A  History of Classic Racing  50cc Motorcycles


Name: Jan Thiel 

Birth date: 03-06-1940
Birth Place: Amsterdam Netherlands 
Date of Death : Not Yet! 
Place of Death : Not Yet! 
Nationality: Dutch 
Gender: Male

In the late 1950s the 50cc racing interest had begun to grow in Europe and some European riders in from the start included names like Koeveringe, Cees van Dongen, Jan Huberts, Pierre Kemperman and Jan Thiel. Picture of Jan porting a cylinder.

 Jan Thiel, working with Martin Mijwaart, is the man behind the name of the brand Jamathi His name is pronounced at the highest racing level with respect. Valentino Rossi won his first World Championship in 1997 on a 125cc Aprilia machine designed and prepared by Jan Thiel. Picture: Valentino Rossi wins his first world championship.

Jan Thiel's racing career started in 1959 using a self-tuned two geared HMW racer. After this, due to the lack of performance from the HMW an Italian FBM motor was acquired and this was again tuned by Jan. This served Jan well but he was always looking for more power and subsequently speed. As the FBM engine block had no further potential for development it was replaced with a Benelli engine. This became Jan’s racing machine for the 1962 season. That same year, the 50cc class was confirmed by the FIM (Federation Internationale Cycliste Motor), to be a World Championship. Picture left: Jan coming in on the HMW after a race. Right Jan with the Benelli engined bike.

To continue with a story of Jan Thiel and 50cc racing would be impossible without mentioning the names of Martin Mijwaart and Paul Lodewijkx! This talented group of Dutchmen created a racer, with no funding, working out of a wooden shed, and eventually outran the worlds best!  

Motorsport journalist Henk Keulemans followed the team from early on and his book Het Jamathi-team is a very good portrait of the life and times of the trio. Because of the close relationship of the four friends it was some times believed the Henk was one of the funders of the team.  Recently corresponding with Jan, (February 2017) he confirmed that "Henk Keulemans did not work with, or for us from the beginning. He and I became friends after I offered him a test ride on the Jamathi moped in 1970. We still are friends, he is in Sepang now and will visit me Saturday"

Editors note: During the research for this page I have come upon various interviews held with Jan Thiel and media reports. I have, in some cases translated them from another language. I hope I have translated in context.

Jan Thiel, who was born in Amsterdam on the 23 June 1940, was a manufacturer, tuner of engines and supply point for complete motorcycles in the small capacity motor sport world. In September 1962 it was decided that as Jan and Martin Mijwaart had developed a good friendship and had a good collective knowledge of motorcycles and small capacity racing, they would work together. 

Jan commented that "The first joint project was the conversion of a Kreidler cylinder to fit Martins ITOM which, at the time, ran quite neatly. We worked well together because we had a lot of similar thoughts and were able to make good additions to the project. He could do things and I could think things out. I learned a lot from him. 

For a long time we were able to work with each other and we worked well, but, after many explorations into and around the small capacity, two-stroke racing scene and various companies we worked for, he said in 1981 that he wanted his children to go to school in the Netherlands. We were living in Italy at that time and he thought it would be better for them to have a Dutch education. So he left with his family and gave up racing. I think, maybe, that motorcycles were not really his prime objective back then".

"Due to his skill on the race rack with his understanding of the bike and how it worked and felt, Martin achieved good results with his ITOM/Kreidler special on the circuit of Zandvoort, and, as you know, became the co-founder of the 'Dutch Racing Team', which was developed in 1965, and which we later called ‘Jamathi’ with its own breed of racing motorcycles". The Company also built mopeds and race models for road use, also under the ‘Jamathi’ umbrella. Picture: Jamathi 50cc with after-market fairing.

However in 1962 the Kreidler racing motorcycles were not proving so outstanding! At that time, the ITOMs and many ITOM specials won the majority of the races. Cees van Dongen, (1932 – 23 December 2011) became a good friend of Jan's and was at that time a master of the track. He began racing on a DMF which was a converted moped. Picture left: Click for YouTube video of the DMF.

  These engines had no gearbox, only a multiple clutch, but they were very sturdy and reliable, had good tuning potential and a generously finned cylinder and head. They were mounted in a kind of monocoque frame, without rear suspension. I only have an action picture of budding Dutch racer Cees van Dongen, who won all nine races that were organised in 1954 on it!  Cees' DMF had a top speed of 100 km/h. (Quote from Elsberg Tuning)  

"Cees had changed to a Royal Nord with 6 speed gearbox" said Jan, "which was then the fastest 50cc racing bike in the Netherlands. Cees and his father helped us a lot at the beginning, I also learned from Cees' grandfather 'Opa' van Dongen how to calculate a gear box and how to build a shifting mechanism". 

