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 Jamathi

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AuteurMessage
motoholic71



Nombre de messages : 52
Localisation : Lisbon
Date d'inscription : 19/01/2013

MessageSujet: Jamathi   Sam 28 Mai 2016 - 19:51

This is just something that I found interesting enough to share here.
I'm from Portugal and being hit by the latest economic crisis I've been looking into start restoring motorcycles to have an alternative income source in case I loose my job (again!) and for fun of course.
Cutting to the chase, I thought I'd better start small since we had here a healthy number of 50cc manufacture brands from the 60´s to late 90´s due to legislation and these bikes are now (some of them) becoming interestingly valuable and rare.

To get some guidance on the subject I subscribed to a Classics magazine that, though is a national publication it has an international scope, the last month featured the DKW history and the Hollandaise (Netherlands) "love affair" with the 50 cc market which was, like in Portugal, motivated by legislation.

Even though I only got half the brands names featured since this issue only had the 2nd part, it had an article about each one, among them the JAMATHI name (others like Magneet, Locomotief, 28 in total).

So basically what they say is that unlike all other factories in Holland whom had a beginning building bicycles, or were established in the 50's, the Jamathi enterprise started in '65 by co-founders Jan Thiel and Martin Mijvaart who set up shop to basically build a machine to compete in the 50cc Netherlands Championship in which they were so successful that in '67 they went from modifying existing motors to building their own and finally winning the Championship in '68 with pilot Paul Ldewijkx in front of factory racers like Derbi, Honda and Kreidler.

After this the then Kawasaki dealership Brunisma came up with the idea of a production Jamathi, which was released in '71, a 50cc commuter with a sportive character aimed at the home market.
This machine featured a 4 speed Franco Morini motor with a Jamathi top end and slim fuel tank like the racer.
However, it seems that only a thousand were produced despite plans for 2500, due to performance issues, so they say, a venture that ended up with Jan and Martin going back to apparently what they did best, building race machines!

This was almost a quote from the article in the magazine, don't blame me if not accurate!!

I just found very interesting and curious to read about it in a magazine and think that at least this time I have a face to go with the name, and to be able to say that I know and had little interaction with this person is a real treat!

If you understand, I'm not a football fan or almost any other sport really, my heroes are the likes of Walter Kaaden and many other "backstage" enginners like Jan and Frits who dedicated their lifes to build these extreme "no b.s." machines!
So it's a honour to carry the magazine around and show it to my friends and say: "See, I know this person, he replied to my messages!

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Frits Overmars

Frits Overmars

Nombre de messages : 2148
Age : 70
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Dim 29 Mai 2016 - 10:08

Dear Motoholic, I share your enthousiasm for the achievements of Jan Thiel and Martin Mijwaart but here are a couple of remarks in your magazine that require correction. Jan and Martin started cooperating in 1962 or 1963, not in '65.
They built their first complete engine in 1964, not in '67, and Paul Lodewijkx won the dutch TT in 1968, but not the world championship.
Bruinsma's idea to build Jamathi mopeds turned out to be so time-consuming that it probably cost Jamathi the world title in '69. Jan could tell us a lot more on this subject.


Dernière édition par Frits Overmars le Dim 29 Mai 2016 - 12:38, édité 1 fois
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Jan Thiel



Nombre de messages : 477
Age : 78
Localisation : Bangkok
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Dim 29 Mai 2016 - 12:09

Martin and me started working together in 1962.
Our first project was making our own frames, with Royal Nord engines.
The Royal Nord was an ITOM copy, with more space in the gearbox.
So we could fit a 6-speed gearbox.
Our friends Cees van Dongen and his father gave us some help.
Martin won the 1963 Junior 50cc championship.
We wanted more than 6 gears so that I had to design our own engine.
As I had no drawing board I made the design lying down on my knees, on the floor.
Then I made the wooden casting models.
When we first started our engine it was 4 O'clock in the morning.
We tried our bike on the road, the neighbours were not happy....
And we were very disappointed, it was slow!
But we soon discovered that our bearing clearances were too tight.
After loosening them the power was discreet.
We used a Kreidler cylinder.
Later in the year we made our own cylinder, and we got real power!
We did all this in our free time, without any financial help.
When Bruinsma proposed the Jamathi moped idea we thought we would have more time for racing.
But the moped production cost us a lot of time.
So we could start working on our 1969-bike only at half february.
If only it had been ready 3 weeks earlier I am convinced we would have won the world championship that year....
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bubu



