1973 Kawasaki F12MX
By early 1972, Kawasaki recognized a growing market in the United States for a race and
help develop the bikes.  Lackey rewarded Kawasaki at the end of the season with the
National Title.  By 1973, Kawasaki was prepared to release a limited production open
class motocross bike dubbed the F12MX.  They also released the 250cc version dubbed
the F11M.  The F12MX represented Kawasaki’s best effort to produce a competitive
motocross bike to the US market.  Unlike the F11M, which was based on the current F11
enduro, the F12MX was a ground up design as Kawasaki had no big bore bikes in it’s
current off road inventory.  The bike featured magnesium hubs, chromoly frame, custom
Kayaba shocks, plastic fuel tank and levers.  It weighted in at 212 pounds, 8 pounds
lighter than the F11M.

The projected number of bikes to be built was 200.   It is believed by many sources that
significantly less than 200 bikes  were ever released from Kawasaki.

This bike was confirmed as the test bike used in Dirt Rider Magazine in August 1973.  It is
also believed to have been the same bike used by Motocross Action Magazine, Modern
Cycle and Cycle World. It's history has been documented since it left the Kawasaki
Factory in Irvine.

In 1974, Kawasaki was prepared to release the production version of this bike.  It was
dubbed the Kawasaki KX450.  Kawasaki's dirt bike line has been referred to
"KX" ever
since.
The first "KX450" protype test bike in 1971
Photo compliments of Byron Farnsworth
This is a photo of this bike as it appeared in Dirt Rider Magazine in August 1973
Photo of the engine number as it appears in Dirt
Rider Magazine August 1973.  
F12E90245
Wyman Priddy moments before impact on a F12MX.
Photo taken by Tommy and Rita Gunter...... compliments of Greg Laves
Jim Cooke ex-Factory Kawasaki rider and one of a handful of riders responsible for R&D on the F12MX/KX450
Brad Lackey circa 1972 on a Kawasaki Factory F12MX
UNI levers came stock on this bike.
Greg Laves on his 1973 Kawasaki F12MX in
Beeville, Texas circa 1973
Looking for the original Lexan brake
pedal.  Top dollar paid!
Kawasaki Jersey signed by many of the riders and staff
responsible for R&D on the F12MX.  John DeSoto, Jim
Cooke, Brad Lackey and Bryon Farnsworth
Dirt Rider Magazine
Click below pages for actual article