"The ITOM only had a four speed gearbox and so we bought from Andre Huige in Rotterdam a Royal Nord crankcase housing and made a 6 speed gear cluster to fit and also a different crankshaft, I believe. We used a Kreidler cylinder with a home-made cylinder head. With this machine Martin became Dutch Junior Champion in 1961. Suzuki was 50cc World Champion in the years 1962 and 1963 and it was clear to us that we had to do something special if we wanted to get further"!

It was during the winter of 1962-1963, Jan Thiel and Martin Mijwaart began to build their two identical 'Jamathi' racers. Both had equal bicycle parts when they were built and it was then that they chose the engine build based on the the Itom/Kreidler special ridden by Martin.  Again we chose Royal Nord crankcases. Using their friend and fellow rider Cees van Dongen they made another six-speed gearbox. The aerodynamics for the bikes was also provided by Cees van Dongen. Number 5 was for Jan and 52 for Martin.

Question to Jan: 1968 the Jamathi was running at a very high level, so high that she could even win the TT in Assen with Paul Lodewijkx. How did you see this from today's point of view, and what was going on, at such a moment in your mind, when your own machine is in front of a domestic audience and winning the TT? 

"It was completely unexpected, I had assumed that Paul was only playing a little with Hans Georg Anscheidt but never thought he could take the Suzuki. So that was my first feeling, one of complete disbelief, but then, which followed quickly, was a very great feeling of satisfaction".

Paul Lodewijkx after the 1968 TT at Assen Holland

Hans-Georg Anscheidt on the RK67 Suzuki in front of Paul Lodewijkx on the Jamathi. Paul won being 1/10th of a second in front of Anscheidt.

Paul and the Jamathi at a different venue.

Paul on the winners rostrum 1968 TT at Assen Holland

Assen 1968 and the 50cc race. Paul Lodewijkx ( Jamathi ) was the fastest in practice, but initially could not do more than follow the twin Suzuki of Hans Georg Anscheidt . Anscheidt stayed in the lead until the end. On the penultimate lap his lead was about 60 meters. However, Lodewijkx coaxed every ounce of power from the Jamathi and with his skill of highspeed cornering, arrived faster than the German into the last corner, he was also able to use the slip stream of a back marker: result - he finished first, just ahead of Anscheidt. 

It was the first Dutch victory on a Dutch motorcycle since Dick Renooy's on his Eysink in 1948, exactly twenty years earlier. Only a tenth of a second separated Lodewijkx and Anscheidt. Aalt Toersen (Kreidler) finished third at half a minute. Despite the defeat, Hans Georg Anscheidt became world champion in that year, but nobody knew it at the time because the French and Japanese Grand Prix's had not then been cancelled. Some details researched from Wiki

"Of course, we were also very lucky, because our connecting rod bearing (big end) held through, this had always been the weak point. It had already broken in the practice, and a week later at Spa it did exactly that on the finishing line".

"To obtain a TT win or to become World Champions are things that will change your life forever, it's something special and it remains forever in my heart. Later successes rarely gave me such a feeling of complete satisfaction. But I also know that I did not like what followed with the whole press clutter that came to us, with journalists and television shows".

"I was asked: What kind of person was Paul (Lodewijkx), and what were his strengths as a rider? Paul was a very fine person and so was his great family, I was often at his home as a child and it was always very sociable. His brother Reier was able to attend at my departure in Raalte last year, which gave me great pleasure!"

"As a rider, Paul was very good in the fast bends, and despite his size, he was also able to make himself very small and fit in well behind the fairing, and he could also quickly learn new tracks". 

"Angel Nieto told me later that Paul was the only rider he really feared. It is a great pity that he had such a terrible accident at that time, it was never quite the same then as it was before in the Jamathi team. But, as one says, life goes on"

In 1969 Paul had a traffic accident on his motorbike. After a long recovery, he was left with occasional epileptic seizures and his return in 1972 was unsuccessful due to these lasting effects. His new hobby became nature preservation and photography. An epileptic seizure caused his death by drowning in 1988.

Another question to Jan: You were doing a normal job and the development and building of the bikes happened only in your spare time and also with a very small budget. Was it not very frustrating and did you not sometimes think "Oh dear what have I done"?

"From a financial point of view, it was very difficult, we worked four days a week to allow us to have one more day for working on the bikes. Of course, in doing this we also earned less money as our output was down. We paid for everything ourselves and therefore had a rather poor life outside the race bikes and racing. We had no money for clothes or any luxury and so things were tight. I just had a single pair of sandals for my feet and no other shoes". 

