When I say "swap," you say "Hayabusa", usually. But, today, you say "1970s Kawasaki KH400." That's right, someone took a 401cc, 2-stroke, 3-cylinder ripper and put from a Kawasaki and put it into another Kawasaki from the same era—a KV75.
This thing is bonkers. Just listen to it roaring into life.
This isn't the most powerful big-2-stroke meets tiny bike swap we've ever seen, that award goes to this 350cc Banshee-Grom conversion. But I'd go as far as to say that it's the best sounding, and possibly the craziest, considering a Kawasaki KV75 from the 70s is much smaller and less stable than a modern Grom, and the power gain is so much.
When the KV75 launched in 1971, its 75cc 2-stroke engine pumped out just four horsepower at 6,500 rpm and the torque isn't even worth mentioning. The KH400, on the other hand, lets out a roar as it screams up to its peak power output of 38 horsepower at 7,000 rpm and 28 lb-ft of torque at 6,500 rpm—that's nearly 10 times the power of the standard KV75.
To put it into perspective, a Honda Grom puts out about 10 horsepower, and a stock Banshee is just shy of 40 horsepower. So, as insane as that swap was, I'd feel a lot safer on the Grom than this Kawasaki build, aptly named the "Rocket 400".
Now watch it doing some power wheelies.
When new, Kawasaki's KH400 had a top speed of 101 mph. The question what speed could the Rocket 400 hit, and what rider is brave enough to help us find out? Let us know what speed you think the Rocket 400 would hit flat-out and if you'd give it a go—Remember, it still uses the same milk-bottle-sized drum brakes from the 70s.
