Water-Cooled Knucklehead Chopper - Bacon’s Hog

With Harley launching its water-cooled bagger for 2014, a lot of us have freaked the hell out, maybe even stocking up on pitchforks and torches in anticipation of those bikes hitting showroom floors. Before you go all Frankenstein mob on your local dealership, there’s something you should know.Those baggers aren’t the first water-cooled Big Twins. No, I’m not talking about the V-Rod, either.

Back in 1937, midget race car tuner Dale Drake redesigned a Harley Knucklehead he could race in those little cars that had gotten so popular at the track back then. Drake had given up on the air-cooled two-cylinder opposed twin he was designing in favor of converting the Knuck to water-cooled cylinders instead. This was his answer to the Offenhauser four-cylinder motors that were dominating midget racing at the time. Compared to the Offy, Drake’s V-twin was 10 percent smaller, made more torque, weighed less, and gained better traction on the slick dirt and board tracks used for midget racing. This was all to the good on short runs, but put the Drake knuckle on a longer race and it ran into problems. They tended to overheat over time, losing power in the process. The cars shook so bad they were named “poppers.” Run one more than 4,000 rpm for a length of time, and parts started popping out all over the track.

By the 1950s some drag racers used the Drake Knuckles, but by that time Drake had sold off the parts and patterns. They passed through several owners, finally coming to rest with Edgar Elder in 1952, who had the original patterns until now.

Jesse James got the patterns from Elder. That’s where this chopper enters the picture. Dan Bacon Carr built it using a set of Drake barrels Jesse fabricated just for that purpose (while he was making some for himself, of course). Dan put his cylinders to good use between the rails of a long chop with a sick stance to it for Born Free 2012. Here’s what Dan had to say about building this sick puppy.

HB: Why a water-cooled Knuck? DC: Because I could, I guess. I was building a regular Knucklehead for Jesse James. He bought the patterns from Edgar Elder who had the original patterns for Drake cylinders. I did work on that project, kept asking Jesse for a set of cylinders.

HB: Tell us about building the motor. DC: Ron Weber got the cylinders ready to rock with sleeves and valve seats, machined for valve guides, etc. I built the bottom end with a set of Truett & Osborn flywheels with a 4-1/2-inch stroke and a set of ULH flathead rods and a 3-3/16-inch bore. I wanted to build a long bike after being inspired by the Highway Hauler bike on Negotiable Tim’s T-shirts. Ron helped me put sleeves in the cylinders and valve seats. I built the lower end and whole bike after that. The motor has long case bolts like an Evo.

HB: How did you make the Drake barrels fit into a chopper? DC: Those motors were made for midget race cars and cast iron. It was too porous, so aluminum worked out better. You have to do a lot of jacking around with the frame to make them fit. Jesse's got one in a bike, I do, and Ron Weber does, too. I had to jack up the seat post. Those cylinders are 2 inches taller than what you’d find in a regular motor. It was so weird the way it was; I thought it might look best in a long bike. My other water-cooled Knucklehead isn’t long but has a removable head. On this one, it's not.

HB: What’s the biggest difficulty you run into with this bike? DC: Having enough water in it. It’s overheated a couple of times. I have to run a bigger radiator. It’s like a regular Knucklehead with huge stroke and longer rods. The motor sounds different, too. I've ridden it a lot and had a few leaks. It’s wild to ride because the bike is so long.

HB: What would you do differently knowing what you know now? DC: I don’t know. I'm still kind of working on it. I’d probably run a different tank for more water capacity. Other than that, it’s pretty good. Maybe a two-up seat. I wouldn’t change too much to tell you the truth.

HB: How did you get into building bikes? DC: I started in high school back in Canada. I was on the verge of dropping out, but a teacher put me in a work program at a Harley dealership. I was there two months and bought a Panhead chopper. That was 16 years ago. We went through all the popular styles over the years. Before it was kind of rare to see a bike I actually liked in a magazine. Later I went to Harley school in Florida and dropped out and worked in shops all over the US, one in Charlotte for a while. Afterward I lived in California before Texas. Now I build a lot of motors and transmissions. People send me for jobs from all over the country. I get more old bikes than anything, but I have experience with Twin Cams and Evos but never get those. I get the old, broken, f—ked-up bikes [laughs].