How to get to the Shed? "for the ride to work I had bought a Batavus moped for a tenner, the reason for the low price was a broken connecting rod. I seem to think the money for a car was not possible at that time and so out of the question. But we had wanted to do what we were doing at that time and never really thought about the sacrifice. At the end of the season, for example, we sold the old racing bikes to pay for the construction of the new ones".

The team won many races and among its riders were names such as Paul Lodewijkx, Aalt Toersen and Theo Timmer who rode for them between 1967 and 1973 and gained wins in nine Grand Prix races in the  50cc class. Even Cees van Dongen can be seen on a Jamathi.

A Gallery of Jan Thiel and the Team

The Master - Jan Thiel

Jan at the age of fourteen

The Shed with Jan, Martin and Paul

The Four Musketeers of 1967


1963 January - Building a new frame

Intensive work

Jan Thiel at the Drawing Board. The drawing table was any flat surface

Inspecting the bend of a frame tube

Paul works on the Jamathi engine

Moped and Racer on display at the Assen Circuit

Martin Mijwaart working on a Jamathi Moped

Jan and Martin in 1973-their Jamathi

The 1973  Jamathi engine

Jan Thiel on the '74 racer. 50cc Museum Lexmond September 1999

Now! About the Bikes.

The ‘Jamathi’ had the honour of being a home-made 50 cc motorcycle special, which had been built in a shed in Nederhorst den Berg, Holland, that beat all of the works machines in the Dutch T.T. at Assen, Holland in 1968, and in the same year took second place in the 1968 World Championship, piloted by a young Dutchman named Paul Lodewijkx.

BIKEEXIF  There’s something strangely compelling about small-capacity vintage racing motorcycles. They’re stripped to the bone, minimalist and elegant, with not a component or gram out of place. It’s a triumph of function over form, yet the resulting form is invariably pleasing to the eye. This rare Jamathi was ridden by the late Paul Lodewijkx to victory in the 1968 50cc Dutch TT held at Assen. The man fettling the Jamathi in the picture is Geert Keen, who has owned this bike since 1974. After racing the bike for several years, Geert’s throttled back a little, and now rides it with the Classic Motorcycle Demo Team. Picture: [Thanks to Klaas Tjassens. Image © Gert De Weerd.]

After their sensational Dutch T.T. win, there were no fewer than three major motorcycle factories that went after the Amsterdam moped mechanics/ engineers that were entirely responsible for this success. There were negotiations with some Japanese firms, a huge French company and the Dutch Anker-Laura syndication. All were tempting, but they did not give the guarantee that the team could control and specify the development of their own racing machines.

The bike then ceased to be a one-off special and became the riding test-bench for some 2000 Jamathi machines produced for daily road use, but these were an air-cooled version. They were produced along side a much smaller batch of water-cooled 50 cc production racers that mimicked the winning model of the Assen TT. 

Jan Thiel stopped racing in 1966 to fully focus on the design, construction and tuning of the machines for both road and race. His view was that martin was a better racer and he was better with the tools. This proved to be the best decision for the future of the team.

It was at this point that a Dutch Kawasaki-distributor, Henk Vink Jr., stepped in and created a new factory in Amsterdam. In this facility the production of the first series of bikes could begin derived from prototypes that had been developed in the simple country shed and where the "world-beating" machine had been born.

As mopeds in Holland were free of driving licences and road tax, it was obvious that the production Jamathi had to be a moped, appealing to youngsters from 16 to 18 years of age. But right from the beginning of the plan, a conversion kit had been included to enable those youngsters to convert their speed-limited and cycle-path-bound mopeds, in the simplest way, into a real over-50mph motorcycle as soon as they were 18 and able to pass their driving test. It was also found that the more adult buyers also wanted to get the thrill, of the small bike with power and speed and went the route of the Sporterised Jamathi.  

The creation of their first bike, due to the prototypes design, meant that the production Jamathi had exactly the same frame lay-out as the racer which had beaten Anscheidt's Suzuki into second place at Assen.

A moped in name only. The Jamathi cycle parts appear to be capable of withstanding considerably more power than even their own 60 mph, 50cc unit can turn out. It should prove very successful in the world's bantam weight markets. In reality a fully equipped motorcycle; with pedals fitted as a nominal concession to Dutch law. Can the machine, we wondered be started by pedal and crank?

The Jamathi Type 1 had the double cradle frame, built from lightweight steel tube, having a 16 mm diameter and a 2 mm wall thickness, and had the same wheelbase as the racer, but it was made just a shade taller. All the tubing was nickel-plated, and there was no paint on any other part of the machine; petrol tank (9 litres), mudguards and toolbox covers were made of polyester resin with the colour pigmentation integrated into the material.