Nombre de messages : 5651
Localisation : ile de france
Date d'inscription : 15/02/2011

MessageSujet: Re: Jamathi   Dim 29 Mai 2016 - 17:24

jan, tell us about the racing suzuki spare parts you bought from works mechanics who needed money to go the amsterdam hot streets !
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motoholic71



Nombre de messages : 52
Localisation : Lisbon
Date d'inscription : 19/01/2013

MessageSujet: Re: Jamathi   Dim 29 Mai 2016 - 19:18

Frits Overmars a écrit:
Dear Motoholic, I share your enthousiasm for the achievements of Jan Thiel and Martin Mijwaart but here are a couple of remarks in your magazine that require correction. Jan and Martin started cooperating in 1962 or 1963, not in '65.
They built their first complete engine in 1964, not in '67, and Paul Lodewijkx won the dutch TT in 1968, but not the world championship.
Bruinsma's idea to build Jamathi mopeds turned out to be so time-consuming that it probably cost Jamathi the world title in '69. Jan could tell us a lot more on this subject.

Hello Frits.

Well, that doesn't surprise me, hence my "disclaimer" comment.

All I can say is thank you for clarifying the facts.

I can't however blame the magazine too much, even though their obligation to the readers is to obviously either get the facts correct or shut up.

Being a somewhat recent publication and apparently the only of this kind here and I can only imagine the difficulties of finding reliable sources, this is Portugal after all and they did cover 28 brands just because one emigrant came back home with a couple of Magneet bikes.

I do appreciate very much your input, I like to read about these things as much as the technical stuff, so your testimony was/is priceless.

Thank you very much!
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motoholic71



Nombre de messages : 52
Localisation : Lisbon
Date d'inscription : 19/01/2013

MessageSujet: Re: Jamathi   Dim 29 Mai 2016 - 22:10

Dear Jan I can't say the immense pleasure it is to read about these events first hand, as I find it very entertaining and can only imagine how exciting and demanding at the same time it was to you.
I wish I could witness in person such a project, but whatever details you can share with us are very welcome (I know you must have told the story a thousand times) far from me to bother you so it's at your description.
Funny your comment about the bearings clearance, not long ago I bought a new crankshaft from Yamaha that came with main bearings with a free play well beyond the generic "of the shelf" extra clearance C3 or C4, fact that I remarked to a supposed expert whom promptly said it was low quality China knock offs (even though it was a direct Yamaha purchase and had "koyo made in Japan" marked on them. So much for the Expert!
So I learned something today!

One other curious thing; Many people here think you are the same Jan behind the Casal Huvo project, Casal was the only Portuguese brand left building their own motors, but I know now it was a different person.

Please if you feel like telling any other details about the Jamathi years, feel free to do so, I enjoyed very much to read about it as I'm sure many others. No pressure though

Thank you
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Jan Thiel



Nombre de messages : 477
Age : 78
Localisation : Bangkok
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Lun 30 Mai 2016 - 5:22

Bubu,

At the end of each season Suzuki threw away some scrap material.
A friend of mine, who worked near their hotel, gave this to me.
I have never had any personal contact with Suzuki mechanics.
The last year they were there they threw away quite a lot.
My friend kept all the tyres, sold them, and with the money started his own factory.
Of course I learned a lot from the things I got, but so did Morbidelli, Malanca and Minarelli.
Malanca and Minarelli even raced 125cc Suzuki's resprayed in their own colours!
Morbidelli made his own engine, and so did I....
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Jan Thiel



