Offered from The Forshaw Speedway Collection, PJ GM Laydown Speedway Racing Motorcycle

Frame no. 1504 PJ LD Engine no. 8590

• Historically the culmination of The Forshaw Collection and the only 'laydown' in the collection
• Rare example of a highly sort after machine

This Peter Jarvis 'laydown' machine is historically the culmination of The Forshaw Collection. An illustration of the laydown future and an introduction to the world of speedway today. It could be argued that the Douglas machine of 1928 was the first laydown with it flat twin engine nearly 50 years ahead of the laydown future. This initial if short lived overwhelming success of the Douglas was the proof of the concept. Unfortunately as a fore and aft flat twin engine the wheelbase was much too long also resulting in unnecessary extra weight. Other early attempts at a flat or laydown arrangement were notably made by McEvoy, the first to produce a flat single for the dirt track and very much later by George Wallis who inclined a JAP engine in 1948.

The concept of horizontal engines in racing are well known particularly the very successful Moto Guzzis. Even Norton flirted with the idea in the 1950s but discarded it before it ever reached the track reverting to the trusted but out-dated Manx models. With hesitancy to use laydown engines in speedway it was not until 1974 that Barry Biggs and Martin Ashby appeared at the Brandon Stadium with a strange device, the well-known Jawa engine sitting nearly flat in the frame.

So far as handling was concerned it was a revelation but with the engine designed to be vertical but now horizontal there were problems to be solved. Engine balance had to be drastically revised and the carburation was terrible. The vibration was so appalling that Ashby reported on that inaugural test that the handlebars, "felt about a foot in diameter".

The concept of mounting the engine as low as possible to spread the mass led to vastly more grip and acceleration as well as being faster through the bends. However, the apparent potential phenomenon took a long time to be understood before the problems could be solved. It was another 10 years in 1986 before Barry Briggs continued to persevere with the problem although others had tried it out as well. Briggs discussed it with the renowned Alf Hagon who immediately appreciated the concept and started experiments himself. As Martin Hagon, Alf's son, has said the two problems were engine balance and carburation. The former was soon solved, and carburation was improved with a Wal Phillips fuel injector. Not an injector at all but more of a straight tube with no need for a float chamber - fine with methanol and with no concern for fuel economy.

It was in Long Track racing where the problems with the laydown engine were finally laid to rest and eventually this filtered through to speedway. There was a lot of resistance to the engine particularly in British speedway where the engines were actually banned in 1995. But with Hans Nielson winning his fourth world title that year with a laydown Jawa the immense pressure for change became an unbearable force, an incoming tide that was not to be stopped. Laydown engines flooded British speedway. Jawa had mastered the problems overwhelming GM for a time but eventually GM took control and from 2007 they have dominated the sport with Jawa and others struggling to make an appearance.

This Peter Jarvis machine with its GM engine is both a reminder and a document of the new world. Peter Jarvis had been a notable cycle frame maker before he made his first speedway frames from 1977. His earlier experience with ultra-lightweight frame making stood him in good stead. Jarvis speedway frames are highly sort after, and this PJ is a very rare example. The mechanical condition is not known and therefore we recommend re-commissioning and/or restoration to a greater or lesser extent.
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