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Discussion Starter · #1 · (Edited)
Hi Cafe Racer Friends,

as already indicated in my introduction I’d like to share a few impression of my little Kawasaki RSx with you. The base of it used to be called BJ250, or Estrella. An innocent and rather powerless bike, which didn’t sell very well here in Europe (most popular in Nippon though). No surprise, as everyone wanted to jump on the bigger Sister W650 in the 90’s.

Anyway, personally I have always been impressed of the nice and clean engine of this little Kawasaki as well as its relative simplicity. Likewise, I always thought, there must be something one can do about it to get it a bit more into the area of a classic cafe machine.

After all, the bike is now a 360 cc ‘beast’ instead of 250. Top speed is about 100 mph instead of 75, and weight about 135 kg instead of 146. And, most importantly, it looks like I wanted it to be:


Tire Fuel tank Plant Vehicle Wheel


Tire Wheel Vehicle Automotive lighting Motor vehicle


Home appliance Creative arts Household appliance accessory Machine tool Drilling



Hand tool Tool Wood Composite material Auto part


Motor vehicle Machine tool Gas Engineering Gear


Fixture Rim Bicycle part Font Nickel



Camera accessory Auto part Household hardware Technology Cameras & optics


Vehicle Motor vehicle Automotive tire Plant Automotive lighting


Tire Wheel Fuel tank Vehicle Automotive fuel system


Tire Fuel tank Wheel Automotive fuel system Vehicle


Kind regards

S.v.S.
 

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Wow!

You've got to give us some more information.
Details on whats been done to the motor?
 

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Discussion Starter · #5 · (Edited)
Hello,

I think the chassis is pretty robust and can probably cope with even more power. Also the mass production suspension is not that bad -just a little too soft at the back. Kawa uses 39 mm front fork on larger bikes - so the base is ok.

I procured better Ikon shocks and other fork springs, but this seems to have made things worse and harder to ride on bumpy roads.

Regards

S.v.S.
 

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Discussion Starter · #6 ·
As requested, this is the list of modifications to the engine:

  • removal of balancer shaft (2 kg @ engine speed)
  • self-made titanium con rod with 18 instead of 16 mm pin hole
  • lighter crank with ~60% balancing ratio
  • 360 cc instead of 250 by means of customized Wössner piston
  • customized 294 deg cam
  • head with modified inlet & exhaust port
  • 34 mm Dellorto PHF instead of Keihin CVK34
  • clutch with 7 instead of 5 disc pairs
  • secondary transmission ration 18/35 instead of 15/38.

Greetings

Siggi
 
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