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Bike Tale - Posted 15th June 2015
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Bill Kitchen Speedway JAP

At the end of 2014, Odgie wrote about a magnificent speedway machine in the pages of the monthly RealClassic magazine. Ray Smith was inspired to do some background research on the subject...

The ex-Bill Kitchen speedway JAP which appeared in RC128 is a wonderful original, and the owner intends keeping it that way. Itís a pity there arenít more Real Motorcyclists with the same set of preservation values. Itís a wonderful piece of history and the owner is on the right track not wanting to turn it into an ornament, as unfortunately has happened to so many good, sound running motorcycles showing their history in their appearance. Wish it were mineÖ

Bill Kitchen Speedway JAP

Initial investigations suggest that the engine is not from 1928. The engine codes 1920 to 1939 were recycled for the years 1940 to 1959. The dating code C applies to both 1928 and 1948. The engine is a five-stud speedway JAP, manufactured from 1935 to 1949 inclusive. This one would appear by the date code to have left the factory in 1948. Itís fitted with the head casting introduced after WW2 to suit the five-stud and the later four-stud engines. A four-stud casting boss can be clearly seen in the drive side photos ahead of the spark plug and outside the first cooling fin.

Itís also fitted with the big fin alloy barrel, used for better cooling in rear engine racing cars. This barrel wouldnít normally be used in a motorcycle, unless itís being run on petrol, but there appears not to be a compression plate, normally a requirement in those circumstances.

Five-bar frames first appeared in about 1935, and were in common use until 1947. There is a photo in Cyril Mayís book, of Bill Kitchen racing in 1941 on an old early 1930s three-bar frame, prompting the assumption that he may not at that time have had access to the later frame.

The origin of the frame isnít obvious, and Iím no expert. However given that tube welding techniques were perfected in aircraft manufacture during WW2, and given the remarks in the previous paragraph, could this frame perhaps have been manufactured in about 1946? A strange feature of the frame is that the upper rear stay, normally a bolt on component, seems to be a fixed part of the main frame.

Bill Kitchen Speedway JAP
Speedway Stuff on Now...

The impression is that this is a machine ridden well past its use by date, with minor changes made to suit the rider, alloy engine plates, front guard, and elaborate rear sprocket. The handlebars are much later than the rest of the bike. The footrest is in a strange position; it should be hanging vertically down. The fuel lines and filter are unsightly. And thereís a bodged-looking push bar. And thereís one other thing wrong with this motorcycle Ė itís not in my shed!

Further study on this subject has uncovered a few facts and some assumptions.

Jeff Clew details the engine code system for 1920 to 1939, with the same sequence used in 1940 to 1959 (ref 1 p236/237). I have a JAP 4A with the date code U. These engines were made from 1948 to 1966 so it fits neither of the previous code sets. I think the codes were re-used for a third time, making it a 1963 engine. The 84S engines made in 1970s use a different coding system.

As previously noted, the five-stud JAP was made only during the years 1935 to 1949. The Bill Kitchen engine is not 1928, however the same code was used for 1948. A 1928 model (and the early speedway engines) would have Ďdog earí rocker mounts and exposed pushrods rockers and valves. The head would have had twin exhaust ports, and the inlet port would have been horizontal on the left side. There would have been a single Pilgrim oil pump. Strengthening ribs on the crankcase were single ribs vertical and horizontal. The JAP logo on the timing cover was horizontal small block text. Changes to this specification occurred as follows:

  • 1931 The script JAP logo appeared
              ref 1 p88, see below
  • 1932 Horizontal crankcase ribs
  • 1932 Alloy rocker box and enclosed pushrods
  • 1932 Single exhaust port
              all ref 1 p92/93, see below
  • 1933 Right side downdraft inlet port
  • 1933 Valve guide oil feed
  • 1933 Double Pilgrim pump
  • 1933 Longer conrod and barrel Ďlong fourí engine
              all ref 1 p95, see below
  • 1934 Splined drive sprocket
  • 1934/1936 development of enclosed valve caps
  • 1935 Five-stud engine
              all ref 1 p96, see below

    After WW2 the head was re-cast to eliminate the need for the five-stud engine. Also at that time large fin alloy barrels became available for use in rear engine race cars. There was a two year overlap between five and four stud engines (ref 1 p98).

