How to build a Harley

Jul 09, 2023

Visordown caught up with Kyle Wyman's chief Mechanic for the King of the Baggers championship to find out what it takes to make a Harley-Davidson a winner

SINCE the first YouTube clips were discovered by us Brits’, the King of the Baggers (KotB) championship in the US has been winning over a lot of fans on this side of the pond. It features a field of Harley-Davidson and Indian racers, as they battle at some of the best tracks in the USA.

Featuring large grids of extremely trick American cruisers, pro riders, and a hugely competitive talent pool, the KotB events prove to be highly entertaining and genuinely jaw-dropping spectacles. But while the machines may look like carbon copies of the bikes you or I can walk into a dealership and buy, there is a massive amount of work, and a large amount of cash put into making them the fearsome machines they are.

At Motorcycle Live we caught up with Dave Hopkinson, the chief mechanic for series front-runner Kyle Wyman and his Harley-Davidson Road Glide. He's responsible for the bike at every round of the championship and is already working on the 2023 machine.

The 2022 bike, nicknamed ‘Big Blue’, was the second machine Harley built for the KotB championship. But as Dave advises, the route to getting to the front of the grid has not been easy, or cheap. "It's extremely important to Harley I mean, they sell 100,000 bikes a year.’ He said. ‘So, it's vital to get out there and be involved with the racing, to not only reach the people that already love Harley but people like myself that are new to the [cruiser] segment."

It doesn't come across in this written interview, but Dave is, surprisingly, not American, in fact, he cut his teeth in top-level racing on this side of the pond, including the Isle of Man TT and British Superbikes. "I was Leon Haslam's chief mechanic in BSB. I've done World Superbike, again with Leon. And I've done 18 years at the Isle of Man TT and the roads. So, I've been around… When they placed this thing in front of me and asked me to make a race bike, I thought ‘What on earth are we doing?’ Honestly, my initial thought was ‘they're off the heads’. But the more and more you get into it, the more you realise it's as pure as racing gets. You start with something that's not meant to race and you turn it into something that can lap fast enough to qualify at the back of a superbike grid."

Built at a cost of $500,000 you would be forgiven for assuming this is just some silhouette racing machine, a pastiche of a road bike, with a race bike underneath. That isn't the case though, and as Dave advises, there are some parts on this bike that haven't changed at all since the 1930s. "She's 283 kilos or 625lbs, it's right on the limit and is powered by a 2.1-litre engine. It's got the power of a race-ready superbike, and around double the torque – don't ask me for specifics, if I told you I’d have to kill you... the whole bike has to tolerate the kind of torque this engine puts out which is, like I said, around double what a normal superbike would produce."

"Another problem you have to solve, that is pretty unique to Harley. If you look at the chassis, you've got a standard frame and the engine sits on rubber mounts. Then there's the swingarm which attaches to the engine, not the frame. So it's not a true connection between the swingarm and the frame. To fix that we have it set up really strong, with minimal flex, just to translate a good sensation back to the rider. It's not all new though, the pushrod oil seals have part numbers that date back to 1936!"

The engineering that goes into the bikes isn't something you can really appreciate from your sofa, and it's only once you can have a poke around the machine it begins to dawn on you the sheer amount of work that has been done. Öhlins forks feed through custom-built, off-set adjustable yokes, and WorldSBK spec Brembo calipers bite down onto brake discs the size of dustbin lids. And that's before we’ve reached the swing arm, a piece of engineering work so pretty, it wouldn't look out of place in the Tate Modern. Behind it all though are the bones of a stock Road Glide, and even the engine is extremely close to the unit you can slot in your Harley at home.

"We start with a 131ci crate engine, which actually fits in any one of the heavy tourers on the stand here. You can order them and buy them and have them fitted at the dealer if you want. Obviously, for what we're doing, we're asking so much more of it. We do a lot of hands-on mods’, piston work, the con-rods, and crank... we go through it all. The aim is to make an engine that can race at very high revs for a long period of time. But the overall bore stroke geometry, that sort of stuff is exactly the same as crate engine".

With all that work poured into the 2022 machine, I was wondering why it was taking centre stage in the NEC and not tucked away getting fettled for next year, although Dave advised, this bike's racing days were numbered. "This bike is actually going in the Harley-Davidson Museum and we’re building two new KotB bikes in January. The Frames of next year's bikes are actually waiting for me in Milwaukee!"

"Compared to the original [2021] bike, we made huge leaps this year. This bike is actually five seconds faster than the old bike, usually, if you're finding two to three-tenths a year, you're happy. Yeah, we found five seconds."

