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Torsten Hallman
July 12 2005 Lake Forest, Illinois

The center cases are based on the DT1, while the clutch cover is
sand-cast magnesium. The transmission uses hand cut gears
that are drilled for lightness and the clutch basket is machined
from billet aluminum. As on the Husqvarnas Torsten shifted
his bikes from the right side. The kick start lever is
forged titanium.

This is the
first reed valve cylinder. If you look close you can see
the weld buildup to house the reed cage. It was made from
a piston port works cylinder. The cylinder is chrome bore
and the porting layout is much different than anything Yamaha
offered at the time. Notice the hand fabricated brake
pedal that is actually mounted on the titanium swing-arm pivot.
All the motor mount bolts are machined titanium.

The spark is generated by a points ignition with a very small
inner rotor. The revs build up instantly. All the
coil windings are wound special just for this bike.

The air-box is a
custom one fabricated by Torsten. The stock one wasn't up
to the job. Torsten also took some packing foam that the
bikes came in and made a sock that went over the original filter
for extra protection. A man by the name of Mr. Bob Tuin
(pronounced twin) was
there that day and took Torsten's idea and started a company
called Twin-Air!

Looking at the rear of the bike gives one a sense of just how
trick and handmade this bike really is. It is the original
prototype YZ. The seat is not recovered, it is an
original new one from 1971. The seat pan is hand pound
from steel. Check out the special washers at the rear of the
seat. There were no silencers in those days. This
bike is real loud! Even the fenders are vacum-formed.


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