They chose wheels that were 17 inch with a tyre sizes were 2.50 x 17 for the front and 2.75 x 17 for the rear. These had become a standard in the 50cc racing circle. The hydraulically-damped shock absorbers at the rear had three set-up positions, and the similarly controlled telescopic front forks had cast alloy yokes and bottom fork legs, as on their racer.

The Team Studying The First Moped Build

In reality it was a fully equipped motorcycle; with pedals fitted as a nominal concession to Dutch law. It was designed so that the engine could be started by both pedal and kick-start leaver, this was the MOPED.

Parade of Jamathi Mopeds Outside A Distributors

The cylinders and cylinder heads were made from Jamathi created moulds and were alloy castings, fitted by four studs to the Jamathi crankcase, inside of which turned a crankshaft of their own design. Helicoidal gears transmitted power to a four-speed road calculated gearbox which was based on components purchased from the Italian BM-factory in Milan.

Both moped and pedal-less motorcycle version had foot-operated gear change and a kick-starter. A special device was developed to cope with the pushbike type pedals, that were made compulsory In Holland by the Dutch traffic laws for mopeds. When using the bike with the engine engaged, the position of the pedals was allowed to be different from the normal, opposed pedal, bicycle arrangement. To enable this a control lever was made so that both pedals could be turned parallel and pointing slightly forwards and downwards.

This manufacturing arrangement was designed that way, so that both pedals could be moved to exactly the same position that a motorcyclist would expect to find his footrests! Of course, on the motorcycle version, the pedals were replaced by normal footrests.

With moped speed on the open road in Holland limited to 25 mph, no horsepower output was mentioned for the moped engine, which developed its maximum power at 6000 rpm. The stroke was 42 mm, and the bore 38 mm. On the motorcycle model, the bore was enlarged to 40mm, giving a cylinder capacity of 55cc. Maximum revs were pushed up to 9000 rpm and, with the aid of a 22 mm Dell’Orto carburettor (the moped has a 12 mm unit), 6hp was produced, giving the machine a top speed of over 60 mph.

Because of their own involvement in the racing world, Jan and Martin designed the Jamathi models to be desired by those customers who wanted to go racing and they were manufactured to the standard required.  Converting a moped into a motorcycle involved the very modest amount of money, at that time it was in the region of some 200 Dutch Guilders (about £23) circa 1969, but the price of the complete machine was 1535 Guilders (about £180) as against the moped's cost of 1400 Guilders (some £160). 

Certainly not the cheapest moped/ motorcycle on the market: The ‘Jamathi’ name design was from Jan Thiel who put his initials to those of his colleague Martin Mijwaart and with small manipulation provided the basis of the name ‘Jamathi’. Jan was a man who was not very easily satisfied unless the product was of the highest quality in design and build. . Hence, unlike other mopeds of the period, there was a needle-roller bearing in the small end of the con-rod to support the working of the Gudgeon Pin and of course the six speed gear cluster. If the customer then fitted the racing conversion kit that was available, it turned into a competitive competition bike.

The Assen T.T. winning ‘Jamathi’ was a nine-speed, water-cooled, rotary valve 'stroker'. It was preceded by several years of experimentation, as can be seen above, and continuous track testing through the company’s racing involvement. in the early days using air-cooled cylinders with piston ported induction pre-mix petrol/oil fuel and from these the actual production barrels got their shape. 

Allowing for the large quantity of production models that issued from their new Amsterdam factory, the three, Jan, Martin and Theo soon set up a small series of "Over the Counter" racers, which were derived from the production models but changed from Air to water-cooling for the engine and some other small improvements. Apart from this, the development of the T.T. winning racing special was to be continued and, it was hoped, being backed by the financial support of the road-going business, it would continue to be a success.

Question: If you were looking at a new Jamathi racing engine, how would you begin this? Was this all based on the experiences of the previous year, or were there all sorts of calculations made on the drawing board?

"Some calculations had already been carried out in a coffee shop. We did not have a drawing board available and any drawings I did were mostly produced on Sunday at my home on the dining room table. The drawing material came from my school days. A new engine came naturally from the experiences with the predecessors of the new design, coupled with our new ideas and of course you kept your eyes open to see what the competition was doing!

Question: The resonance exhaust is a component which still remains a mystery for many people. There are already thousands of exhausts in barns and factories where people have experimented and most of them are no better than the original part. How do you get a good two-stroke exhaust?

