Tuesday, February 7, 2012

The legacy of the DKW RT-125, the origins of an industry?

I've been amused by all the bikes that were derivatives of the DKW RT-125. Most recently Yamaha produced a concept bike, the Y125. This is an imitation of their first motorcycle, the YA-1. And that was a copy of the legendary DKW RT-125.
Just compare these pics:

The 2011 Yamaha Y125 Concept bike

The original 1955 Yamaha YA-1
The 1954 DKW RT-125

And the ORIGINAL 1939 DKW RT 125

For the record, the 1939 DKW RT 125 was a great design by Hermann Weber.

It appears that after WW2, the design of the DKW 125RT was open to anyone who wanted it. Some manufacturers aded it to their product portfolio, but other companies were started with that very bike as the first product.

From Wikipedia:
The RT 125' is a German two-stroke motorcycle made by DKW in Zschopau in the 1930s, IFA and MZ in the 1950s and early 1960s, and DKW in Ingolstadt in the 1950s and 1960s. "RT" stands for "Reichstyp" or "National Model".
In the 1930s DKW pioneered the Schnürle two-stroke loop scavenging process to dispense with the use of a deflector piston and improve efficiency of the combustion chamber. DKW also developed a highly efficient arrangement of transfer ports. These two features were included in the RT 125 to great commercial advantage. Competitor companies such as Adler and TWN copied the adoption of flat-topped pistons and strove to develop equally transfer port arrangements without infringing DKW's patent.
The RT 125 is probably the most copied motorcycle of all time. After World War II the Soviet Union took plans, tooling and even several dozen personnel as war reparations to MMZin Moscow (later transferred to MMVZ and SMZ) and to a factory in Kovrov, and produced copies of the RT125 as the M1A Moskva and K-125 respectively. WFM of Poland made a modified version of the RT125 (under SHL 125 and Sokół 125 brands), developed into 125/175 cc family motorcycles, produced until 1985. RT 125 plans were also taken to the United Kingdom where they became the basis of the BSA Bantam, and to the USA where they formed the basis of the Harley-Davidson "Hummer". Later Yamaha in Japan copied the RT 125 as the basis of the Yamaha YA-1.

Here is an array of shots some of these copies.

An American 1948 Harley Hummer

The English 1948 BSA Bantam

The Soviet 1946 Moskva M1A

An Italian 1950 MiVal 125T

A German 1941 NSU 125 ZDB

An Italian 1954 Maserati L/125/T2  (Italmoto). Its hard to see in this shot, but the Maserati engine is just like all the others. The frame is a bit more modern.

The first Italian Moto Morini, the 125 Turismo. Thile the top end is the same, the gearbox appears to have a different from the DKW.

The first Italian MV Agusta, the 98 Turismo. Looks like a DKW top end but again with a different gearbox.

An Italian 1948 Sterzi 125 Turismo

The first Japanese Kawasaki Motorcycle, 1955 Kawasaki (Meihatsu) 125

A Norwegian 1954 Tempo

The Czech 1949 Jawa 125

The Hungarian Csepel 125

There are lots more, google these up if you want to see more bikes closely related to the DKW RT 125.

Peugeot 55
Motoconfort 125
Triumph BDG125
James Comet 125
Sokół WSK M01, M06
SHL M02, M03, M04
Royal Enfield WD/RE Flying Flea 


  1. Hi Carl. Nice post. Bruno Cavani was the man to have introduced DKW to Italian markets, having been a DKW dealer since 1923. In fact, he was the first foreign dealer outside of Germany. After WW2 though, stringent import laws were killing his business - a ban on the import of bikes that weighed 185kg or less. Cavani had a plan. He imported just the motors, and then sourced the rest of the bike from suppliers in his his home town of Bologna. From after the war until 1957, Cavani produced DKW-powered 'made in Italy' 125, 175, 200 and 250cc motorcycles. I tested a Cavani-made 1955 RT 125 a couple of years back in Italy, and it was a gem. Full feature in the magazine soon...

