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From Green to Red |
This machine
is obsolete, not as in Team Obsolete but just plain obsolete. Current
motorcycle technology has moved far beyond this. Electronic ignition,
monoshock suspension, mag wheels, fuel injection, etc. was "not
there" when man made this bike. Ducati.
Most anyone who knows anything about motorcycles knows the name. But
how many of you know that Ducati made their first mark on motorcycling
history racing single cylinder four strokes back in the 50's? Their
first wins back then formed the basis of their success today. A design
they perfected then is still being used by them to win today. NOBODY
else does it. Desmodromics: comes from a Greek word meaning lots of
little shims that you don't have. No, just kidding. It means something
about perpetual motion and non resistance. Ducati's chief engineer,
Dr. Fabio Taglioni developed a valve system using positive control
of the up and down action of the valves without the use of springs.
A cam shaft was designed that had a lobe for the opening rocker arm
and a lobe for the closing rocker arm. More rpm's means more power. Valve spring technology limited how fast the springs could close those valves. Valve float is a term you don't want to know about and if you do, you know what to do: back off the throttle. Valve springs are stronger now but still limit rpm, not as much as they used to. Secondly, with the use of valve springs, the force needed to actuate them comes from engine power. If there is no spring resistance, no extra force is needed. Therefore more engine power plus another bonus of less wear on the valves, rockers, rocker bushings and cam lobes. You can actually turn the cam and actuate the valves with your fingers with a desmo.  This
is why in the late '50's, Ducati kicked ass against MV, Guzzi and
Mondial. The Ducati 125 cc desmo revved safely to 14,000 rpm, put
out 19 bhp and went 112 mph. In 1958, Ducati took the top 5 positions
at Monza, Italy in the lightweight 125 class. This 1969 350 Mark 3
Desmo street bike's engine design is based on that same 125 desmo
racer. It started life as a standard street production single cylinder
4 stroke 350 cc single. Mike Green is a vintage racer and builder of British and Italian race bikes. He helped start the California Vintage Racing Group and The American Historic Racing Motorcycle Assn. He built this bike for a friend who raced it for several years before selling it. In February of '94, Mike offered the bike to then senior editor Jon Thompson of Cycle World to race in the AHRMA event at the beginning of Bike Week in Daytona. Jon enjoyed racing this bike at Daytona but he had moderate success due to his large size: little bike, little people. If you find the June, 1994 article of Cycle World, you can read his story. Mike's bike was sold to a fellow from Indiana. I met him through the internet. He purchased some Duc stuff from me and later said the racing effort was down the tube and wished to sell the bike. I referred him to another fellow and they made a deal. The bike was sent to me to restore.  When I first looked at this thing I saw it was fairly beat. The fairing and tank were painted flat black and quite scruffy. The engine seemed to be in fair condition. The head had the same oversize racing cam in it as mine. The wimpy hairpin springs were removed and the valve retainer ears were trimmed back. I adjusted the valves after determining they and the guides were in good shape. The head was drilled for another spark plug. This allows faster flame travel across the top of the high compression piston. Faster flame travel makes fuel combustion quicker and less timing advance required. Getting full combustion sooner puts less stress on the crank and less heat build up. I found the piston and cylinder wall in good shape but the rings needed replacing. Next came a check of all bevel gear shimming. I found three transmission gears and one shift fork shot so I replaced them. All bearings were replaced. Then I put the engine back together.  Most race bikes use a total loss ignition system. That involves removing the stator plate and sometimes the flywheel. This action removes the engine's capability of producing electricity on its own. This is done because the magnetic force created by the stator's copper windings and the magnets in the flywheel take away some engine power. To get all you can out of the engine, you use a battery to supply the spark via the coil, condenser, points and plug(s). Modifications to the chassis included mostly the cutting off of unneeded bracketry from the stock street frame. Many lightening holes were drilled in gussetted areas to reduce overall weight. Passenger footpeg bosses were used for mounting custom rearset controls.  Suspension