"First you need to have an existing specimen and then start to experiment. In the course of the years one gains experience and learns what consequences cause an exhaust system to changed. It is, however, a lengthy learning process. Very small changes often make a lot of difference, and in fact, two exhausts made according to the same drawing are not necessarily the same in performance, half a millimetre can easily make a noticeable difference".

Also improvements measured on the test bench are not always are quite often not repeatable on the track, which is often due to the different temperature ratios and atmospheric changes. In the Garelli period I solved this problem to a large extent by putting a fan in front of the elbows during the test run and later wrapping the pipe with an asbestos band on the track. In the Jamathi period, we did not have a test bench, and we use a straight stretch of road, actually the best system, somewhat impractical for our experiments, especially with public transport moving up and down the road.

In 1970 we were on the Sachsenring and the engine was not really working well. We wanted to test the carburettor adjustment and the exhaust stingers on a road section, which turned out to be quite futile in the face of the size of the crowd. I then asked a race official where we could test our racing machine with one ride. To my complete surprise he blocked off a road for us, after a short time the decision was made and Aalt (Toersen) won the race with ease.

We asked ourselves "What caused this change to happen"? The only thing that came to mind was that the lower air pressure had resulted in a loss of performance, which then resulted in a lower exhaust gas temperature, the internal exhaust vibration slowed down and as a result the exhaust system was "too long". Shortening by a few millimetres solved the problem!

How important is the exhaust set-up? Well the following example shows: At Bultaco I simply, out of curiosity, used the Jamathi designed exhaust that was on the test bench which was not for the engine in question and the performance fell from 18hp to ........ 2.5hp!

Question: What was the highest performance ever measured for a Jamathi engine?

The highest measured performance from the last Jamathi engine was about 15hp. This was measured on our roller tester in Breukelen in 1974, but measured on the rear wheel and so one could add, perhaps, another 2.0hp at the engine. Later when we joined the Bultaco race team, with the same engines we developed up to 19HP at the transmission output shaft!

Question: The Jamathi team also worked with Herman Meijer from Laren, did you share with him information about the tuning approach and the speeding-up of engines?

"I really liked the collaboration with Herman Meijer, he is one of the nicest people I have ever met. He made the gears for our engines and also carried out a lot of milling work on the crank cases, our milling machine was too small for this. With respect to his quality, we were still driving the gear trains into  the Bultaco era. It was in this way that Angel Nieto became 50cc World Champion with the gears and wheels from Herman's workshop".

1971 Jan Thiel and Herman Meyer

By the way, Herman also rode for Jamathi. Yes, that was the truth! After the TT in Assen in 1970, Henk Vink did not want Leo Commu to ride the Jamathi and he was actually right, because Leo was far too big and too heavy for the 50s. He wanted to exchange him for Piet van der Wal, the Dutch 500cc champion. We agreed that there should be trials in Zandvoort and I said at that time that a friend of mine, Herman, would also participate in the tests. Vink did not really want this, but he did not refuse. 

Herman Meijer Jamathi Sachsenring 1971


Herman Meijer (Born 17 June 1942) is a Dutch motorcycle racer and constructor who was mainly active in the 50cc class from 1963 to 1975.  As a racing driver, Meijer became national junior champion in the 50cc class in 1964, among other things. Two years later, the senior national championship followed, winning five of the six races. His greatest international achievements are in 1971. That year he drove six grands prix for Jamathi and he finished fourth in the final result, partly due to podium places in Czechoslovakia and Spain.Picture: Herman with Jan Thiel. 

More or less simultaneously with his riding he was a self-taught constructor of racing motorcycles. He started this in the mid-1960s and used the name Hemeyla, a reference to his own name and his hometown of Laren. In addition to complete racing engines, he also built gearboxes for racing in small series for sale. Among his customers were Jamathi and British motorcycle racer Barry Sheene. Meijer was known as a highly skilled constructor. He abruptly retired from the motorsport world in 1975, saying he was done with it.


"So we all went to Zandvoort, van der Wal rode first and as always he went very fast into the corners, but came out of the corner very slowly. This seemed to be his style. Then Herman's turn came and he produced a time that was a second faster at each turn than van der Wal and achieved with his times a lap that was close to the course lap record! Vink had to go back without a place in the team and was not a happy man. Herman, on the other hand, rode the Jamathi at Spa Francorchamps". 

"I have to assume that after this incident, Vink somehow lost his fun of the situation because we did not do exactly what he wanted, and at the end of 1971 the collaboration with his company Bruinsma was ended".

