Your guide to Kawasaki H1 Mach III

It stood out then and still stands out today. The H1 makes a great classic, but does it live up to its ‘Widowmaker’ nickname?

Words by OIi ‘I want one’ Hulme, with photography by Gary ‘oh, another old bike’ Chapman

The pace of motorcycle development in the 1960s was astonishing. These days, a major manufacturer might spend two years on a new paint scheme and announce it with a full media launch and mass of information, while a revised set of switchgear is treated like a space rocket launch. In the mid-1960s, they did things slightly differently.

Kawasaki had tried and failed to build motorcycles in the mid-1950s with the Meihatsu brand, and then in 1960 entered into a partnership with Meguro. Kawasaki was very much the senior partner in this enterprise. It was not called Kawasaki Heavy Industries for nothing, making ships and turbines, railway locomotives, and, most famously, aircraft. Indeed, the company’s first motorcycles were badged as Kawasaki Aircraft, which was a ballsy decision for a company with designs on US sales, given that the previous US contact with Kawasaki was Second World War fighter aircraft shooting at B29 bombers.

With Kawasaki’s industrial muscle backing up the company with a substantial manufacturing skill base and lots of money, motorcycles became a flagship. Meguro had been building the Meguro K, a licensed-built version of the BSA A7 (details of the actual licensing deal are scant), which was a high-quality machine but had lubrication problems. Kawasaki absorbed Meguro completely in 1963. Kawasaki rebranded and redesigned it to sell as both a Meguro and as the Kawasaki K2, enlarged it to become the Meguro X-650, and then sold it as the Kawasaki W1.

Although it was the biggest motorcycle then made in Japan, in the days when a 650 was a superbike, the W1 was dated – and Kawasaki had bigger ambitions.

Japan was at the start of the ‘Izanagi boom,’ when Japan’s economy grew enormously in a few years and caught up in this race for growth, Kawasaki was inspired to develop a new product. This was called variously Project Blue Streak or Project N100.

Honda had recently introduced the four-stroke CB450 ‘Black Bomber’ and Suzuki had made the two-stroke T500, both as fast and, importantly, more sophisticated than many British 650s. Kawasaki wanted some of this action.

Although they had successful 250 and 350 twins, they realised that US buyers wanted bigger bikes, and that those buyers were frustrated at Harley-Davidson’s ponderous models and the questionable build quality of some dated British designs. 

Kawasaki’s response envisaged new high-performance motorcycle concept. Capacity wasn’t the issue, but speed and power were. The specification for the N100 plan was to build a motorcycle with an engine that would produce 60bhp and provide a standing quarter time of 13 seconds.

The N100 plan was launched in February 1967 and work on the engine began in July. The engineers looked at two teams looking at engine concepts. These would either increase the bore of the existing disc-valve 350cc Avenger twin to make it into a 500 or build a completely new engine. For this new engine, they looked at building a two-stroke triple. At first, this was built in L-format, with a single-cylinder projecting from the front of the crankcase to help keep all three cylinders cool. Working with Osaka University’s faculty of engineering, it was determined that a simpler inline configuration would not impair cooling. This simpler arrangement was the format chosen, as straight-forward piston porting on a triple was much cheaper than putting disc valves on a twin. The way a triple produced its power compared to a twin put less stress on the clutch and gearbox, which meant that in turn these components could be lighter and cheaper. Opting for piston porting meant that new motor was only an inch-and-a-half wider than a disc valve Avenger twin.

There were three carburettors, operated by individual cables running to a splitter that was controlled by a single throttle cable. A second cable on the twist crip controlled the ‘Injectolube’ two-stroke oiling system.

A frame and cycle parts using many of Kawasaki’s existing componentry was put together, a striking new look was created, and in September 1968 it announced that the new motorcycle, dubbed the H1 Mach III, would be coming very soon, having not just created an entirely new engine, but a whole new motorcycle from scratch in just over 12 months. Kawasaki test rider and feted drag racer Tony Nicosia rode the prototype on back roads around California, Utah, and Nevada in the cold winter of 1968. He claimed that the H1 was so stable he could ride it at night with his hands in his pockets. He put 650 miles on the prototype using two engines, and this ‘seat of the pants’ testing regime showed that two engines performed very differently – one very quiet, and the second “sounded like it was going to fly apart.”

