40 Years On. The Kawasaki 750 H2

Post date: Oct 13, 2012 10:5:26 AM

The Kawasaki 750H2 has developed a 'mythical' reputation over the last forty years. With in our club we have a number of H2s that are used on a fairly regular basis. A couple of weekends ago Kim and Alan took their H2s out for a spin to Pongaroa and they really confirmed they are a great 'every weekend' classic. But what is it really like to own, ride and fettle an H2 forty years on? Alan Clark, Barry Drummond and Paul De Lautour have put pen to paper and shared there experiences.

Gary

KAWASAKI H2 – 40 YEAR ANNIVERSARY

For many, Kawasaki triples along with Suzuki GTs and Yamaha RDs provide a snapshot of the 1970's. A time when motorcycle manufacturers endeavored to produce something different from their competitors, and you could tell at a glance a make and model. Even the sound was distinctive. A time when anything went and anything that went fast was probably a 2-stroke.

If Honda had rattled the establishment in 1968 with the launch of their 750 Four, Kawasaki rocked the motorcycle world with the H1 500 triple (Mach3) in 1969. The 60 bhp 120 mph 2-stroke rocketship was the fastest production motorcycle with the best power-to-weight ever. Then in 1972 Kawasaki released the H2 (Mach4) 750 2-stroke triple. With 74 bhp and 57 Ft-Lb of torque on tap, the the 192kg H2 took performance to a new level. It was outrageous, it was exciting, and it was affordable. It became a legend in its own time.

So much has been written about the H2 and such is the myth surrounding it, that its hard to know what is true and what is not. To that end here is my personal experience of H2 ownership, and that of friends who also ride H2's.

I purchased my 1972 H2 May 2010. The bike is an unrestored example in Candy Gold, and had 7500 miles on the clock at the time. Lest the purists howl, let it be pointed out that at least 150 Gold H2s were exported from the factory during '72. This bike is number 249 from the end of H2 production, and has the H2A spec engine. The only deviation from standard are the chrome clock surrounds which were added at some point in it's past, presumably to add some bling!

http://kawtriple.com/mraxl/articles/1973 Superbikes/superbikes1.htm – link to Cycle Magazine's 1973 superbike test

----------------------------------------Alan Clark----------------------------------------

Owning an H2 Kawasaki

I have written this at the possibility of being lynched by my motor cycle colleagues. I own a 1976 Kawasaki 750 H2C which is an ex USA bike. She had 8,500 miles on her when I got her. It has now turned 11,000 miles. It is standard as she came from the factory, except the tires.

This model had the longer swing arm and engine moved forward a bit in the frame, to stop the wheelies. It has better handling. (Supposedly)

Reality is, the H2 is an awful bike. It is very anti green. (despite that being the race colour of that era.) At not too much above the 100km/hr speed limit, it vibrates badly. I have spoken with many people about this. Most seem to think this is fairly normal. I don’t know how the old racers like Peter Flemming, Alan Collison and the likes, used to hang on to them at speed & high revs. They just vibrate so much. Motorcyclist have truly been spoilt since the 4 cylinder bikes came along and engine balancers & the like.

But still an H2 is an H2. That is all that really matters. The reputation really precedes the bike. I believe the reputation of the bike far outweighs the reality of its overall riding experience & even its existence. I don’t know how wrong Kawasaki got it compared to the Suzuki GT750. (I think a far better bike.) If Suzuki had bought out a sports version of the GT750. I am sure it would have killed off all H2’s for ever. Suzuki sicked around with that awful rotary instead.

Sorry guys but that’s how I see it. In another 20 years, will anyone even care about H2’s, except those bought up in the motorcycle fraternity.

Now having got all that off my chest.

The other side of owning an H2 is everybody who has ever had an interest in Japanese motorcycles, knows of the Kawasaki triple reputation for speed, thirst and damn good styling. The bikes are quite a looker. The tailpiece; that tail piece alone has to be the biggest influence on motorcycle styling, for manufacturers in motorcycling history. The lack of a rear mudguard. Those three pipes. How neat the unbalanced look really is. The sound of the a triple engine with straight cut primary gears. The howl of the carbs sucking in the air and fuel. Yeah, it is pretty neat to be on one of these H2’s.