I didn't need to get up close to the race bike to know I was a fan of the racing in the King of the Baggers, the videos on YouTube sorted that out. What I didn't appreciate was the amount of custom, top-level engineering that goes into each one. There is a common misconception among many bikers that Harleys are old, outdated, and anything but high-tech. That is definitely not something you could say about Big Blue. If you say it on stage at Motorcycle Live, congratulations, you got close to quite possibly the trickest racing machine in the building.

Year/Make/Model

2022 Harley-Davidson Road Glide Limited

Vehicle Weight

620lbs. (281kg)

Fabrication

Stock bike hand built into race bike in Milwaukee, WI by H-D Technical Specialists.

Engine

Screamin’ Eagle 131R – Race modified Screamin’ Eagle Milwaukee-Eight 131ci Performance Crate Engine – Twin-Cooled.

Year/Type/Size

2022 / 45deg Pushrod V-Twin / 131ci (2152cc)

Builder

Harley-Davidson Motor Company

Cases

OEM

Cylinders

Screamin’ Eagle 4.310" Big Bore Cylinders

Heads

Race Modified Screamin’ Eagle Milwaukee-Eight CNC Ported Cylinder Heads

Rocker Boxes

OEM

Cams

Screamin’ Eagle Race Cam

Throttle Body

Prototype Screamin’ Eagle Throttle Body

Exhaust

Screamin’ Eagle Race 2-into-1 Stainless Steel Header and Titanium Street Cannon Muffler by Leo Vince

Air Cleaner

Screamin’ Eagle Race Carbon Fiber Heavy Breather Extreme with Custom K&N Air Filter

Transmission

Screamin’ Eagle Race Modified OEM Transmission

Year/Type

2022 / 6-speed Manual

Gears

OEM Gear Ratios (First 3.34, Second 2.31, Third 1.72, Fourth 1.39, Fifth 1.19, Sixth 1.00)

Clutch

Screamin’ Eagle High Capacity Clutch Kit (10 fiber clutch plates, 10 contact plates, 3-1200 Newton clutch springs)

Primary Drive

Chain

Frame

OEM

Year/Type

2022 / Steel Weldment

Rake/Trail

26deg / Variable Trail (custom Screamin’ Eagle Racing adjustable triple trees)

Suspension-

Screamin’ Eagle by Ohlins FGR250 Bagger Front Fork

Screamin’ Eagle by Ohlins Remote Reservoir Rear Shocks

Front-end

Wheels, Tires, and Brakes

Front

Builder/Size

Core Moto Apex 6 Forged Aluminum (made in USA) / 17x3.5in.

Tire/Size

Dunlop Race Slick KR448 / 120/70R17

Calipers

Dual, Brembo GP4-RR P4 32/26 Billet Monobloc 108mm Radial Mount

Rotors

Dual, Brembo Pistabassa Superbike T-Drive Rotor, 330x6.75mm

Rear wheel

Builder/Size

Core Moto Apex 6 Forged Aluminum (made in USA) / 17x6.0in.

Tire/Size

Dunlop Race Slick KR451 / 200/60R17

Caliper

Brembo Rear Caliper Billet 2-Piece P2 34mm

Rotor

Brembo HPK Supersport Floating Brake Rotor, 300x5.5mm

Paint/Graphics

Custom H-D Screamin’ Eagle design by CPV Paint & Graphics

Plating/Polishing

NA

Accessories

Front Fender

Screamin’ Eagle Carbon Fiber Racing Front Fender

Rear Fender

DTF Carbon Fiber

Gas Tank

OEM

Dash

AiM MXS 1.2 TFT Data Logger

Gauges

(in dash)

Handlebars

Custom Harley-Davidson Racing Designed, 1.25" to 7/8" Tapered

Grips

ODI Ruffian

Hand Controls

OEM

Foot Controls

Custom Harley-Davidson designed Racing Mid-Controls

Taillight

Single LED Rain Light

Seat

Custom Screamin’ Eagle +4" Stepped Buttstop design, manufactured by Milsco

Additional Harley-Davidson Genuine Parts & Accessories used

Screamin’ Eagle Pro High Volume Oil Pump & Cam Support Plate (62400260)

Screamin’ Eagle Performance Spark Plugs (31600085)

Screamin’ Eagle 10mm Phat Spark Plug Wires (31600108)

Screamin’ Eagle Smart Tune Pro Automatic Tuning Module (41000445A)

Screamin’ Eagle SYN3 Full Synthetic Motorcycle Oil (62600031)