No fuel injection here, just old-school flat-slide carbs feeding fuel to the cylinders.
Back in time, before nonsense like catalytic converters, fat-free fries and the belief that fumes from carbon-based automotive fuels cause the skies to darken and your genitalia to shrink, the easiest way to go faster was to make the engine larger. Team Green became famous for pushing the envelope of power.
The 1972 Mach lV was released on the heels of an earlier Mach III. The difference between the two bikes was that the Mach IV rocked a larger motor. Kawasaki adverts of the day lauded the H2 750cc triple’s 12-second straightline performance, 126 MPH top speed and its new “race-designed” front disc brake. In the early 1970s, the H2 came with approximately 70 HP. Reworked carbs and a set of ear-splitting expansion chambers would get you another 20 HP or so, mild porting produced 10-15 additional ponies and wild porting garnered over 120 total HP. Expert tuners like Paul “Fast by Gast” Gast were soon squeezing more than 150 HP out of the H2.
Like Gast, Alan Bernard has equal respect for the Big K’s two-strokes having raced them before opening a custom bike shop called Santiago Chopper Specialties (SCS). A couple of years ago, Bernard bought a complete collector’s hoard of vintage Kawasakis that was collecting dust in a Midwest barn. While many of the bikes were far from complete if not dilapidated, there was also a handy cache of spare parts that included a Gast-tuned 750 H2 race engine.
With a garage of parts and a strong three-cylinder engine, Bernard with the help of shop mechanic Mike Lima, pulled the race motor out of the heap and had the engine rebuilt with new seals and gaskets followed by polish and paint. He also replaced the special Gast race-cylinder heads with a pair of original H2 heads as the small finless Gast heads overheated very quickly when the bike was ridden on the street—the downside being a drop in 10 HP on the dyno to a claimed 140 HP.
Bernard used skills acquired from an earlier build that worked an H2 motor into a 1985 GSX-R750 frame to fit his Gast motor into a modified 1988 J-model Gixxer 750 chassis. It did not fit in easily though. Every time he bolted something else on the bike (after fitting the motor into the frame), it caused a major rethink. The last hiccup being a kickstart lever that made contact with the expansion chamber—hence the zigzag shape of the kicker lever.
After making a new rear subframe, Bernard had expert alloy welder Rob Hitch fry it in place and slipped a modified Gixxer fuel tank on the frame in front of the fiberglass replica Ducati Imola seat unit. The Italian route was also taken for the front fork, wheel and brakes, kindly donated by a Ducati 1098 Bernard had lying around. GSX-R1100 clip-ons, custom billet grips and Pazzo race levers added improved ergos and style. And the rear end also came from a Ducati. An entire 1100 single-sided setup complete with Ducati/Öhlins shock and custom stainless steel chainguard by SCS transformed what was a classic Kawi into a grab bag of sportbike parts from around the world.
Bernard had painter Craig Skiver green-up the entire bike in the right shades of Godier-Genoud racing colors. Bernard affirms the engine is as fast as Gast originally made it back in the 1970s. And he says that while the powerband has all of the attributes of a light switch, the Gixxer frame and Ducati suspension have transformed the H2’s handling from cornering like a drunk on a skateboard to having a degree of actually going in the direction where the front wheel is pointed. Bernard also reports that the instant on-off characteristics of the Gast drag-race tuning scares him shitless when the throttle is twisted in anger. But riding the bike would only be half as much fun if it didn’t.
Kawasaki H2 Hybrid
Front End: Ducati 1098 fork legs and yokes, wheel, brake calipers, rotors and master cylinder, GSX-R1100 clip-ons, clutch lever and throttle assembly, stainless steel brake lines
Rear End: Ducati 1100 swingarm, final drive sprocket assembly, wheel, brake rotor and brake caliper, Ohlins shock, GSX-R1100 master cylinder, stainless steel brake line, custom subframe
Frame: modified 1988 GSX-R750
Motor: Kawasaki H2 750 race-tuned by Paul Gast, Fast By Gast Lectron 40mm carburetors and expansion chambers, modified kickstart lever, modified 1988 GSX-R750 fuel tank, custom SCS wiring harness
Accessories: Ducati Imola seat with custom cover, Ducati 1098 fender, modified Gilles rearsets, carbon fiber heel guards, stainless steel hardware, LED taillight, custom headlight assembly, billet aluminum grips, Pazzo Racing levers, SCS chain guard
Paint: Craig Skiver, Craig Paints Bikes
Builder: Santiago Chopper Specialties, welding by Aztek Welding
Owner: Alan Bernard