Hello Everybody, I've had these picture up for a couple weeks now, so
I guess I'd better add some text to let you know what you are looking at,
highlight the points of interest so to speak.
This is me with the finished product. The bike is 1974 Rokon
MX 340 C, the "C" stands for Cobra. I'm told that there were between
60 and 70 of these bikes made, mine is Number 31, it has a cool plate with
the "31" rivet to the frame, you can see it in the picture below, it's
just in front of the gas tank. I have a close up of it that I post
later.
The engine on this bike is not the Cobra engine, it is off of a RT
340. I thought it would be a good idea to start out my return to
Motocross racing, after a 25 year plus absents, with milder tuned engine
than the orginial Cobra engine. I took this option as a matter of
self preservation. If I get really into racing, I'll rebuild the
Cobra engine later.
The other major non-stock component is the swing arm, this is also
off of an RT 340. I choose this option to comply with the AHRMA rule
that states the rear suspension travel cannot exceed 4", even it the orginal
model came with longer travel suspension. The Cobra swing arm has
vertically mounted shocks that attach about midway between the rear axle
and the swing arm pivot. I picked up a pair of Koni shocks that had
the same part number as the orginal shocks, but over the years the spec's
have changed. The bodies are now chrome, the orginal were black.
Due to change is the top eye assembly the springs a different, larger diameter,
so I had to get new springs too.
The seat was ripped so I had that recovered locally. I redid
the the brake lines with stainless steel braided hose and cover them with
clear tubing, not exactly period, although available at the time, but they
work a lot better. I also got a pair of K&N bars and one of those
90 deg. twist grips at swap meet. Other than that I think the rest
is stock Cobra parts. Oh yeah, I almost forgot the creative plumbing
on the rear caliper is due to the new shock location on the swing arm.
I was hopeing to take the bike to the AHRMA Regional MX in Indy on
June 26, but it doesn't look like things are going to work. The bike
first outting will probably be Mid-Ohio Vintage Motorcycle Days.
I had a great time putting the bike together, maybe I'll find another project
at Mid-Ohio.