If you take an H2 down town, the amount of people who come and have a close look, or even ask to sit on the bike is amazing. Even your girlfriend (Wife nowadays) will take second place as the blokes perv at the bike and not the girl. They all want to see wheelies. Well that is a bit of a myth for my model. The power stands ain’t that great in reality. Wheelies were an effort for a stock bike. Today it is too much effort. (I may put my back out). Then you have to stop, and that side of an H2 is pretty poor as well.

What I enjoy most about riding the H2 is the amount of torque. They are grunty. You don’t have to rev them hard to go fast. You can go quick, by short shifting. They are so torquey. Just ask an NS400 rider over the Parapara’s. If you do rev the H2, beware of your hands going numb or slipping off the handlebars.

Then there is the Arabs who absolutely loved H2’s. We religiously filled the petrol tank every major town. Yes, if you can afford to make them go fast, it will cost you more than an old car. I think H2’s alone set up Dubai. The overseas currency we gave them. And if you do go fast, the smoke may kill off any would be followers, but they will catch you up at the next petrol station anyway.

50 mpg from an H2. I was skeptical when I heard of this, I had always considered 27 mpg to be good for my H2.

Recently I was touring at the legal speed with these other H2’s. The fuel consumption on mine was about the mid 40’s mpg. I was stunned. A few even did get just over 50+ mpg. So H2’s can be toured and be cheap to run.

As always this is only my own interpretation of owning an H2. I’m sure many will disagree with me. Yes I have re-shimmed the engine and it helped. Throwing away the original weighted handle bars also helped. I got another 30 km/hr before my hands go numb from the vibrations. What other bike has the reputation. Cool styling, noise, smell, beautiful lines. Am I a proud owner of my H2? Hell yes. The bike doesn’t even have to do anything. It will always be an H2. A real piece of Motorcycling history.

-----------------------------------Barry Drummond------------------------------------

Jetting Your H2

We have all heard the plaintiff cry - “my H2 bucks like a rodeo bronco, especially on the over-run” The reason is relatively simple – it's too lean; probably on the needle. Before we start looking at solutions, lets first have a look at what we are dealing with here:

Early H2 had H2-1 carbs with 105 main jets.

Later H2 and H2A had H2-2 carbs with 97.5 main jets, different needles & needle jets. Some H2As had H2-4 carbs, but set up as per H2-2 example. The net effect of this change was to give a leaner but more economical set-up along with a theoretical 3 bhp drop in power.

All H2B and H2Cs had H2-5 carbs with 102.5 main jets and needles & needle jets as per H2-2 but with the needle position 1 groove richer.

The reason for this inherently richer set-up was that as part of the lubrication system on these models oil was pumped to the carburetor bowls, which meant that the jetting had to be greater in order to pass oil as well as petrol without being too lean.

Corresponding to these changes in carburation Kawasaki introduced three different cylinder barrels each with distinctively different porting. As well as these differences the original pistons in the H2 and H2A models were quite different to those introduced for the H2B and subsequent H2C models. These later pistons superseded the originals as a Kawasaki Genuine Part and had the effect of drastically altering the transfer port timing. These engines were a further 3 bhp down on power.

Rush the clock forward 40 years and how many H2s are there with their original carburetors, cylinders, and pistons? This writer knows of only one. Consequently, most remaining bikes will contain an unqualified “mix & match” of all the various components made by Kawasaki, not to mention after-market pistons etc. Another variable to take into consideration is piston to bore clearance. Assuming that all crankshaft seals are in good condition a tight top-end will be inherently richer than a worn one.

Solutions – Due to the extreme number of variables there is no magic formula. However, all carb slides are the same having a 2.5 cutaway and all pilot jets need to be 35's with the exception of H2B & H2C which are 40's.

Experimentation is required with main jets ranging from 95 to 102.5 typically, and the altering of needle position. A richer position will give smoother running at the expense of economy. H2's do not need to be thirsty. If you get it right, figures on the high side of 60mpg are achievable running on the highway at legal speeds using a steady throttle. Just keep reading those spark plugs.

-------------------------------Paul DeLatour--------------------------------------------