The motor is
very compact with tiny sand cast magnesium crankcases. It
does not hold much gearbox oil at all. It has carbon fiber
motor mounts in the front and an aluminum cradle in the rear.
The swingarm actually passes through the rear engine cradle.
The motor mount bolts are titanium and the outer case screws are
aluminum. The porting arrangement favors mid range power
as the transfer ports are huge. (see cylinder in "works parts")
The reed cage is very large and is fed from a 38mm mikuni
(stamped OW40) made just for this bike. Different pipes for
different powerbands were available. The kickstarter is
A very small
ignition (stamped OW40) uses a map curve just for this bike, and
has a very small rotor. The revs build up instantly.
This is all connected to a very small black box that is mounted
in a fabricated aluminum bracket just ahead of the ignition
coil. Notice how close the countershaft sprocket is to the
chain buffer. Also notice the access hole in the frame to
get at the upper motor mount bolt.
The rear hub is a
very small sand cast magnesium unit that looks like it belongs
on a 125. It is laced to a Sun rim with Buchanan stainless
heavy gauge spokes. Bob preferred this over the larger
ones used by the rest of the team. The chain adjusters are
machined from aluminum with brown anodized inserts that hold the
chain adjusters in place when the axle is removed. The
ring that you see bolted to the hub is made from stamped steel.
It's purpose is to keep a derailed chain from getting tangled.
Very Clever. In the lower photo, notice the custom wing
nut extended far enough back for easy brake adjustments.
The rear torque arm is made of chrome moly and attached at both
ends with heim joints for smooth performance. The entire
rear wheel assembly is very light.
Anyone that had a
Yamaha YZ in the late 1970's wanted a swingarm like this.
The shock mount was much lower than stock. And the long
sleek looks really stood out. It is a work of art.
Check out the welds in the lower photo. There were several
lengths that the riders had a choice from. This was the
longest and Bob used this for the whole season. The bike
tracked very well with this set up.