| ►To the unsuspecting eye,
riding speedway motorcycle would appear to be easy. The bike is relatively
small, most speedway riders can touch both feet firmly to the ground at all
times. Its single cylinder motor, although at times deafly loud, doesn't appear
awesome as compared to say, a four cylinder TZ750 road race motor. And the
frail, almost genteel lines of the machine make it appear more as a bicycle than
a motorcycle.
But all that is to the unsuspecting eye. To the knowledgeable
enthusiast, one who understands the art and science of Speedway racing, there is
nothing but respect for the bike. Consider that most speedway race bikes, geared
for the short tracks in America measuring about 300-plus yards, will accelerate
from to 60 mph in about 3 seconds. And when they reach that speed, there are no
brakes. The bike must come to a halt by sliding it sideways, to scrub off speed
or plow head-on into the object in its path, as which case speed is scrubbed off
rather quickly.
The
fantastic acceleration is attributed to several factors. First, the machine
ready to race, weighs at or about 182 pounds. This helps keep the power to
weight ratio very low; as the 500cc engine generally can produce over 50
horsepower; a good running four-valve Jawa will produce upwards of 55-60. Taking
those figures, power to weight is roughly one horsepower for every three pounds.
A very impressive figure in any kind of racing. Of course final drive gear
ratios will vary with the number of teeth used for the given track, but it is
not uncommon for a bike to be fitted with a 3.75:1 ratio. Rear tire size varies
also, and may range from the common 19-inch tire that is standard in Europe, to
the new 22-inch that seems best suited to tracks with good traction, and is
popular in America.
As if this
isn't enough, speedway motorcycle engines burn methanol, and have compression
ratios well over 10:1. You can begin to understand that there is a lot more to
riding one of these bikes than just releasing the clutch, and setting her
sideways. You've got to know how much throttle to give it, and when and .how
much to lay it sideways. Tricky, indeed, but even more so when you have three
other guys diving into that first corner side-by-side. Over two hundred
screaming horsepower pushing and shoving to be first!
I had an
opportunity to saddle one of these bikes for a little test ride. The bike was
one of only a few Jawa four-valvers in the country. It belonged to Bruce Penhall,
and had been ridden by him only a few short weeks prior to second place at the
United States Nationals. He then upped the gearing, and took it to Ascot, where
he was just a nat's whisker shy of Kenny Roberts' track record set last October
on his Yamaha 750. I would be, quite frankly, riding one of the best bikes in
the country.
Jawa has
always been at the forefront of speedway design and technology. When the sport
was revived in America about ten years ago, most riders were on Jawas or JAPs.
As the sport evolved into a big money operation for many riders, technology
moved forward, and pretty soon there were more than just these two names
competing on the tracks of America and the world. This led Jawa to update their
old two-valve design to a four-valve conversion, and finally to this new motor
that sports two overhead cams and its own four-valve head.
 The
bike was one of only a few Jawa four-valvers in the country. It belonged to
Bruce Penhall, and had been ridden by him to second place at the U.S.
Nationals. I would be riding one of the best bikes in the country. 
Bore and
stroke measure 88mm x 81mm (3.464 in. x 3.189 in.) Talk about a thumper! Total
displacement is 492cc. Compression ratio is set at 13.5:1 at the factory.
Carburetion is via a single 38mm Amal.
Two
interesting features about speedway engines are 1) there is only one gear for
the engine, as it has direct drive from the clutch to the rear sprocket, and 2)
lubrication is through a total loss system. The clutch is a dry multi-plate,
type, and is located on the left side of the engine. The rider has only two
choices, pull the clutch lever in for neutral, or leave the clutch disengaged,
at which the engine will spin the rear tire. There is no second gear. Because of
this design, there is little power lost through a transmission, weight is kept
to a minimum, and the rider must be very selective as to when he lines up on the
line for the start of the race. If he stages too early, he has to either risk
overheating his clutch, or he sets the bike on the right foot peg/side stand,
allowing the rear tire to lift off the ground and spin freely. By doing this, he
saves the clutch, but also risks losing his concentration waiting for the other
riders to stage.
The total
loss lubrication system is just what is says. The oil is stored in a .5-liter
tank, and is pumped to the engine head via a mechanical pump. From here the oil
is drained to the lower end, where it spills out through
a small slit
on the underside of the engine. This sounds very messy and rudimentary by normal
design standards, but it is for a reason. First, it again helps keep the overall
weight and design of the engine light and simple. And since the racing lasts
only four laps, there is no real need to recycle the oil. Half a quart will go a
long way. This system also insures the top end of the motor, which is pitched
sideways half the time it is raced, a supply of clean, fresh oil. The tank is
located within the frame tubes. Jawa recommends Castrol R 40 weight, but
Penhall's bike uses Bel-Ray Four-Cycle Racing Oil.
The fuel
tank, a small metal container situated just atop the engine, holds two liters of
fuel, in our case, straight methanol. You can read more about this alcohol fuel
elsewhere in this issue. This is the accepted fuel for all FIM speedway racing,
and so was adopted by the AMA and Speedway Racing Association for use in
speedway racing in America. In the past, nitro was allowed, but no more.
The frame of
a speedway bike is quite unique. There is absolutely no suspension in the rear,
save the rider's butt, which is on the saddle maybe a fourth of the race. The
rest of the time he is busy standing on the right foot peg, and dragging his
left foot on the track for stability.
