A CZ FOUR STROKE?
SAY IT AINT SO JOE
By Matt Cuddy
Did you know that Jawa/CZ produced (gasp) four stroke motorcycles at one time? Yes, those miserable, complicated oil spewing four strikers.
It’s is truly hard to believe that the once mighty Jawa/CZ factory that manufactured such motorcycle icons as the mighty 1973 Blue tank 400, the red tanked up-pipe 250 and 360, along with a myriad of other winning machines, all two strokes I might add. had once, in a period of a vodka soaked meeting decided on manufacturing FOUR STROKES!?
Yes, those things with valves and all that shit whirring around just ready to break and bring the bike to an abrupt (expensive) halt.
Let’s take a look at what Jawa/CZ offered back before common sense took hold of management at Jawa and sent the four stroke to where it belonged, to the trash bin of history.
The first Jawa unfortunately was a four stroke that displaced five hundred cubic centimeters and possessed an overhead valve configuration, and put out an ASTOUNDING eighteen horsepower.
Jawa chose to name the motorcycle the “Rump” for some reason, perhaps there was someone with a twisted sense of humor in the design department. Here’s a picture of “The Rump.”
The motor was placed in the frame logitud…logitudel…loge…like a BMW, drive shaft and all. It sported a three speed gearbox, with a rigid frame, and the fire-engine red paint scheme that would be the signature color of the marque. I was also a nightmare to service, and had weak valve springs, along with slanted floor-boards that tended to slip your feet onto the tarmac when the going got wet. Jawa produced the Rump for a period of six years, improving on the valve springs, the starter arrangement and the slanted floor boards.
Jawa also produced a motorcycle called the “Wanderer” that was a smaller version of the “Rump” displacing 350 cc’s. It was more reliable than the Rump, and sported real foot pegs, that didn’t fold up, they just bolted to the frame like the ankle breakers they were.
Around 1932, in the great depression, Jawa toyed with a two stroke motorcycle that sported a Villiers 175cc motor, and was a success to some degree, since its low price fit the times when money was a hard commodity to come by.
They also started designing racing machines using again modified versions of the Rump and Wanderer motorcycles.
Jawa did make some beautiful motorcycles around that time, and perhaps the most striking was the 500cc Jawa with hydraulic forks and a plunger type rear suspension. The motor cases were made from magnesium, along with a tower-driven overhead camshaft and four valves. The motorcycle won many club and sanctioned FIM races in the late 1940’s. Look at the size of the brakes!
Also, Jawa seemed to have pre-dated the Japanese in engine design with bikes like the one below. It sported dual overhead camshafts, four valves per cylinder, along with an engine made almost entirely from magnesium. This is a 1955 version named the Z15 that could top out at well over 150 miles an hour.
Here is another Jawa four stroke of five hundred cubic centimeters that took design cues from the Z15, a nice looking motorcycle labled the Type 15.
Right around this time common sense sprung on the scene and Jawa/CZ started producing two cycle machines that were simple to maintain, reliable and fast. Jawa four strokes are a very wanted motorcycle in the vintage collector scene, and a good version of the “Rump” can fetch ten thousand devalued greenbacks. Quite a feat.
We’ll leave the speedway bikes out of this, since they were dominant on the race track for over 40 years, and were, by chance, a four stroke.
Jawa started producing in the early nineteen sixties, the mighty Jawa 90 sport. Look on this site for a full report on the motorcycle. A true six-day mount!
So if you ever see some poor sap on a leaking, smoking Jawa four stroke, just remember it’s most likely worth more than your house for some odd reason. Four strokes, pox.