1.000.000 Jawa 634s. There are quite a lot, right? The Jawa 634 was made for around ten years and that was actually in the days when the people of Jawa were no longer allowed to do the things they did best: Making very progressive motorcycles.
Jawas for the Russians
Because Czechoslovakia was on the Russian side of the Iron Curtain. Creativity was therefore restrained in an old communist way and according to the economy plan large numbers of simple things had to be made to raise the masses. Of those fat 1.000.000 Jawa 634s, such an 500.000 went to Russia, and most of them are still driving around now. Because giving basically good machines to people who have become emergency improvisation specialists, that guarantees very long lifetimes.
A sidecar compatible frame
The basis of the 350 cc Jawa 634, that is the then modern, rigid double cradle frame with a stably mounted headset and a wide rear fork bearing. This laid the foundation for using the Jawa 634 as a serious sidecar machine. The suspension and damping were good. Under the saddle was - again, so practical - a spacious compartment for the storage of tools and spare parts. After folding up the buddy seat, the battery and the voltage regulator were easily accessible. The Jawa had light alloy drum brakes, the front of which was double acting. The wheels themselves were light, but strong enough for sidecar use.
The engine block
The 350 cc twin of the 634 was 'more of the same'. A two-cylinder two-stroke with piston-controlled flush. But there was already a lot of experience in that block. The connecting rods had caged needle bearings in the big ends while loose needles were turning in the small ends. The primary transmission went in oil bath with a duplex chain, the characteristic combined shift pedal / kick starter was on board, as were four gears and a closed chain case for the secondary chain. An 75 W direct current dynamo provided enough power for an 35 / 35 Watt headlight, flashing lights and a pretty serious horn.
Modern times
After the 634 came the ... 638. At Jawa, the improvements went step by step. But the principle remained that the engines were reliable and easy to maintain. That is why the Jawa 1984 was introduced in 638. It had no cast iron, but aluminum cylinders and the space between the cylinders was increased for better cooling. In addition, the 638 has an alternator.
The popularity
Peraks, Ogars and the early 350 cc Jawas with their small wheels and a lot of sheet metal, these are quite popular nowadays. And instead of over 'a few hundred euros', there are already amounts above the 4.000 euro for attractive copies. Not to mention the rare 500 cc OHC four-stroke Jawas for which more than 25.000 euros are being requested.
Not yet discovered
Jawas from the 634 generation have not yet been 'discovered'. They may be less classic, but they are extremely dated and very employable. And affordable. Think of amounts from under the 1.000 euro for something that you can best make something nice to something less than 2.000 euro for a topper. Their weakest point is the chrome work. But that can still be obtained through various Polish, Slovak and Czech providers. And that smoke? Ah: with a modern mineral oil you can mix 1 on 40. That gives no problems and only minimal smoke. And if you have an 634 with a separate 'Oilmaster' oil supply, then there is no problem at all.
