How to build your "JPN" (part I)

Last month we have talked about the "Pliquet" bros. and their adventures to the "Bol d'or classic", today, let's talk about another of their realization, a first part of two beginning with a frame building.

Since the last few years, I make demonstrations with my Gus Kühn :(Ton Up, Gérard Jumeaux, Coyote Racing team, etc.).. The bike is just modified with a 4s camshaft. 
I wanted another motorcycle more Racing and keep the Gus Kühn for the road. 
In March 2002, a friend suggested to me a basket case he has accumulated for more than 15 years, as a project to make a racing bike. 
This batch consisted of an stock frame, Marzocchi forks, a Norvil tank, a prepared cylinder head with big valves,a 36 mm carb, a high compression piston ,a standard gearbox, a MK III
isolastic, a Norvil brake, a JPN saddle, one Carrillo rod, 
a lightened crankshaft and an aluminium alloy primary belt kit. 

On November 1st the same year, 
I started the bike. Immediately,,I had a big problem 
with modified cylinder head and large carbs. The engine was no longer fit into the frame.So I had to find another one. 
I decided to make it myself.

I wanted an original motorcycle and I choose to make a John Player model 1974 frame. I found inspiration in JPN and Ducati pictures and I made so many drawings to imagine the shape of frame.

Then I started cleaning up and up fork, a Marzocchi 
which should be mounted at the time on a Ducati or Larverda. 
Later I bought two front wheels in a scrapyard. 

I machined the hub to give it an English look. I mounted new spokes and a new rim a wheel axle and set two disk brakes of ZXR ... with Grimeca calipers making plates in aluminium.

In December, with a clearer idea of the frame's shape and how to achieve it, I began by making a marble with a metal beam ,
to install the original frame as well as the emptied engine. From there I identified the attachments points of the 
steering column, the shock absorbers and fasteners engine ...

I removed the frame from marble but I kept the engine with the isolastic support and I have corrected the angle of 
Flush of 1°to reduce the bike of 40 mm. 
Then I made the isolastics aluminium alloy support and one swingarm with 30 x 40mm tube ,machined sockets, I used to 
fasteners on the frame. Finally there I just had to connect 
the attachment points with tubes and welded with TIG. Once the frame fully welded, I have withdrawn from marble and have assembled the fork and the swingarm first with Fournales 
shocks absorbers that will be replaced later by Koni. I turned a rear wheel axle and milled aluminum plates for the footrests. 

Next week: Ready for the Track?      "GO"