At a launch in the USA in February 1969, Kawasaki claimed the new triple had 60bhp, a top speed of 124mph, and would do 12.4 second standing quarters, making it one of the fastest production motorcycles ever made. This was treated with some cynicism by motorcycle journalists until independent road testers managed 119mph top speeds and 13.2 second quarters on test bikes.

Tony Nicosia took a production H1 Mach III across the USA on a tour of drag strips and he proved Kawasaki’s claims had weight; the H1 really was that fast. Although Honda had stolen its thunder with the new CB750/4, the H1 was found to be the fastest mass production motorcycle available at the time in the USA. It was also cheap. The H1 cost $995 in the USA. By contrast, Triumph’s T150 Trident, launched at the same time, was slower, and cost $1795.

The H1 was a perfect motorcycle for a country with long, straight roads and fast, wide boulevards.

The H1 was a truly modern motorcycling creation, launched with CDI ignition, oil injection and intimidating handling, with breathtaking acceleration and top speed. Power was taken from a roller-bearing crank to the transmission through a gear primary drive and sent to the back wheel by a five-speed constant mesh gearbox, one more gear than most riders were used to.

There was no electric start, but it was easy to kick over. It wasn’t faultless, however. The CDI system was developed from a system based on one used with some Kawasaki race bikes and it was not without its problems – it used a distributor that had a weak bearing that could fail. And while it was hugely fast in a straight line, if were there were no long, straight highways or dragstrip-style boulevards, things turned out a little differently.

The H1 – and some say all Japanese motorcycle culture at that time – was about the engine. But it had arrived with that fire-breathing engine wrapped in a frame of dubious design. Suffering from a poorly configured swingarm pivot made with indifferent manufacturing tolerances, the 500 Kawasaki had skinny front forks and frame tubes, an overly powerful and insensitive drum brake, and a set of shock absorbers from the 250 Samurai. Handling was clearly not top of the Kawasaki agenda. If you look at the frame of an early Kawasaki triple with modern eyes, you can see the root of the problems. The steering head is heavily braced, but it is not triangulated. The top strut heads backwards at a short, sharp angle, putting all the stress from the steering head in the middle of the top tubes right above the engine, instead of further back. That engine, meanwhile, was set rather further back in the frame partly to improve cooling to the middle cylinder, and this was less helpful for stable handling and badly affected the steering geometry on bends, while all the power came on at 6000rpm, making any journey and exhilarating, nay terrifying, experience.

The frame would inevitably flex. Visitors to the factory where Kawasaki made the frames reported that they were made by welding two sides of the frame together, rather than constructed as a single unit.

Kawasaki had built a motorcycle in which power was everything and there was no consideration for handling and therefore safety, while respect for the environment from the 24mpg machine and respectability was not part of the equation. Yet racing versions won Grand Prix in the startling livery that became Kawasaki Green.

The different responses to the H1 in the USA and the UK were marked. American journalists given the machine in a balmy Californian spring of 1969 raved about the power, declared the tyres to be wonderful, the handling positive and the whole package a work of genius. Over in dear old Blighty later that year, where the streets were potholed (no change there), where there were still cobbled streets in the inner cities, and where the roads were wet and oil-slicked and had actual bends, the praise for the handling was more muted. For once, the high and wide handlebars were deemed essential for effective steering, rather than a transatlantic fad.

The big drum brake was either on or off and faded rapidly in hard use going into UK bends, giving a new terror/excitement to scratching, with many machines ending up on grass verges or worse, while the Japanese Dunlop K70 tyres fitted as standard were notoriously bad on any bike. And, like the brakes, the carburation meant the engine likewise had two settings: on or off.

