The '69 and '70 were the Giant Killers! By 1972 they were about 10 HP less. In particular, California had pushed Kawi hard to clean them up, as the crankcases would slowy fill up with unburned oil and fuel from the too-rich oil injection - then the owner would blaze down a freeway onramp and leave a solid grey-white cloud that would leave smears on windshields, because it was so rich and greasy. By 1970, even some Midwest municipalities instituted two-stroke bike bans, due largely to this popular bike (they were everywhere!). They could beat almost anything in the 1/4 mile, but on average they burned out 1 CDI per year, sometimes catching the bike on fire in the process. It was, as far as I remember, the first production bike with a CDI, and boy, it needed it for keeping the plugs clean! But, it was not reliable in their beginning.
The frame geometry was such that stock, from the factory, the rear wheel was 12mm (almost 1/2" !) to the left of the centerline of the front wheel and engine, making miserable handling. This was finally fixed in the 1974 model (I did not work on any 1971-73, so it may have been sooner). The swingarm bushings on a stock, new bike already showed slop on many 1970 ones I saw, because of production tolerance problems.
The first 900-4 model(s) was similar. Kawi struggled with quality back then, for sure, but the bikes had more HP than most in their general class, and were lots cheaper, so they got popular.
When I came to Colorado in 1974, my neighbor had an H1 in Kawi green. I had my first chance to look over their improvements, which included some hoses (like Suzy's) to pull the gunk from the bottom of the crankcases so it wouldn't build up so much, and that stopped the crop dusting tendencies they had. Los Angeles even allowed Kawi to sell them there, after this mod. But the bike was so detuned I didn't even recognize it: the Blue Streak I remember would wheelstand in 1st or 2nd by merely pulling the throttle open to 1/2 or more: it was actually hard to ride in town when it came "on pipe" until you got friendly with it. This show was sharply over at 7500 RPM (redline) because the bearings were not getting enough oil, which I'm sure was why Kawi had the early one's oilers turned up so high. The 1974 model felt like a decent 650 Twin in power, by comparison. And, here in Colorado, most would only start and run well below 8000 feet: many's the time I had to push my neighbor's H1 to get it to start when we were on a ride with others in the mountains, because the compression in the engine was so much lower (to reduce heating and the need for oiling). He always talked about "trading back" to a Blue Streak H1, but never did, as far as I know. Other H1 owners around here rode in groups, and I would encounter them on weekend mountain rides: there were a lot of them out here, through the early 1980s, so they much have gotten more reliable with the detune.
My 750, with my first wife and Vetter fairing aboard, could easily stomp him, which REALLY surprised me! But, that's what became of that legend....