Nombre de messages : 477
Age : 78
Localisation : Bangkok
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Lun 30 Mai 2016 - 5:38

I never had anything to do with CASAL.
Using C3 or C4 bearings usually gives less friction and more power.
From Hoeckle I learned to change the STD balls for smaller ones.
To make C5 bearings....
Hoeckle provided me with the necessary balls, which are not easy to find.
Of course you can do this only with bearings with an easily removable cage...
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bubu



Nombre de messages : 5651
Localisation : ile de france
Date d'inscription : 15/02/2011

MessageSujet: Re: Jamathi   Lun 30 Mai 2016 - 10:39

thank you for these informations jan - my question was because a dutch friend told me long time ago that somebody bought some suzuki spares from japanese mechanics and that some old suzuki spares went to jamathi to be looked at and that this helped the little team to improve their machines - and your'e right to say that old suzuki machines have been examinated by many non japanese technicians - I was not technician enough to see the differences for ports or diagrams, but i helped a few time barry sheene to work on his 125 machine and I was each time very surprised by the simplicity of this engine, though I was surprised by the needle rollers and bearings I had never seen in other street engines before
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Jan Thiel



Nombre de messages : 477
Age : 78
Localisation : Bangkok
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Lun 30 Mai 2016 - 11:39

There is a museum in Holland, owned by the Toyota importer, that has a Suzuki 125.
Once it was stolen, and someone took it to MZ and Derbi, to have a look at it.
Later it was offered to Kreidler, who called the police...
Of course not without taking a look at it too.....
And the bike turned to the museum, where it still is.
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Marc
Admin
Marc

Nombre de messages : 27688
Age : 60
Localisation : Villiers sur Marne (94)
Date d'inscription : 27/05/2008

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 0:29


_________________
Un p'tit clik vaut mieux qu'une grande claque; c'est Harry qui l'a dit! [Vous devez être inscrit et connecté pour voir cette image]

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http://www.pit-lane.biz
Toop



Nombre de messages : 3486
Age : 19
Localisation : Tours
Date d'inscription : 02/01/2010

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 0:57

It relishes technical details, knowledge generously distributed here. But then the little story that made the big story is delicious, thanks Jan !


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motoholic71



Nombre de messages : 52
Localisation : Lisbon
Date d'inscription : 19/01/2013

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 5:04

So MZ was also keen on peeking at the Suzuki developments.

One can say that it was but fair after the Degner scandal, they weren't doing very well until he turned over to them Kaaden secrets...Almost feels like saying: Boys!...Play nice! Or else...

But then if this didn't happen evolution would be so much slower.

Jan and Frits could capitalise on their knowledge but they chose to help others instead, we are indeed very fortunate to know them!

Feast your eyes
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This is one of yours Jan, correct? would you remember how much power, gears, top speed,carb type,ignition...Sometimes I find conflicting figures searching the net.
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Frits Overmars

Frits Overmars

Nombre de messages : 2148
Age : 70
Localisation : Raalte, Holland
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 11:53

motoholic71 a écrit:
Feast your eyes
[Vous devez être inscrit et connecté pour voir ce lien]
This is one of yours Jan, correct? would you remember how much power, gears, top speed,carb type,ignition...Sometimes I find conflicting figures searching the net.
Here you go, Motoholic. 1971 model, 6 speeds, Bing carb, ignition probably Schummelketel (Jan will know more).
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Jan Thiel



Nombre de messages : 477
Age : 78
Localisation : Bangkok
Date d'inscription : 12/10/2010

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 14:01

4 transfer ports, 27mm Bing carburettor, about 11HP I think, maybe even 12!
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JanBros



Nombre de messages : 228
Localisation : Belgique
Date d'inscription : 05/12/2011

MessageSujet: Re: Jamathi   Mar 31 Mai 2016 - 23:58

I posted these in another topic :

le début de Jan Thiel comme courreur :
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la premiere Jamathi, qui s' appelait Tansini à ce moment  (1964) :
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comparison du 1969 50cc champion Derbi contre sa competition  Kreidler et Jamathi :
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