The triple might have been exciting, but it didn’t take long for sales to be hit by the H1’s unpredictability on the road, and Kawasaki was faced by a triple whammy of too much power, threats of legal action for product liability, and rapidly increasing emissions regulations. The power was dialled back in stages over the years from the alleged 60bhp to about 52bhp, which was still remarkable for a 500. Over the years there were improvements to frame design, too. A new front disc helped create a slightly more manageable reputation but did not dilute the legend too much. Yet this reputation for being a hair-raising sportster did affect sales and the H1 was rejected by many buyers for the ‘exhilarating’ handling, thirst, and peaky power delivery, while Kawasaki took the wind out of its own sales by launching the even more extreme H2 750 triple.

However, in the early years, the H1 simply obliterated the competition, making the bike a legend. Rivals such as the Honda 450cc 45bhp Black Bomber or Triumph’s 500 Daytona with 40bhp were simply blown into the weeds. They were left as a distant speck in your rear-view mirrors.

The models
Kawasaki offered new versions of the H1 every year, with technological upgrades, new paint schemes, and cosmetic changes.

1969 H1 Mach III: The fixed capacitor discharge ignition was ground-breaking, if primitive, and there was the twin leading shoe front drum brake. The gearbox was five-up, with neutral at the bottom, and you could swap round the gearshift from right to left should you desire it if you were used to British or Italian shift patterns. The tank featured deep knee scallops and there were Mach III badges. Few 1969 models came to the UK as Kawasaki did not have an official importer at the time, but plenty have since, as grey imports.

1970 H1-500: Changes for 1970 were mostly cosmetic, with changes to the paint scheme and trim. More of these bikes arrived in the UK with the appointment of an official importer Agrati. The principal difference between UK and US bikes was the use of points, rather than the new-fangled CDI set-up. This was down to GPO, which regulated radio and TV broadcasts and found that that the CDI ignition would interfere with TV and radio signals.

1971 H1A-500: The tank lost its scallops, which was not just a shame, as they were very attractive, but a pain for those who like to restore to standard. Finding the earlier tank isn’t quite on the level of hunting for the holy grail, but close to it.

1972 H1B/C-500: A new paint scheme became the Kawasaki standard look for a few years. There were further trim changes, painted mudguards, more colour-matching and polished engine casings and there were changes to the instruments and other equipment. Most significant was the use of a disc brake at the front. This was better than the drum and a hydraulic steering damper was added on top of the existing friction damper. The silencers and airbox were modified to make things slightly less antisocial, which cut power. But everybody fitted expansion chambers, anyway. The H1-C was a rare parts bin special model with a front drum brake and a white paint job. The H1B is probably the most attractive model today, as it had many of the earlier bugs ironed out but still retained the authentic triple feel.

1973 H1-D: 1973 triples got some much need modifications to handling and further reductions in power. More colour options saw the adoption of Kawasaki Green, there were more mods to the silencers, which became a connected unit instead of three separate pipes, there were frame changes, moving the engine slightly forwards, and the central friction damper was removed and a heftier hydraulic unit offered. There were better shocks and the CDI unit was reintroduced in the UK having been changed to the unit used on the H2 750.

1974 H1E: Changes were limited to a further revision of the CDI system, some engine breathing mods and slight alterations to the trim as efforts were made to make the H1 more respectable. It also got anti vibration rubber engine mounts. The H1E is probably the easiest H1 model to live with.

1975 H1F: Largely unchanged from the E model apart from minor changes to trim, austerity was starting to bite as side panel badges were changed to stickers. The H1 moniker was subsequently dropped and replaced with the slower, less powerful, and thus less charismatic 52bhp KH500 which had H1F engine and frame numbers. The KH lasted until 1977 when Kawasaki headed for DOHC in-line four territory with the Z650 four taking over the middleweight sportsbike role.

Despite, or perhaps because of, gaining a macho reputation for unpredictable, hairy-chested behaviour combined with the all-conquering straight-line performance, the Kawasaki triple concept survived as a 250 and 400 in the line-up until the early 1980s, by which time it was an anachronistic and glorious throwback to the days of flares and patchouli.

