Ten days with a 1975 Kawasaki S3 Mach 2

The Classic Experience

| January/February 2008

Kawasaki S3 Mach 2
Years produced:
Claimed power: 42hp @ 7,000rpm
Top speed: 97mph (period test)
Engine type: 400cc, air-cooled, two-stroke inline triple
Weight (dry): 155kg (339lb)
Price then: (1975) $935
Price now: $1,000-$2,000
MPG: 22-35
Oil consumption: 1/2qt two-stroke oil during test
Beginning miles: 2,925
Ending miles: 3,283

If you’ve never ridden a classic two-stroke, you owe yourself the experience. Generally smoky, smelly and loud, they pay back in spades with a power rush you have to feel to appreciate. And that’s just with a healthy single: multiply that count by three and the payback is a thrill a mile.

We sampled a 1975 Kawasaki S3 Mach 2 - one of the tamer (and better) of Kawi’s three-pot oil-burners over the course of a few weeks - and when it was all over, we hated to give it back. Our test bike is the kind of machine we all dream of finding. Its first owner rode it a little over 1,000 miles before passing it along to his son, who then parked it in his garage where it sat until 2006. Its current owner then acquired the bike for $150. Yes, just $150. But more on that later. 

In the beginning…
Before 1969, Kawasaki was a just a bit player on the American scene. With a quirky line of two-stroke singles and twins, its biggest standout was its BSA-clone W1 and W2 650 twins. But that all changed when Kawasaki introduced the three-cylinder Kawasaki H1 Mach III in 1969. With a claimed 60hp from its 498cc three-cylinder, two-stroke engine, it was just the thing for a power-hungry market. Suddenly, Kawasaki was no longer an also-ran; the Mach III’s 120mph top speed and 0-60 time of 4 seconds made it the king of the drag strip and the fastest production motorcycle on the market. And the market loved it.

Quick to capitalize on the Mach III’s success, in 1971, Kawasaki duly introduced a trio of triples focused on that bike’s two-stroke theme. First up for the new additions was a bigger and badder 750cc variant, the Kawasaki H2 Mach IV, followed by the 350cc S2 Mach II and finally the diminutive 250cc S1 Mach I, all sold as 1972 models. 

Not surprisingly, the 500cc and 750cc triples garnered the lion’s-share of attention from magazines and riders alike. And yet, the little 250cc and 350cc models, almost forgotten today, were stars in their own right — especially the 350 Mach II, which morphed into the 400cc S3. 

The Kawasaki S3 — the best of the bunch
While the 250 Mach I changed little in its production life, Kawasaki continuously developed the 350. In 1974, it became the Kawasaki S3 Mach 2, its engine enlarged by 50cc to 400cc and, most notably, rubber-mounted to a new, strengthened frame. The earlier 350 was already considered the best-handling of Kawi’s triples, and the new S3 was even better. "This is one Kawasaki that can be stuffed into a corner with lots of confidence," Cycle World said in its January 1974 issue. "It can be flicked from side to side, power on, except in the first two gears. In that situation you have to ease the power on to keep the front wheel down. If it had a little more power, production racing the 400 could be lucrative."

Ronnie Vance
8/11/2011 9:41:01 AM

I detected a slight "dis" on the earlier Kawasaki 2-strokes. I had a '71 A1SS 250 Scrambler that I still miss. I have had a lot of bikes since that one, but it was the most fun to ride.

7/22/2009 8:03:40 PM

Great write up !. This brought back a lot for me since my first bike was an S3 that I spent my senior year in highschool salvaging form the prior owner's LOLA (loss of lubrication accident). A new crank cost $339 back then, which was the best way to go since no one could rally press the crank apart. 3 sets of points - people don't even know what I'm talking about nowadays! Another problem was the plug cables: I nearly got killed by a semi when I got caught on the Chesapeake Bay bridge in a rainstorm and the cables shorted in blue sparks to the cylinder head. The bike really took to a set of expansion chambers - I can't remember the manufacturer - it must have added about 20% power on the top end. Keeping the wheel down was a chore. Handling was OK, especially after changing the shocks, but the centerstand hung down too low and led to at least 2 wipeouts on turns. Also, going from 22 mpg to 33 mpg is a 50% improvement, not 33%.

6/2/2009 2:54:57 AM

What a blast! Sounds like you really enjoyed the bike. I've loved restoring a 1974 S3, and just posted it on ebay (item number 150349176339, ending 7-10-09). Thanks for the tale!

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