50cc Racing History from 1953 through to 1983 - JEEP (AKA  J. E. Elton-Payne) 
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High-tech, Low-tech from this Czech

(Research included an article in Classic Racer with additions and comments from forums and emails., Where the article has generated discussion on Facebook it allowed valuable information to be added. My Thanks to Peter Dobson, Motorcycle journalist, who provided the basis for this page and also to Lukáš Hromádka for his observations and additions.)

This page was first posted at the beginning of September 2018. Since its posting I have had numerous messages from people from East and West Europe pointing out missing data and some inaccuracies in the story on the ‘Larner JAWA’. I cannot change the article as written but I have made comments and additions on the fly and secondary pages. I hope that the new posting gives a fuller and more accurate read. Jeep.

The JAWA / TATRAN 50cc Racing Motorcycle: Peter Dobson tracks down another unusual little racing 50. This JAWA/TATRAN is something of an engineering enigma with ‘spiritually uplifting’ points and other areas of pure bodgery.

Terry Larner sits astride his 50cc JAWA racer, he collected it from Czechoslovakia strapped to the roof of his car

DISPITE their impressive off-road record, JAWA do not have a reputation for fine engineering. Nevertheless, Terry Larner’s 50cc JAWA racer is exquisite, a credit to the Czechoslovakian firm.

Formed in 1929, Jawa started racing in the early thirties with bikes designed by Englishman George Patchett, Brooklands rider/tuner of McEvoy JAP vee- twins. George went on to even greater things when he returned to Britain upon outbreak of War and designed the Sterling sub-machine gun! Jawa were taken over by the state in 1945 and returned to racing two years later with un-supercharged and supercharged dohc twins.

Comment received from Martijn Stehouwer, who lives in Deurze Holland and is the Owner of EMOT Racing: "The first lines of the article about Jawa not being known for fine engineering are a bit misplaced. Jawa was in its days a big engineering name, with box loads of patents on motorcycle engineering. Even Honda paid to use Jawa patents, in fact, I think they even outsourced some developments there...(Honda's first two-strokers are full of engineering details that are common in Jawa-CZ products")

The 50cc racers were introduced in 1964. There were three (perhaps four at the most), all built by Povazske Strojirny Np Povaz ska Bysterica, the unpronounceable subsidiary responsible for all of Jawa’s ultra-lightweight bikes and mopeds. All were slightly different, suggesting they were made for individual riders. Purely works machines, when raced in Czechoslovakia they were known as ‘Tatrans’ in red and white or blue and white. All colours were present on the tank and frame of Terry Larner’s JAWA/TATRAN.

The model that Terry rescued had a 1964, 5 speed gearbox. This is identified by a smooth contour to the casting behind the cylinder. In January 1965, a 50 cc 'speed' motorcycle with a 6-speed transmission was introduced, the engine of which was based on an off-road design. It was the first in a series of successful, bespoke TATRANOV 50 RS racing motorcycles. The casting behind the cylinder on this engine has a small bump inline with the gearchange mechanism  

The 5 speed engine

The 6 speed

 

The top photograph is Terry's JAWA 50cc 1964 Disc Valve as displayed at the Lexmond Museum. Bore and stroke of 40 x 39.6mm and a compression ratio of 14.5:1, 10bhp at 13,500rpm, 5 speed gearbox giving a top speed of 90mph. The smooth contour of the 5 speed crankcase is evident. 2nd photograph: Certainly the massive six-plate clutch, with its complex built-in shock absorber would have no trouble with that sort of output. Terry says it would do justice to a good 250!  


By comparison this is the clutch Honda used for the RC113 of 1963 with the  change to a 4 valve DOHC engine, 49.61cc, bore 33.0mm x 29.0mm stroke, listing over 10bhp at 19,000rpm, transistor ignition, 2 carbs,( piston valve), wet sump, 9 speed gearbox, 53kg machine weight, front brake a push bike calliper type, rear 2LS drum, 2.00-18 front and 2.25-18 rear tyres, max. speed over 140kph (87mph).

Terry is dedicated to preserving ANYTHING to do with 50cc racing and he heard about the Jawas in 1977, by which time they had been sold to private owners. He arranged to buy one through a man in Prague, collecting it from Harold Merkel, the German 250cc road race champion, at his motorcycle shop in Bayreuth near the Czechoslovak border.

The little racer was strapped to the roof of the car for the journey home — a risky business for Terry and his two companions with a gale blowing, pouring rain and NATO manoeuvres going on all around them. Unlit tanks and lorries thrashed past them along the autobahn in clouds of spray and, just to add to the excitement, the bike came loose and nearly fell off the roof! Mind you, the JAWA was already a depressing mess as somebody had crashed it in a comprehensive way. 

The bike had obviously cart wheeled and caught fire, melting the front brake plate. Not surprisingly, the frame was bent, the exhaust pipe flattened, and the tank badly crumpled. In addition to all that, everything was totally clapped out.

TATRAN or JAWA?  In further research of the information contained on the pages in Classic Racer, I have found that there is a lot of confusion on the internet as to ‘what is what’ in the ownership and the manufacture of the bikes. From this research it appears that the Jawa concern never made a complete 50cc factory racer themselves. However, the JAWA 90cc two-stroke engine was a very popular engine which lent its self to down-sizing and good tuning and was popular with the racing fraternity for use in the building of 50cc race bikes. (See pictures in the gallery and also the TATRAN page)

TATRAN 50cc

JAWA 50cc

Whatever the badging on the motorcycle, the frame, engine and almost all other parts are the same as the three Tatran racers built by the Povazske Strojirny factory who were a supplier of parts to JAWA but not a subsidiary. The attached page gives a fuller picture of the Tatran and its development and successes.                                                                     Click here

Terry wrote to the Czech embassy in London asking for details of the bike. There was no reply and he finally lost patience and complained to the Czech government. One year later came a friendly letter from the embassy stating that the JAWA had ‘won a number of national races and achieved some good results in International events in Austria, Yugoslavia and the GDR’.