mods in the rear consisted of a set of Works Performance shocks. They
are specifically designed for proper rebound and damping rates in
relation to the bike and rider weight. The front end is the "creme
de la creme" of vintage race bikes: a 35mm vintage Italian roadrace
Ceriani unit. This is the favorite and most sought after aftermarket
front suspension unit one can have on their vintage racer. They work
great and look beautiful. Wheel hubs are modified stock Ducati. The rear hub can be found on all Duc singles from '65 on. This one has been thoroughly drilled for lightness. Air flows in and out of the drum brake cavity keeping the pads and drum cooler. On the other side of the rear hub, the holding flange for the sprocket carrier plate has been reinforced. A light alloy sprocket carries a racing 428 chain. The front hub came stock on the last front drum Ducati single street bikes of the early seventies. It is an Italian Grimeca 180mm unit that has a single leading braking plate on both sides of the drum. By having braking power on both sides of your front wheel, you get an even resistance to your wheel on both sides when you brake. Stock rims on this street single were 18-inch steel rims that carried a 2.75-inch tire in the front and a 3-inch wide tire in the rear. This bike uses light, shoulderless alloy rims that carry a 90/90 tire in the front and a 100/90 tire in the rear. This increases tire width by about a third. Avon makes racing compound tires in small sizes for vintage racers. This is what I use on my racer and so does this one. So after purchasing a new fairing and rear seat, paint work, brackets and braces made and getting original WCBR decals from Mike, I was ready to put it all back together. Assembly went smoothly. The best time to test bikes in my urban historic neighborhood is in the daytime when most people are at work. In broad daylight you are riding a full blown vintage roadracer up a quiet suburban block, the sound penetrating further than any "home boy" and his woofers. I love it and you would too. I have only been dumped on a couple times publically about it and never been busted. I only do it when necessary. I know where this bike belongs but I also know that it has to be right when it gets there. So a little daytime disturbance goes with the "character" of the neighborhood!  Choke on? Got gas? Battery connected? No cars coming? I run and jump on it. The baby bellows on the first try. She takes throttle easily and quickly. Sounds great! As she warms up, I mess with the air/fuel screw and dial her in. How's the tranny working? Sticky. Tighten cable. Good! Now back to the street. All five gears? After a short and a long block, yeah! Ready to rock. Finally comes the fairing install. The setup was already done, I had to just put it on. The last thing to do was the fitting and mounting of the windshield. Both fairing and shield come undrilled. You drill and mount yourself. The fairing, tank and seat are replicas of actual body parts used by Ducati on early racing singles and twins (the seat). The body parts were not all used together at the same time. The colors and their design are Italian racing. I like the way the parts work together. The organic lines and the colors compliment one another. The thing looks fast just standing there.  So how does it work? These little bikes were known for their handling and sensitivity to the road. With the engine and chassis mods the bike will do about 110 mph now with about 35 hp at the rear wheel. The shift pattern is standard GP style: on the right with one up and four down. This is ideal for racing. When you up shift, you push down as though you are running forward. It works for me. The rear set foot controls coupled with the clippons bars put your body in a forward position that is shielded by the fairing. You feel like you are astride a missile that moves in the direction your body leans. Very little handle bar turning effort is required. Weight shifting does the work. As the engine rpm's rise to 5,000, the power comes on and keeps increasing till it levels off at 10,000. The exhaust note roars and spectators can hear you a half mile away. Engine vibration is noticeable but not nasty like a two stroke twin. The bars don't get fat in your hands and your feet don't buzz from the pegs. Braking is quite good and does not require blue knuckles. Now that this bike is ready to race, I hope that its owner will do more than turn it into static art in his office. The personal effort and knowledge put into this machine by Ducati, Mike Green and myself make this bike far from obsolete. It is very valuable in today's historic motorcycle racing venus. |
