The W1 may look like a copy of the BSA from the early 50's. Especially compeering the engines. A quick look at the engines and you may think they come from the same brand just another years production.

But Kawasaki did a lot of work with the new W1: First of all its not leaking oil. The BSA and even the K1/K2 used two piece con-rods and plain insert type bearings. Kawasaki made a big improvement bye using ball and roller bearings all over and one piece rods and a one-piece pressed crankshaft assembly The lubrication was still dry sump but Kawasaki paid more attention to the ventilation and oil flow to improve reliability. Another important improvement was the oil filter incorporated in the right side cover. The "new" engine was enlarged to 624cc, still only one carburetor was fitted, a Mikuni VM 31mm. The compression was 8.7:1 and maximum power was 50 hp at 6500rpm. Not much, but a lot more then the BSA produced.

All over the W1 was much better then the BSA or K1/K2 bikes.  But the gearbox was not up to the standard f the engine. The gear-change smoothness and precision was far from satisfactory. Anyway this was changed already in 1967, se below.

W1 1966-1968: 

The W1 was launched in 1966 as a 650 (624ccm) street bike.  One 31 mm carburetor and 50 hp at 6500 rpm. The bike was quite good-looking with much chrome and a classic look (even then) Testers back then found the handling good with excellent brakes and satisfactory performance. Cycle World measured the bike's top speed to 162.5 kph and the quarter mile in 15.6s with a top speed of 136.7 kph. The colors available was black, candy red and candy blue. The bike is easily recognized by its single carburetor and instruments incorporated in the headlight. The instruments were a one-piece affair placed on top of the headlamp shell like the 250 Samurai. A twin leading front drum brake was used with a single drum unit rear. The indicator flashers were an optional extra.

In 1967 The W1 got the same gearbox improvement as the W2SS (se W2SS below). In 1968 You could have your W1 with a two tone seat cover. Total produced was 3282

W1SS 1967(-?) First version, one carburetor

The W1 didn't sell as much as Kawasaki had hoped it would. So to boost sales they made a more sportier version., the SS.  Kawasaki  changed the exhaust muffler structure & shape. The exhaust where shorter and so where the front fender. The rear fender stay now incorporated a small grab handle and the saddle vas reshaped. On the side panel there was a nice 650SS sign. Like all W's from 1967 the gear mechanism was improved for more accurate gearing and the front wheel was one inch bigger, now 19inces. Power and performance was the same as for the W1. This is a quite rare W model sins only 251 bikes where made.  Note this bike has only one carburetor. SS stands for Street Scrambler

W2SS 1967-1970

The W2SS was made to boos sales in the US. The W2SS is much the same as the W1SS except one significant change. It got twin Mikuni 28mm carburetors replacing the original single 31 mm. This resulted in a new cylinder head. The intake valves was upped from 36 to 38 mm and both the intake and exhaust valves was redesigned for better cooling.  The engines compression ratio was up to 9:1 from 8.7:1. Power was up 3 hp to 53hp, this was archived 500 rpm higher in the rev range. (7000rpm). Other changes compared to the W1 was one inc bigger front wheel now 19inc, the exhaust mufflers  and fenders was smaller. Performance was better: Cycle World clocked top speed at 180.2kph and a 14.5s quarter mile at 146.4kph.

Like all other W1, W1SS and W2 etc, the gear box was improved. The earlier model was well known for its lack of smoothness and precision of its transmission. This cause of female and male gears trying to engage each other running at different speed. Resulting in missed shifts and a noisy gear shift. This was totally eliminated from 1967. This cure was a use of the engagement of knobs or dogs, into holes of the corresponding female gear. The female gear had six holes to the males three knobs resulting in a much improved transmission.

In 1969 the chromed gas tank was dropped in favor of a painted one. (at least in the export version) Instruments were separated from the headlight the headlamp was changed as was the headlamp brackets.  The bike was now given a new name, the 'COMMANDER'. Color options were Candy Black, Blue or Red

1969 W2SS Production for export to the United States in 1969 produced 639 units of vehicles.

W1S 1968-1970