Apart from a few snippets, such as; it had a six-speed gearbox (when it actually had only five), the carburettor was a 22mm Jikov with a Dell’Orto float chamber (which he already knew), that was all they were prepared to tell him. Their reticence was probably due to pressure from the ‘powers that be’ in Prague who seemed resentful that he had the bike at all. But for Terry’s efforts the JAWA would have gone for scrap.

He discovered that the disc-valve engine has a bore and stroke of 40 x 39.6mm and a compression ratio of 14.5:1, the factory claiming 10bhp at 13,500rpm which gave the JAWA a top speed of 90mph. That equates with the power/performance ratio of other racing 50s of the time. 

He also says the engine was a tool room job that must have cost a fortune to produce. “All the bits that matter are spiritually uplifting to an engineer,” he enthuses, but in the crash the forks had hit the crankcase and separated the vertically split halves, buckling the mating faces, breaking off a crankcase fin and wrecking the distributor.

The restoration was a lengthy, bloodstained business, only recently completed. “I had to ‘fight it’ all of the way.” The crank cases were warmed and straightened out beneath a powerful press — a very ‘dodgy’ operation. Then he machined the faces, taking five to seven thou off both. That meant relocating all the spigots and shortening the crank shaft and the gearbox shafts to fit the narrowed space. Incredibly, the engine is a runner, but after all the modifications and total lack of spares Terry has no plans to race the bike.

The ‘upside down’ forks, frame and rear suspension units were made specially for the racing 50s — there was nothing available to bolt on in Czecho, partly due to a lack of western currency. The forks had come off second best in their collision with the engine and Terry had to make new yokes in Dural and a set of stanchions in high tensile steel. The sliders and the dampers are the originals.

The 18 inch wheels were standard items from production lightweights, shod with narrow tyres (2.00 front, 2.25 rear) running at surprisingly low pressures — around 17 and 21lbs respectively with the average sized ‘jockey’.

Much work was needed on the tubular frame, the correct geometry finally being restored by putting an iron bar through the head tube and applying plenty of heat. “It would have been much quicker to have made a new one!” said Terry. The swinging arm showed signs of having had a set of lugs hacked off and was probably constructed in the JAWA race shop from spare tubing.

The smashed alloy rims had to be replaced but they were useless anyway. They had been drilled oversize and washers placed beneath the spoke heads to crudely re-align the wheels. This was probably the work of the same unsympathetic soul who’d raced the bike with the engine unsupported by the cylinder head mounting bracket! Terry used a photo of another works bike to make a bracket. (Terry made a matching plate to act as a hanger for the Del'Orto float chamber)

The melted front brake back plate with its cast-in pattern was easily replaced by anew one off the shelf. By all accounts the brakes were very good despite their humble origins, but, then, they weren’t unduly stressed by the little 110lb machine.

The 1966 front brake was a standard item for the JAWA lightweight road bikes. As the 50cc race bike developed throughout the European continent it was decided to move to more lightweight, stronger metals and the example opposite is of the 1971 magnesium variety. A move to disc brakes came later. (JEEP)



Czech engineer Tichy (who at the time was developing new racing two stroke twins and fours) had a hand in the design of the 50 and Terry reckons the JAWA and its sisters were either mobile test beds for the larger units or prototypes for the more sophisticated 50cc racers which appeared later. These had similar power units in twin loop cradle frames and wheels with magnesium brake drums.

“The engine,” Terry says, “is light years in advance of the rolling chassis which is primitive in places — the footrest stays are strips of steel. But the ratchet filler cap, in contrast, is a work of art. It is interesting to speculate just how JAWA might have changed the course of post-war motorcycle racing history had the race shop not been starved of money and materials.”

The factory of Povaszke Bystrica, well known for their supplying of the JAWA 50 lightweight motorcycles and MANET scooters, is engaged in the production and development of machines up to 250cc cylinder capacity. This picture shows their 1964/65 road racing model of the 50cc and 75cc classes without enclosure, bearing the name  JAWA-CZ but using the TATRAN running gear and their 90cc engine sleeved to the required size. TATRAN is also their brand name, for their 125cc standard scooter.



Terry's JAWA 50 1966 at Lexmond by Göran Kähler


This is a  very good restoration of a mid 1960s TATRAN 50cc racing machine.  This has the air-cooled engine similar to the Terry Larner model but with 6 speed gearbox. The small hump behind the gear change arm shows the difference. The frame is of a different construction showing, for example, a modified top tube design. 






A Gallery of JAWA - TATRAN racers.

1965 TARTRAN - 1

1965 TARTRAN - 2

1969 Water-cooled, dry-clutch, rotary valve, reverse cylinder Tatran road racer. (Works)

A-TATRAN-5 speed with Disc Brakes Lexmond Museum 

EMOT-Tatran with factory 5 speed racing engine and Emot chassis

Emot-Tatran 5 speed in action in the European 50cc championship ,2013

TATRAN 50 RS, factory version, Tatran Zbynek Havrda, Bedrich Fendrich

Tatran 50 GP, year 1970, 15 bhp at 14500 rpm 

TATRAN 50 RS-1

TATRAN 50 RS-2

TATRAN 50 RS-3

TATRAN 50 RS-4

 TATRAN - JAWA 

Lukáš Hromádka 

 

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