Riding an H1

The H1 comes with that fearsome reputation, but what is it like to ride?

Classic Motorcycles Ltd of Cheshire had a late-model H1 in stock from 1976 for a reasonable £8999 and kindly let me have a ride on the allegedly unrideable monster. Now, by ’76, the H1 was toned down a little and substantial changes had been made to the frame and braking. It looked fab in Kawasaki Green and it had a stance to die for.

Okay, so time to get to grips with this terrifying behemoth. It started first kick, as one might expect from a well-presented two-stroke. Remembering the all-up gearchange, I gently pootled off down a lane, waiting to be eaten alive.

I got to a junction and took it down to first, by now having completely forgotten that neutral was at the bottom, and I slipped the clutch to accelerate and got nothing but a big noise from the silencers and a momentary wobble. Oh, yes. Up into first. It wasn’t the first time this happened, as muscle memory always expected a gearbox to go into first at the bottom. It is odd, as I can always switch happily from left to right shift, and even down for up, but this aspect the Kawasaki remained confusing all throughout our brief relationship. The last thing you want to do in slow traffic is suddenly find yourself with no go.

Then I forgot to turn the fuel on and reached down for the fuel tap… only it wasn’t there. It wasn’t on the right either. I had to get off and rummage around under the tank until I found it, mounted in the middle, and I’m not sure what the designers were thinking when they did that.

Still, fuel on, boot it over, and we are ready to roll again. Up into first, rev gently to 2500rpm, give it a bit more throttle, and suddenly things started to happen very fast; hello, baby, what is going on here? It was utterly invigorating, though thankfully not uncontrollably so. The much-vaunted terrible handling turned out to be a myth, at least on this later model, the H1 went smoothly through corners, and I could chuck it about with something close to aplomb. There was no footpeg scraping or anything close to that – I’m not into that sort of nonsense. It was just a joyful, full-of-beans romp. There was no wobble, no ridiculousness, and the acceleration, while dramatic, was far from being uncontrollable. I can imagine that giving it big handfuls might have made things more exhilarating. Otherwise, my criticisms are limited to the switchgear being a bit rubbish and the seat a little firm for my aging posterior.

I was left wishing that these bikes were not quite so legendary, and thus expensive, so more people could enjoy them.

How much does a H1 cost today?

If you are looking for a H1 today, you will need deep pockets. Most are imports, and a restoration project that is mostly complete but will need a ground up rebuild to work properly will start at about £4000-£5000. Remember, a project is likely to require an enormous amount of work, and specialist mechanics and restorers are thin on the ground. You can find a runner with a few scuffs and scrapes for £7000-£9000, while polished show quality bikes cost between £9000 and £12,000.

While early bikes used to command the highest prices, these days even a late 1976 model in top-notch condition with set you back £11,000.
Kawasaki Triple fans have their personal favourites, and the bikes from the first three or four years are the most striking in appearance, but it should be remembered that bits for the early models are going to be hardest to find, while Kawasaki setting up its own UK import department in 1974 improved supply of both parts and bikes. The later models had better equipment too.

Specification
Engine: Air-cooled three-cylinder two-stroke Capacity: 498cc Bore/stroke: 60 x 58.5mm Power (claimed): 60bhp @ 7500rpm Carburation: 3 x 28mm Mikuni slides Transmission: Five-speed, wet clutch, chain final drive Frame: Tubular cradle Suspension: Telescopic forks/twin shock Brakes: 2LS front/SLS rear Tyres/wheels: 3.25×19, 4.00×18 Weight: 171kg Top speed (claimed): 125mph

Parts

Simon Lister
www.kawasakitripleparts.com/

Z Power

www.z-power.co.uk/

Cradley Kawasaki

www.kawasakioriginalparts.com

BOXOUT

Information

Dale’s website contains huge amount of advice and information about buying, restoring, and running all Kawasaki triples and is an essential source of information: https://kawatriple.com/

Owners’ Club
The Kawasaki Triples club is an extremely enthusiastic and friendly organisation with 15 branches in the UK and organises several events each year: kawasakitriplesclub.com