"Through all the circumstances with the Jamathi moped project, we had a bit of technical trouble with the racers, and it was only with the change to Piovaticci that we made real progress again. As for the search for more power, Herman and the rest of us then went back to check each and every one of our own calculations and thoughts on the engine and running gear we were developing. Herman could have gone a long way, but at some point he seemed to have had enough, and had developed a different orientation, a pity, but ultimately, everyone has to do what he wants for himself. Re-uniting with Herman after such a long time period of time returned the old familiar feeling immediately. I was happy to see that he felt the same".

Question: From 1970, Aalt Toersen rode for Jamathi, was that a new stimulus for the team?

"At that time, it became clear that Paul was not able to ride in this year of 1970, and the future looked rather bleak for us without our very good rider. We had not expected Aalt to be separated from the Van Veen team. We also could not know how little Henk van Veen paid his riders and what other things went wrong. So it was completely unexpected that Aalt should want to come to us. It quickly became apparent that a good co-operation with him was possible, and also on the personal level it worked well with him, we have always remained good friends".

"I think 1970 was Aalt's best year as a rider, his victory at Spa after a very bad start was a fantastic thing. At that time we were still making our pistons ourselves, and that was certainly a great handicap for us. I remember the engine running badly at the Assen TT, as a last chance we had an old used piston before the endurance training, as a result Aalt drove about 7 seconds faster per lap and got the pole position! He then unfortunately fell in the race but without serious injury or damage" . 

Aalt Toersen rode for Jamathi. His leathers still show signs of his fall.

In Spa, at the Sachsenring and in Brno we won, and always with that old piston. The Jamathi had never run as well as she did then. We just did not have enough money to have our pistons made by Mahle, as the minimum number of pistons per order was 20 to 30 pieces, invaluable to us but just not obtainable! Later on at Piovaticci such things were finally feasible.

Question: In 1969, you just missed winning the World Cup title again, didn't you silently curse Nieto for his approach to riding (Ulster GP 1969)?

Curse Nieto? No why should I? The racing was as it was and you cannot change that now, and at the Ulster Grand Prix 1969 it was a hard fought race. Yes, they had touched each other and were both thrown to the ground but Nieto had just more luck than Aalt and found that he could continue the race. For us the dream of the World Cup was unfortunately at an end for that year. There were also many more problems for us during the season of 1969.  Our bike was much too late in its development and was really only ready in the early June period also we had a succession of problems with the Jamathi moped project, which took far too much time from us and was costly.

Question: Moving forward a few more years during in which Theo Timmer and Jan Bruins rode for the Jamathi team at the Grand Prix races and the Jamathi era was over". How did you cope with that experience?

With Theo Timmer, we worked together but he wanted to continue on his own developing his own approach and ideas. Martin and I found this a great pity. 

Theo Timmer (born 6 March 1949) is a former Grand Prix motorcycle road racer from the Netherlands. He had his best season in 1981 when he won the Czechoslovakian Grand Prix and finished the season in second place, behind Ricardo Tormo. Jan Thiel and Martin Mijwaart were his teachers. The engine makes he used were Jamathi, Kreidler, Bultaco, He was twice national champion.

We tried working with some one else for another year and that was with Jan Bruins, but that did not go so well as on his side was too much self-interest in the approach. Then at the beginning of 1973, Jan Huberts called me, and asked if I could imagine working for Morbidelli. I asked him if there was an offer for the whole team and he said that only I would be moving over and not the team. I said NO! straight away without thinking, because I did not want to leave the others in the lurch as we had developed a good team. I had previously been given an offer from Minarelli  but that was also only for me alone and I did not accept it at that time.

"In the middle of 1974, I wrote a letter to Gianni Morbidelli asking whether the offer to work for him was still on because we, the team, did not want to continue with Jamathi. I also had a lot of trouble with my father, where I lived. Also my employer faced me with a choice to either spend more time with my job or go full time with motor sport". 

"This was because I was never present on Saturdays and on a Saturday there was always the most work. I decided without hesitation to go for the motorsport, but meant at the same time that I had to live from then on with whatever money I could earn from Jamathi! From today's point of view, I think I would have said that the work was more important but then this story would not make the same reading".

"Morbidelli replied that he had already hired someone else for the position, but a week later I got a letter from Mr. Piovaticci, a friend of Morbidelli, with the offer to work for him, Morbidelli had kindly forwarded our request. We spoke with Eugenio Lazzarini at Assen; this was at the time, he went to ride for Piovaticci, and we went out to be with him to in Pesaro for a few days. Martin and I had never earned more than 120 florins a week in Holland, and Piovaticci offered us 1600 florins a month, as well as a free apartment, and above all we could finally work without financial problems. The decision was not really easy for me, and I regretted it at the time, but continuing with Jamathi was simply impossible given the overall situation".

