Funky five hundred

A 40-year-old high-tech twin enjoys a new wave lease of life.

- Joe Mcdonald

THIS IS TONY’s Yamaha XS500. We all know the XS650 makes a great flat-tracker. They were even fitted with big-bore kits and raced quite successfully in the States. But Tony was on a tight budget (and we also all know how that feels) and didn’t have the funds to throw at one of the bigger Yams.

Undeterred, he scored this 1977 XS500 off eBay for a mere £250 and went from there. And 10 months later, not having spent a fortune, this is what he ended up with.

In actual fact, the XS500 was a great choice in the end. It’s quite a cool looking motor in its own right. With its dohc top end, rather than the 650’s single cam, it’s only actually 1.5bhp less powerful than the bigger twin. The 180° XS engine was rather more complicated than the original 650 or your average British parallel twin: eight valves were considered pretty exotic in 1976. It also incorporated a counter rotating balance shaft and counterweights to subdue vibration, two trochoidal oil pumps to ensure good lubrication and an electric starter for instant action.

All this and more engineering complexity were needed to help Yamaha’s middleweight twin compete with Honda’s middleweight fours. It didn’t quite succeed; from new the XS500 tended to run rough at low revs and feel flat in the midrange. It only really got into its stride above 6000rpm, and suffered from considerable lash and lag thanks to all the gears and cogs in the drivetrain.