Honda four-valve singles

Some big British singles were slow, basic but reliable plodders – such as Ariel’s Red Hunter or the Panther Sloper – but others, Gold Stars and Thruxtons among them, were some of the sportiest bikes ever made.

The very last BSA off the production line at Small Heath in 1973 was a big single, a 500cc B50MX scrambler for the US market, with its origins dating back to the 150cc Triumph Terrier. And with the B50 gone, it was felt by many that the big single had had its day.

The big single had not been forgotten, however. Three years later Yamaha came up with the XT500 and in 1978, the SR500 single. And Honda was also on the march and had been producing the four-stroke single engined XL250 and 350 trail bikes from 1972. The XL engine wasn’t just some basic big single either, it was the first motorcycle in large scale production (okay, so Rudge was first but not mass-production) with a four-valve head. The same concept has lasted ever since. You can buy a new motorcycle today with an engine that can trace its origins all the way back to that XL250 of the early 1970s.

XL250

The XL250 of 1972 was fitted with a four-valve head and was far more sophisticated than its British four stroke rivals, having a sohc wet sump engine. Fitted into a trail bike frame, the XL was soon the only mass-produced light-middleweight four-stroke trail bike on the block at the time. Faced with a range of two-stroke alternatives that were faster, lighter and more capable off-road and perfect for L-plates meant the XL wasn’t a big hit in the UK, where riders hunting for a small four-stroke preferred Honda’s