Theo Timmer and Jan Thiel

The Jamathi Team Jan Thiel, Theo Timmer and Martin Mijwaart

Theo Timmer with Jan Thiel and the Jamathi

The Water-Cooled Jamathi Engine

Question: Before we come to the Piovaticci period, I would like to know what you believe was the best moment of your time with the Jamathi Equipe?

"The most beautiful moment of the Jamathi period for me personally was the victory that Paul Lodewijkx won in Brno when we were without television and journalists. We had a few really difficult weeks behind us, but the engine, with some tender care was then really brought back to being on the gas and running well! However at the circuit we had been directed to the "wrong" paddock area in Brno . 

There was usually a separation between Western and Eastern bloc participants and we arrived late in the night in Brno and did not know (luckily) that we had to be in the allocated paddock. So we pitched our tents just wherever there was space. We were in the Eastern bloc paddock. The next few days we found were so interesting that we kept mental notes for later, also it was great fun because we met a lot of new people with new ideas. The Czechs had really nice bikes and had many self-made machines which we found very interesting. They had tried approaches that we had not, thoughts for the future perhaps?. I was then with Olda Fiser, who was right next to us, and we remained friends and communicated until his death".

Other very nice moments were of course the win of the TT in Assen and the fantastic victory trip of Aalt in Spa, after he had started so badly (never say die). The biggest surprise, however, was Theo's victory in Hockenheim in 1973. Martin and I had already driven back to Holland to make new cylinders for the next race in Monza. Theo called us from Germany and it was in that way we learned that he had won the race".

Back to 1969, there was then a great possibility that the support from the Jamathi Mopeds would have enabled the continued development of the 125cc racing ‘Jamathi’, a prototype of which had existed for quite a while but had not been brought to the race track. But at this time in the company's development this model stayed asleep.

The ‘Thiel team' quickly developed into the most popular manufacturers in the lightweight class in Holland and the rest of Europe. They were also well viewed by the Japanese. Many of their ideas were incorporated into other manufacturers’ race bikes. However, due to lack of money which would allow Jan to continue the Jamathi project, he left Holland for Italy in 1974.

The designs of Jan Thiel are characterized as highly innovative, fast and reliable, both in terms of power and in the chassis. He was one of the first to experiment with a one-piece frame, labelled 'of monocoque construction'.

Monocoque, also structural skin, is a structural system where loads are supported through an object's external skin, similar to an eggshell. The word monocoque is a French term for "single shell" or (of boats) "single hull". A true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load carrying internal frame.

Further information on the Monocoque: (Researched from Jan and Elsberg Tuning) 

Jan Thiel "The main reason for making them was that they were very narrow, giving an aerodynamic advantage, they were very stiff and handled very well but they were very difficult to make. The frames were identified by year, usually we made one new frame each year using last year's experience. The first monocoque was made in 1972, it handled very well but there was a problem with the engine. For 1973 there was a new frame and engine, and this engine, with a second one made in 1974 later became Piovaticci and Bultaco"

"In 1974 two frames were made and at the end of the season. One complete bike and the engine of the other bike were sold to Piovaticci. The second frame was sold to our friend Juup Bosman and fitted with a Kreidler engine. Our colours in 1974 were blue and yellow. I don’t remember why"!

Nigel Stone of the UK, bought 3 bikes from the Jamathi team, first a 1965 type, later a 1970 bike which was Martin's bike (now owned by Dik Toersen), and later still he bought the 1971 bike now owned by the 50cc museum. He won a lot of races in England and was probably the most successful Jamathi rider.

When Piovaticci could not go on racing at the end of 1975 we had to wait some time before starting work for Bultaco. In this time Martin made a new frame for Juup Bosman in stainless steel with a Kreidler engine fitted. Juup won the 1974 national Dutch championship with the 1968 bike he had bought from us.

Theo Timmer made some monocoques of his own and Cees van Dongen also made one, with Bultaco production racer engines. Many people in different country's made 50cc racers with monocoque frames, it became a fashion for some time."  Jan Thiel 2009. Picture: A 1970 Jamathi, non monocoque Race Bike seen in a Parade in 2010.

Although not part of the ‘Jamathi’ story, the following is worth reporting as it concerns the Father of the ‘Jamathi’ family and his story. We do still however have to cover his involvement in the development of the race bikes for Piovaticci, Bultaco, Minarelli, Garelli, Agrati, RUMI, Schuurman 250cc Kart (four-stroke) Engine, Aprilia and Derbi.

A Time line of a career in Motorcycle Development. 