    During the aforementioned two year overlap, the head casting could be machined to suit either engine type, and Iíve seen heads with all seven stud positions fully machined to enable bolting to either type. In the drive side photo on page 52 of RC128, the same arrangement can be seen in the crankcase casting, with four stud bosses prominent, adjacent to the engine plates. Examination of a 1953 4A engine I have, shows that the protruding boss for the central fifth stud has been machined off, which appears to have been done at the factory prior to despatch.

    The Bill Kitchen JAP has well base rims. Beaded edge rims were used by all speedway riders until 1933, and many were using front beaded edge tyres into the late 1930s (ref 1, 2, 4 photos).

    Clutches became mandatory on speedway from 1932 (ref 1 p93). The speedway Rudge probably used a clutch prior to that date. The Kitchen JAP and most other speedway bikes through to mid-1950s used the same Rudge clutch and countershaft.

    The article mentions Martin frames and Martin Rudge. Victor Martin was a JAP employee. Early frames he built and sold were direct copies of the speedway Rudge, by arrangement with Rudge. They were fitted with JAP engines and sold as Martin JAPs (ref 1 p93). Itís possible that Martin also supplied Rudge with some of his Rudge pattern frames.

    Martin also made frames on the Wallis pattern with JAP engines. The ĎMartin Rudgeí mentioned in RC128 is likely to be a Wallis pattern frame with a Rudge engine. My understanding is that this would not, as a complete motorcycle, have been built by Victor Martin, and is probably a machine put together by a rider for his own use and using his choice of the best available components, a not uncommon occurrence in speedway, then or now.

    The other use of the ĎMartin Rudgeí term is the clutches and countershafts used almost universally well after the original manufacturer had ceased production, but which continued to be supplied by Victor Martin, who also supplied the Alfin barrels, branded as such, and fitted to JAP 4A and 4B engines

    The BTH magneto with manual retard and the 7/8Ē bars are later additions. The six pin rear sprocket is a mystery to me but obviously original pattern as the double sided hub has mounting pins both sides.

    Bill Kitchen Speedway JAP

    All pretty straightforward stuff. Now to the really interesting bit: The Frame.

    There is a photo of Bill Kitchen in 1941 on an old frame of early 1930s design (ref 2 p56). Itís inconceivable to me that heíd be riding such a bike if he had access to the machine featured in RC128.

    The five-bar frames were only made between about 1935 and 1947. My previous remarks about the perfecting of tube welding techniques during WW2 leads me to the assumption that this one was made in the latter year.

    Many old speedway frames can be identified by the configuration of the rear axle plate and struts. A recent publication (ref 3 p27), shows twelve different frame rear ends. The RC128 bike matches none of them, not surprising given the number of track bike frame designs extant, several hundred, maybe more.

    If the engine date code is C, then itís indisputably a 1948 model. Bearing in mind that the UK manufacturing year was 09/47 to 08/48, this engine could have been made in late 1947. Alloy engine plates, the big fin barrel, well based rims, and the shape of the exhaust, indicate post WW2.

    The fabrication is exceptional; the cutaways and drilling noted by Odgie and the variable tube sizes seen on the front downtube and seat tube (RC128 p52). ĎBill Kitchen ... is on record as having built his own frame ... in 1947, called the Utensilí as Odgie explained.

    Could this motorcycle be the Utensil?

    Photos by Odgie himself

    References
    1 JAP The End of an Era, Jeff Clew 1988, ISBN 0 85429 611 5
    2 Ride It The Complete Book of Speedway, Cyril May 1978, ISBN 0 85429 210 1
    3 Speedway Workshop vol 2 no 7, Tony Webb 2014 (info from Noel Clark)
    4 A History of Australian Speedway, Jim Shepherd 2003


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