The front
forks are a little closer to normal motorcycle design. Travel consists of about
50 millimeters. That works out to about 21/2 inches of travel. Not much, and the
rider hardly feels it. Steering angle varies with each rider, as some reduce it
even more than what is supplied from the factory. The style needed for speedway
racing, the steering angle is typically very little so the bike can be pitched
into a slide with little difficulty. Steering, then, is very quick.
The
particular bike I was to ride had a slightly altered frame, to suit Penhall's
riding style. The front tire would be the normal 23-inch diameter type. The rear
was a 22-incher. The 22-inch tire replaces the standard 19-inch as comes from
Jawa. Most riders favor the 22-inch for better traction. As the track surface
may deteriorate, and become slick, a 19 is put back on, with a universal tread
tire that has been cut according to the wishes of the rider, much like Class C
half-mile riders do.
Bruce would
not be able to make this little test session/speedway debut by me, as he had
other commitments. His tuner Chris Haines would assist me. Haines has ridden
speedway too, but this past year parked his bike to help Penhall. Their year was
very profitable, as witnessed by their fine showings throughout the year,
including qualifying to represent the United States at the Inter-Continental
Round for the World Finals, and second at the U.S. Nationals last October.
Haines kept the bikes in perfect running order all year, and both bikes were
spotless at each race. Today would be no exception. My bike was clean and ready.
All we had to do was take it to the test track, and fire her up.
The track is
owned by Penhall and Dennis Sigalos. Since the race season had just finished,
the track wasn't in the best of condition. Haines and I groomed it, then watered
it down, taking about one and a half hours to do. This is absolutely necessary,
as poor track conditions will make riding almost impossible. As it was, the
first turn had several ruts, making an outside line mandatory. The second turn
(or turn three and four) had a bad entry, but an excellent exit. This proved to
be a good thing for the test, as I would have a chance to experience several
conditions at one time.
Chris
checked me out on the bike, showing me the kill button on the left handlebar,
and informed me on how to use the clutch. Then he gave me a brief lesson on how
to enter, slide through, then exit a corner. I would be on my own from there on.
Starting the
engine requires a second person to push start. There is no kick or electric
starter on this bike. Chris pushed me, and I let the clutch out, without pulling
the throttle. As the motor came to life, I then gave it a little fuel and once
it got going, let it motor around the track for warm-up, gingerly touching the
throttle so as not to load the plug. I must admit, I had apprehensions as to how
powerful the engine would be even on fire up. I could only imagine myself giving
it too much fuel, and taking off, front wheel in the air, Chris laughing and
cringing as I fought to get things right. It didn't happen that way, thank you.
The first
couple of laps were taken pretty easy. I wanted to get the feel of the bike, how
much throttle to give it, and try and accustom myself to having no brakes.
Shakey proposition, I told myself, but what the heck. That wall wasn't too
sturdy, after all Chris and Bruce were the ones that put it up!
You will
also note that I am wearing an old pair of black leathers. These were the ones I
learned how to road race on, and so decided I would become a speedway star using
the same pair. (Actually, I had a road race coming up the following weekend, and
didn't want to destroy my nice brown and white ones. Pessimism grew deep with in
me… I didn't tell Chris, however.
It felt
awkward at first. My right fool was firmly planted on the right fool peg/side
stand, but my left foot, steel shoe and all, seemed lost. The left peg on the
bike is about as useful as a Cricket lighter in a four alarm fire It is small,
and tucked out of the way in the event the rider tosses the bike way over —
which happens. But not today. I finally made it easy on myself and just rode
with the left foot dragging on the ground. After all I didn't have to shift any
gears, right?
After three
laps, I mustered up some courage to wick the throttle some more. This would be
done exiting the corner, where the crash wall ends. I tried to make myself feel
like Bruce Penhal I, left foot pointed outward, most of the weight on the
outside heel and little toe. My right leg was straightened out, trying to remove
as much weight from the peg (and subsequently the rear wheel) as possible.
Elbows out, throttle hand positioned so I could roll the grip back towards me
without disturbing my stance, then one, and two, and one, and two. Like a
ballerina. And the grace and beauty of a court gesture I wicked the throttle,
and to my amazement the rear tire began to come around. I let off too soon (a
good rider never lets off the throttle, or he loses races) and the bike felt as
if it would high side. That right there told me a lot about how to ride the
bike. It is much like a road racer with slicks. The harder you ride it, the
easier it is.
I came in
after that lap, gasping for breath. Not because it scared the beegeezuz out of
me, but because it required so much from me physically.
Bore
and stroke measure 88mm x 81mm (3.464 hi. x 3.189 in.) Talk about a thumper:
Total displacement is 492cc. Compression ratio is set at 13.5:1 at the
factory.
Chris
mentioned that I would be using muscles I had never used before, and he was
right. I try and keep myself in pretty good shape but after four laps, I was
tired and sweating profusely from head to toe. On top of that, the sun had come
out, and we were just entering a Santa Ana conditions, where the desert winds
blow in, bringing with them unwanted heat.
Chris
checked the oil and fuel, gave the bike a quick once over, then told me what I
was doing wrong. I like those positive attitudes, makes me feel like I was at
least doing something. Better put than "what I wasn't doing right." We fired her
up, and I went out for some more laps.► |
Competition 
