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Remembering Sportster Knee

Harley-Davidson’s new Sportster S sure sounds terrific. It comes Bluetooth enabled and with a smart headlight called Daymaker. There’s suspension from Showa that adjusts to many different situations. The frame is there but is hard to see because it’s not “traditional.” The swingarm is a trellis-work item never before embedded in the Sportster line. The Max 1250T V-Twin engine crammed into the frame is liquid-cooled, with 121 horsepower and three power modes to choose from! Electronic devices control traction under all riding conditions.

It’s a marvel to think there was once a time when Harley-Davidson Sportsters didn’t even have push-button ignition. Generations of riders had to learn the hard way that the best way to bring those old XLCHs roaring to life DID NOT mean pouncing on the kickstarter like a wrestler bounding from the top rope to knee-smash his opponent lying helplessly on the mat. 

It’s easy to tell the Ironhead riders who insisted on strong-legging the kick pedal without proper form and technique—they’re the old boys seen hobbling around the local Swap Meets and Show ‘n’ Shines forever favouring their right side. They suffer from an affliction that still has its legacy victims (those of a “certain age”) but has now been otherwise eradicated from the general riding population. It’s called Sportster Knee, and yes it is a thing. Or at least, it was.

Already well-documented is how the Sportster is Harley-Davidson’s longest-running model, having been introduced in 1957 with the famous “XL” product code and iron cylinder heads. These XL Ironheads were served up in 883cc and 1000cc configurations with notoriously high compressions that would kick back if the rider failed to pay rigorous attention to the starting regimen—which involved equal measures of voodoo and science.

The Ironhead’s kickstart ratchet mechanism was to blame for countless torn ACLs, snapped femurs, and bruised egos. The source of the problem was when a worn bushing on the starter clutch caused the gears to slip out of mesh in the beginning of a kick. If the rider came down heavily on the lever the slip-through gears would offer no resistance and in that moment his leg was already hyper-extended. Hello Sportster Knee. Yet another victim.

The key was to put body weight into the kicking motion but without fully locking the knee at the bottom of the leg stroke. The alert rider would ensure the ratchet mechanism was fully engaged and allow for any “play” or wasted travel in the lever before bearing down. With the knee still partially bent on the down stroke, it was important to get off the kicker when the stroke was completely through to the bottom. ‘

Obviously, it also helped to have carbs and timing set properly. The Good Old Days, right?

by John Campbell Canadian Biker #355


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