, and with a displacement of 800cc had just about the highest power to weight ratio of any atmo bike around at that time.

And the Mitsubishi Zero was a better plane than a Spitfire .

Untill it got a cannon shell or 50 calibre slug in it . . . .,

Theres Kawasaki forums elsewhere , old bean . :lol:

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 ?

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