    1. Ciao!
      Great history.
      Just for the record: an argentine called Ernesto Bessone bought the german DKW license to do the same thing like Cavani did back in Bologna, but this time in a hughe factory in Santa Fe, Argentina. From 1960 to 1965 there were a lot od "argentinian" DKW (originals, by the way) 125, 150 and 250 in the streets and some of them were introduced in near countries like Uruguay, Paraguay, etc. So Bessone did the same thing that Cavani. I own a DKW RT 125 from 1961 made in Argentina with the original german parts, some italians and the rest, from here.

      Cordiali saluti!

    2. Thank you this I had no idea there were so many copies this machine

  2. Hi Carl,
    above you show the NSU125ZDB as a "copy" of the RT125. This is not correct - the ZDB was an own construction from NSU. In example, the ZDB has a double port and no Schürle-system.

  3. Hello Carl, just a bit of added facts! you mentioned that the Triumph,TWN BDG125 was related to the RT125! well the only thing they had in common was there capacity ie 125cc. The TWN engine is a so called split,single ie 2 pistons,1 conrod,1 combustion chamber,1 plug.All Triumph,TWN motorcycles had this arrangement 125.250.350 cc after the war.Triumph,TWN along with the Austrian Puch concern were pioneers of the split single engine.regards Bernie

  4. It really does revolve around what you mean by "derivatives of the DKW RT125". Some of the bikes you mention bikes were direct copies of the RT125, some were inspired by the RT125, and some of the bikes you list have very little or nothing to do with it!
    My first question is always is the engine a copy of the RT125? Or does it just copy the barrel and piston design with Schnurle porting? So this is my take on your list

    H-D Hummer
    BSA Bantam
    Sokol developed into WFM and WSK

    Jawa (CZ)
    Tempo Which is fitted with a CZ engine. They also used Villiers and Sachs engines like many manufacturers


    Mi-Val. Not a copy as the bottom end is different (kick start and gear lever on different sides) Although the main website about Mi-Val (http://spazioinwind.libero.it/ghisla/mival) states
    "The first motorcycles produced (125 T) is an almost perfect copy of the DKW 125, both in the engine that the chassis" I think wiki is more accurate in stating
    "The philosophy of the MI-VAL was based from the start on the production of motorcycles cheap and robust, with a two-stroke engine , taking inspiration from the German DKW RT 125"

    Maserati As above
    "The company established a new department to design and produce their own bikes and their first model, the L/125/T2, was influenced greatly by the German DKW design"
    "The company established a new department to design and produce their own bikes and their first model, the L/125/T2, was influenced greatly by the German DKW design"

    Moto Morini As above
    " Launched in 1946 this first true Morini motorcycle was largely a copy of the pre-war German DKW RT 125. Unlike the Harley Davidson Hummer, Soviet Moska, or Britain's own BSA Bantam, the engine did not appear to be a direct copy

    Sterzi As above

    Kawasaki As above


    NSU ( as previous poster)
    Csepel The Csepel 125 engine is a bored out version of the 98cc engine designed by Aurel and Jeno Jurek in 1948
    Peugot 55 no obvious similarities
    Motoconfort. TBH I can't even find a 2-stroke bike, all seem to be side valve 4 strokes.
    Triumph BDG125 (as previous poster)
    James Comet 125 The postwar ML was a civilian version of a machine devloped for the Ministry of Suppy in WW11. It had a Villiers engine
    Royal Enfield WD/RE Flying Flea. "The Flying Flea resulted from a request by the former Dutch DKW importer for a replica of Holland's then best selling motorcycle, the 98cc DKW RT following the withdrawal of the DKW concession on religious grounds. Royal Enfield obliged, producing a machine that closely followed the DKW design, although they increased capacity to 125cc" (http://royalenfieldflyingflea.weebly.com)

  5. you all seem to have over looked the MZ RT125

  6. The Norweigian " Tempo " never had a DKW or kopi of a DKW engine as far i know , they used Sachs , Villiers and a 3 speed CZ engine.