1959 - 1960 Starts 50cc Racing on the HMW 50cc
1960 - 1962 Changes bike to the Italian FBM 50cc
1962 - 1963 Moves to a more competitive Benelli 50cc
1962 - Begins the friendship and collaboration with Martin Mijwaart
1963 - 1964 Rides a Royal Nord 50cc
1964 - 1965 Changes to a Tansini 50cc
1965 - 1966 Starts racing the Jamathi 50cc
Jan stops racing and decided to concentrate on building the Jamathi name, its road bikes and more important to him, The Racers.
1966 - 1975 Worked at Jamathi
1968 - Jamathi ridden by Paul Lodewijkx who wins at the Assen TT
1975 - 1976 Moves to Piovaticci 50cc and 125cc
1977 - 1980 Moves to Bultaco 50cc, 125cc, 250cc. (4 times World 50cc Championships and 1 time World 125cc Championships)
1980 - 1982 Moves to Minarelli 50cc and 125cc. (2 times World 125cc Championships)
1982 - 1991 Moves to Garelli 50cc, 125cc and 250cc.  (8 times World 125cc Championships)
1991 - 1992 Moves to Agrati 125cc and 250cc
1992 - 1993 Moves to RUMI 125cc
1993 - 1995 Moves to Schuurman 250cc Kart (four-stroke) Engine
1995 - 2005 Moves to Aprilia 125cc and 250cc. (4 times World 125cc Championships and 6 times World 250cc Championships)
2005 - 2006 Moves to Derbi 125cc
2006 - 2008 Moves back to Aprilia 125cc and 250cc

In March 2008, after more than 42 years of being in the racing scene, Jan announced his retirement from the racing community during a reception that was held during the Jamathi Club day. He and his wife moved to Thailand where they still enjoy their old age. He is a friend of mine and I value his fellowship.

The Years After Jamathi.

Jan, collaborated again with Martin Mijwaart when he asked him to joined a new team. This was to build a winning race bike for the then, Italian top rider, Eugenio Lazzarini. This racing machine was called The Piovaticci. A following page will show how all of the knowledge and skill, that he had amassed at this time could be transported to another project and manufacturer and show great results.  As he never stopped learning and at times failing and overcoming those failures, his pool of experience grew and is legendary.

The Copies and Replicas of a Jamathi

Jan Thiel has his own views on these bikes. 

A factory made Jamathi racing 50cc motorcycle is now widely sought after and as few of the factory bikes remain many replicas have been created. "They follow the basic principles of the factory but are new manufacture. The problem with completing a true replica is in finding the correct Jamathi engine, which was the heart of the motorcycle. As a result other manufacturers engines have been used. One trend is to use the Minarelli P6 engine. This completes the package but it does not make a true copy even though people name them 'Jamathi'. I do not countenance this approach and would like it to stop".

An example of this is in the detail of an auction write-up as follows:

Jan Thiel, Martin Mijwaart, and Paul Lodewijkx! are a talented group of Dutchmen who created a racer, with no funding, working out of a wooden shed, and eventually outran the world’s best! The team won many races and among its riders were names such as Jan Thiel, Martin Mijwaart, and Paul Lodewijkx, are a talented group of Dutchmen who created a racer, with no funding, working out of a wooden shed, and eventually outran the world’s best! 

The team won many races and among its riders were names such as Paul Lodewijkx, Aalt Toersen and Theo Timmer who rode for them between 1967 and 1973 and gained wins in nine Grand Prix in the 50cc class. 

This 'Jamathi' is a competitive 50cc race bike with a high spec engine including rotary disc inlet and special cylinder and head. The engine base is a Minarelli P6, but much modified with very few components left untouched producing a remarkable 18bhp from a 50cc motor and the bike will shame many 125s and 250s.

The bike has spent several years in a private collection but could well be a contender in the current 'Classic 50 Racing Club' championship events. The vendor has a large spares package that includes a spare engine and many useful racing set-up parts. These will be offered for sale separately to the successful bidder.

Comment from Jeep: This bike carries on the screen a small sticker indicating '50' and 'Hans'. This refers to a Dutch rider who was a friend of mine, Hans van Bregt.  He is now unfortunately not with us as he succumbed to injuries received during a race at Gedinne in Belgium.   

Frank Melling wrote a good article about Hans for an American magazine in March 2015. You will note that the only change made to the bike since the previous pictures is a change of cylinder head and barrel.

To continue this story will take a few more pages.

These are in the process of being written and will be published as soon as possible.

The Piovaticci Period        UNDER CONSTRUCTION



Minarelli Involvement    UNDER CONSTRUCTION



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