The seller describes the motorcycle this way:
"When did you last see one of these then? Enfield in England produced a small number of these most desirable models right at the end of production. It differs from the standard Bullet in that it benefited by a completely new cylinder head with all the valve gear fully enclosed instead of the old leak prone bolt on valve cover. Hence the name BIG HEAD. Valves, pistons, and cam were all improved for performance."
Roy Bacon's book Royal Enfield, The Postwar Models, devotes barely half a paragraph to it, but the Big Head was certainly the most eye-catching change made in the Bullet motor in the final years of its production life in Great Britain. Bacon says that the Big Head had higher compression than previous Bullets, and that motorcycling magazines found it would do 91 miles per hour.
Progress of this sort for Royal Enfield in England meant nothing for the Bullet being built in India, which remained standardized on the Bullet as it had been in 1955. It is from those Indian made motorcycles that today's Royal Enfields descend.
Even in England, the Big Head was dropped in 1962 as Royal Enfield tidied up production variables. In 1963 the "New Bullet" emerged with the Crusader model's unit constructed motor.
Roger, the eBay seller, tells me that "I searched for four years before finding the Bullet in England. Imported it and enjoyed it as my main ride on summer club runs and rallies."
In his ad, he says: "I have a collection of Brit singles, this Enfield is by far the most remarkable. Tall gearing, complete lack of vibration, silky smooth transmission and four shoe front brake make it the bike of choice for club runs and outings with friends on modern bikes. The bike is completely original and unmolested."
The Big Head Motor. According to author Roy Bacon, "The 500 ... had its compression raised and was fitted with a new alloy cylinder head with cast-in rocker boxes to carry the valve gear, each sealed with a cover held by a single nut."
nice machine. i have a 1959 model. only 7 made, maybe some 1 maybe some 1 maybe like 2 bid at it, with a spare big head bullet engine
ReplyDeleteWere can i buy a 40 oversize hc piston for 1959 big head royal enfield apart from hitchcock as its not available
ReplyDeleteStay in touch with Hitchcocks as they have a huge pile of parts they have yet to index. Enthusiasts I contacted recommended these other possible sources. In alphabetical order they are:
DeleteBaxter Cycle
Burton Bike
Motoparts Inc.
Walridge Motors
Western Cycle Supply