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The cafe' racer was a Brit invention which was very popular from the late 50's into the 70's. The limey's took their vertical twin bikes & cafe-ing them with narrow bars & rear-seat footpegs that required a considerable bend in the knees. These cafe' racer lads loved rock & roll & some say they were really the origin of the word "rocker." Adorned in their black leather jackets, denim jeans & boots they hung around "cafe's" which served only coffee or tea. They would drop a few pence into the juke-box & play their favorite song & blast off into the street or roundabout as fast as they could & attempt to return before the song was played out on the juke-box. Hence the name, "cafe'-racer." Or of course they could race each other & wager on the outcome.

Flash, top on is the baby, bottom one is still in production. The 900 Z-1 for the first year of production (72 or 73?) is quite collectible to this day. Then Kaw went to the KZ models & the Ltd's. & upped the cc's to 1,000. I put carb pods on mine to increase the h.p. Rubber things with filters on top that you had to constantly oil. Increased the air flow. If you did not keep the rim locks in place & horsed the motor the rear tire would actually spin faster than the rim & break the tube stem off. Think she had h.p. in the 80's range.

Z1 is the cult one as it blew the CBs into the weeds, obviously talking UK market here. 1972. DOHC and 903 cc it leapfrogged the CB750

Obviously, Kawasaki’s four would have to be more super than Honda’s, which basically meant bigger and more powerful. About a litre of displacement was envisaged initially, but the capacity actually settled at 903cc, maybe because they didn’t want to scare people too much. While both the Honda and Kawasaki used transverse four-cylinder power units installed in double-cradle frames, the details were rather different. The CB750’s long-stroke, 736cc plain-bearing engine used a pair of roller chains for primary drive, and had a single overhead camshaft running in separate carriers bolted to the top of the cylinder head. The valves were opened by rocker arms, with tappets adjustable by screws. Lubrication was dry-sump, oil being carried in a tank under the side panel, as on a traditional British bike.

Conversely, Kawasaki’s four stored its oil in the sump, and used a built-up roller bearing crankshaft, with gear primary drive. In some respects the bottom end therefore had a few things in common with the company’s two-strokes.

A central roller chain drove a pair of camshafts, effectively running in the cylinder head (in replaceable split shell bearings), opening the valves directly through bucket tappets, with clearances adjustable by shims. Honda’s 1967 CB450 twin had been the first generally available dohc bike engine, but such things had been common in the car world for decades. Most famously, Jaguars had used twin cam XK engines since 1948, and the Z1’s top end was actually quite similar in layout, except that it was cooled by air, not water, of course.

Interesting I'd forgotten the CB was dry sump. Screw tappet not shimming. '1974 Z1B HP is 82

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Interesting I'd forgotten the CB was dry sump. Screw tappet not shimming. '1974 Z1B HP is 82

Flash, Kaw was the super bike manufacturer of the day. Seems like they always misnamed the cc's on the top side while Honda did it on the bottom side.

Back then I got a new bike every couple of years. Had a 73 & 74 750 & a 76 900. Bought the Kaw to keep up with my car-partner's Z-1. The 73 CB 750 replaced my Thuderbolt as posted before. If memory serves me the 73 cost about $1900.

Did you do your own servicing? I seem to remember bucket shims need gauges and special extractors.

Flash, no had all the servicing done at the shop but to my recollection the Kaw needed shims the Honda did not.

You see this is the problem with those incredible performance bikes, everything had to be set up perfectly; The CB 750 was screw tappet but a few had holed pistons through bad valve adjustment. Z1 bucket and shim is much better but you had to dash out and buy the right shim after measuring with micrometer, and of course your replacement shim is not going to match the wear precisely so that's going to be too big or small.....do you throw all the used shims out and buy a single replacement shim?

Then there's carb balancing with mercury gauge......4-6 contact breakers. Or if its electronic that's it isn't it? No adjustment just buy a new one. Access to the middle spark plugs. Air filter.......Don't tell me about clutch - special tools?

With your old twin you can get away with some very sloppy tolerances - not with your 500,000 RPM.

Still at that time cars were going peculiar - see Triumph Stag mechanical injection

Flash, only had to have the valves adjusted a couple of times on my 750's. The Kaw about every 12k.

ONCE IN 12 k GOOD 7500 TO ME. On an older British bike every 1,000, but you do it with plug leaf gauge and 2 spanners in 10 minutes. Hot or cold engine I forget now.

C,mon Tommy you must have had one of these

Some bike, Benelli did one too.

Benelli Sei. That was a 900 a 750 I think

The 900 I seem to think a lot of these fell victim to the rat bike craze of the '80s; matt black and camouflage netting very Mad Max

That is another thing I dislike about Harleys Flash. The chrome & all of the required upkeep other than the Night Train model in flat black which is a lovely machine eh? If you can't clean it with Fantastik it ain't worth having.

Yes I saw a pic of that. One thing would give me nightmares and that's scoring that very expensive black finish on the engine casings

Don't seem overpowered in the brakes department

I still love this one shame it never sold. So what's so different about the night train?

I remember reading the Hells' Angels never bothered with a front brake all you needed do was change down and the torque would stop you. And the mandatory rear view mirror was provided by a dentist's mirror. I don't think to this day they are compulsory in the UK

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