The AJS “Porcupine” was designed exclusively for racing. It was a temperamental machine with finicky carbs and a penchant for killing magnetos, so it never reached its potential. But it was on its best days a fast and graceful motorcycle that gave England its first modern grand prix championship.
AJS built just four second-generation E95 Porcupines, making them less common than civility in politics. Bonhams will auction a 1954 AJS E95 later this summer, which is as good as a reason as any to run a few pics and tell you about this piece of motorcycle history.
The 500cc machines were conceived in the last days of World War II and designed to run supercharged engines. The engine featured horizontal cylinders for optimal cooling and a low center of gravity while leaving room for the blower above the four-speed gearbox.
AJS was neck-deep in development when the grand prix rulesmakers banned forced induction in 1946. Too much time and money had been invested in the aluminum dual overhead cam twin, so AJS revised the cylinder heads to increase the compression ratio, bolted on a pair of carbs and went racing.
Although AJS dubbed the bike the E90, everyone else took one look at the spiky cooling fins on the cylinder heads and called it the Porcupine. It did well at its first race despite a variety of problems, taking ninth and 14th place at the 1947 Isle of Man TT.
Development continued over the years and the Porcupine saw its greatest success in 1949 when Les Graham took first in the inaugural Grand Prix World Championship. It would prove to be the only title AJS and Graham ever won.
The bike was plagued by finicky carburetion and the magneto shafts were forever failing, sending AJS back to the drawing board. The new E95 featured cylinders canted 45 degrees to improve cooling and ease carb installation. It also got a host of internal mods and a revised frame. A pannier-style fuel tank lowered the center of gravity.
The E95 reportedly made 55 horsepower but never enjoyed the championship-winning success of its predecessor. AJS withdrew from grand prix racing at the end of 1954.
Bonham’s expects the bike to bring $750,000 when it is auctioned Aug. 18 at Quail Lodge during Pebble Beach Car Week.