Top 100 motorcycles of the 20th Century
The 1924 Moto Guzzi 500 Four Valve Racer
by Murray Barnard


Moto Guzzi, the name immediately conjures up visions of push-rod, two valve, shaft-driven V-twin machines which pump out far more power than their design should allow. Picture the factory 65 years ago; 1923 to be exact, are the engineers conjuring up dreams of pushrod power? Far from it, the factory is hand building over-head cam, four valve singles. The 1924 Mote Guzzi racing motorcycle ieatured in this article is an O.H.C. 500cc single cylinder, horizontal four-stroke with very advanced technical features for it's day. The engine generated around 22 BHP at 5,500 RPM which propelled it at up to 100 MPH. The Guzzi story began only a few years before the construction of this four-valve racer so it's advanced specifications are even more remarkable.


The Moto Guzzi factory was founded in 1921 by Giorgio Parodi and Carlo Guzzi. The famous winged eagle badge was derived from Parodi's wartime aviator's badge. The company was established on the shores of Lake Mandello where it remains to this day. The first motorcycles off the production line were remarkable machines for their time. The initial design was a horizontal 500cc single cylinder fourstroke, a design they stuck to until the early seventies. The head and barrel faced forwards thus ensuring good cooling for the motor and was arranged in front of a three-speed gearbox which ensured all the heavy components of the bike were as low as possible. It was an over-square motor (88mm x 82mm) which produced 13 b.h.p. and reached a speed of 80 MPH with ease.


The first Moto Guzzi Grand Prix machine was based on this design and it's solid construction, good handling and performance allowed the bike to carry off the 500cc class in the 1921 Targa Florio in Sicily. The widely splayed twin front down-tubes were braced just above the motor and the steering head was rigidly supported giving the bike a strong frame for its time. The bacon slicer design with the exposed flywheel on the left hand side of the crankshaft was purposefully designed to keep the engine's main bearings close together. The engine soon proved to be as solid and reliable as the rest of the machine.


The Moto Guzzi firm decided to create something really new and the company's racing department prepared a new 500cc engine with a four-valve overhead camshaft head.


Riding the 1924 Moto Guzzi 500 racer is a singular pleasure, especially with a motorcycle as rare as this one. The four-valve racer featured is one of two apparently imported into Australia in 1925. Boro and Franki, Fiat agents in Newcastle, imported both machines. Although its early life is sketchy; around Maroubra Speedway in 1926 it reputedly attained 100mph. It passed through a few hands and was discovered in Northern NSW. For many years it was on exhibition at Bronk's Museum at Watson's Bay, Sydney. Upon closure of the museum the bike was offered for sale.


The motor started easily and ran with a solid beat despite a cloud of smoke from it's recent idleness. The controls are easy to use and the seating position is natural even with the rearward setting of the footpegs. The clutch was effective and take up was smooth and progressive. The engine impressed with its strong thumping power, proving very tractable and able to propel the bike at a respectable rate. The low centre of gravity was immediately noticeable allowing for stable steering and control despite the spartan suspension. Unfortunately the ride impression did not allow for a test of the machine's high speed abilities but the lasting memory of the ride will always be that beautiful motor. A very special Moto Guzzi indeed.


The last that I heard from Steve Hazelton he still had this wonderful machine.

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