Anatomy of a Knucklehead

Custom builder Ian Biddle talks us through the period details on one of his most recent creations


Words: Guy Bolton

Ian Biddle flies under the radar on the UK’s bike scene; not many people would guess at the number of exotic and downright cool old Harley-Davidson® bikes he owns and has built.

Although he has an enviable collection of ‘teen’ Harley® models, dating from before the 1920s, his real passion is Knuckleheads: the Motor Company’s technically-advanced overhead valve machine daringly introduced in 1936, when the United States was still reeling from the Great Depression. With a recirculating oil system and attractive art deco styling, the Knucklehead (so-nicknamed, as you’ll no doubt know, because the engine’s rocker covers look like the knuckles on a clenched fist) was marketed as a ‘sport’ bike and was an instant success.

This 1939 1000cc machine, which Ian built a few years ago, may look like it was just wheeled out of a mid-Western barn after a 70 year slumber, but it is in fact the result of a combination of collected parts, acquired parts and a little bit of wheeling and dealing.

Master of his craft

Ian has that rare attribute, ‘the eye’: he is extremely skilled at mixing parts from different sources to look as if they have been on the bike from day one. He has developed an enviable talent for mixing paint tones and finishes and gently aging parts to blend seamlessly with what is already there on the machine. Those amazing Atlas-style pipes, for example, are actually newly made by Jacksun’s in Japan and have been heavily breathed on by Ian to get that authentic ‘barn find’ look.

He explains how this lovely piece of work came together. “The ’39 motor came in a chopper I bought a long while ago”, recalls Ian. “I ran it in a couple of bikes before it ended up in a traditional chopper with high bars, springers and a little Bates seat.”

“I ended up selling that bike to my friend Tim and he turned it into a bobber. He searched out most of the cool parts you see on the bike: the Flanders bars and risers, the narrowed tanks, the smooth cam cover, the six-inch air cleaner, etc. I think he did a really good job on the bike – it’s very period, very gnarly, nice and dirty.” Look at any photos of bike events from the 1940s and you’ll spot motorcycles like this one: stripped down for competition on the weekend, with the fenders often replaced in time for the weekly commute to work.

Always authentic

“But as these things often go” continues Ian, “I got the bike back from Tim in a part swap for a Panhead and we both set about altering our respective acquisitions. The changes I made aren’t really that noticeable to most people... but so what!”

“I swapped out the later frame it had for a correct ‘39 and changed the offset forks to in-line, (’41 was as close as I could find). I found a 1939 transmission and kicker cover but the top is a ratchet to accommodate the hand shift.”

“Most of the other parts are even less obvious”, he laughs. “I mean, why do we bother? A correct round side stand, headlamp lens, shifter knob, battery cover, top clamp, headlamp mount…the list goes on.

Not just for looking at

His favourite part of the bike? “The Buco rear chain cover. You see these on workshop walls all over the place but you never see them on running bikes. They’re not that difficult to fit if you can find a good one. The awkward ones are the later Superior type. The Harley-Davidson ones and the early reproductions are best; the ones with the inspection hole at the bottom.”

“The bike runs great and it gets plenty of miles. I love that early skinny look with the 18-inch wheels and split tanks... it’s just a fun bike to ride.”

And despite the extraordinary money pre-war Knuckleheads are changing hands for now, fun is still what these great old bikes are all about.