Metric Thunder Report: Racing in Bonneville

Thunder Bob is packing up his custom sleds and heading to the the International Motorcycle Speed Trials by BUB. He plans on entering Thunder Bike 2, the 125 cubic inch Vulcan Muscle Cruiser, in the Run What You Brung class.

Special Report

We have an excerpt from Bikernet and the 5-Ball Race Team on their racebike build. In this session they add a D&D Performance exhaust pipe. At Thunder Radio we will be following along with the team and their effort Worlds Fastest Panhead title. Bikernet is building a bike specifically designed for a land speed record attempt.

Dave Rash, D&D Boss, sent a package of pipe to Bikernet HQ for the assembly and fit of the Assalt Weapon.

We broke a record the first time out, but now we’re getting serious.

We are building the exhaust pipe system for an Accurate Engineering 120-inch Panhead, in a U.S. Choppers, semi-board-track frame. The lovely Valerie Thompson, a professional Destroyer class drag racer, is our rider, and we will build the bike to fit her like a glove. To see all of the build point your browser to

Exhaust Pipe Chapter #14

Once the engine was in place I needed to make my custom set of D&D pipes in a couple of days, or die trying. The buzz was high for the Bub’s Bonneville Motorcycle Speed Trials. Dave Rash, the D&D boss, called me with the exhaust formula. He’s a speed and performance nut. D&D dyno tunes every exhaust system they make. “Don’t run 1 ¾ exhaust at all,� Dave started. “Start with 1 7/8-inch pipe for 14 inches and step up to 2-inch until each pipe is exactly 35 inches long.� Then I’m supposed to slip on and weld on a carefully designed and ground collector. Finally an empty, slip-on megaphone needed adapting

This system has been tested to give me maximum hp at 6,500 to 6,800 rpms.

We’ve discovered that the two into one systems generate 20 more horses than single exhausts.
Dave Rash, The Pope of Pipe

I was wrapped as tight as a .45 magnum shell the first day of pipe making. Bonneville was looming like a 10 pound ballpeen hammer over my thumbnail. We were scrambling, making calls, counting our pennies, praying for surf, and yet it was all going reasonably well in our over heated shop—unless any obstacle jumped in the way or unforeseen delays slowed progress. It was smoking that day as temperatures on the coast glide toward the 90s.

Enough sniveling, I had pipes to build, wiring to figure out and hydraulic lines to make. We were bugged by our first two- into-one attempt and I didn’t like how far they stuck out in the wind. I was burnin’ daylight and grappling with decisions. I like to make a solid plan, after thorough research and go for it.

I questioned my plan, called Berry Wardlaw and Dave Rash for info, bobbed and weaved into action again with the best data at my back. We needed the pipes on and the bike plumbed and primed by Thursday when Berry Wardlaw, from Accurate Engineering flew in for tuning and dyno work.

Man-oh-man, we’re cooking with hot grease and lots of garlic.

I needed to jump back into the shop. My nerves were shot, my head over-loaded with info and not enough time to pressure me to the deck.

This is what we came up with, the first round.

I’m damn proud of you guys!
Dave Rash said when I e-mailed him this image.

We worked for about six hours, stood back and proudly admired our completed, high-tech, D&D supported and designed, stepped megaphone system.

Just then, in walked the queen of Bikernet, the gracious Sin Wu. The dog bowed to her then licked her leg as she passed and commented,

What about Valerie’s leg?

I immediately knew what her highness was referring to. I had that aspect and obstacle to exhaust system planning engrained into my brain. Then, just an hour prior to system completion, I spaced.

Modified Pipe Adjusted For Valerie Thompson,

Dave Rash, the D&D Boss, suggested the lift and the line of the frame called to us, “Aerodynamics.� We lost sight of Valerie’s dainty foot being grilled. We adjusted and straightened out the system to a mere 3-degree lift.

Rick Krost, the boss of U.S. Choppers, drifted into the shop last night, picked up the pipes for precision TIG welding.

To see all of the build point your browser to

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