Yamaha RD400 custom

Yamaha RD400 custom
Today’s post is courtesy of Moto Retro Illustrated magazine, with words and photos by Andy and Lindsay Mauk.

To some, acquiring a bike for your wife might sound as simple as buying her a set of golf clubs, or maybe adding some space to the garage as an anniversary gift.

But this was different. Way different. The request came from my wife Lindsay loud and clear. “I need a bike I can ride on the street,” she said. It was true. After years of riding dirt and racing supermoto, Lindsay was neither content nor deserving of a sissy-bar lifestyle. She needed her own streetbike.

While most people would’ve simply headed straight to the classifieds, my instinct was to put together something we already had. A quick search of my mental catalog turned up the answer—a ’78 RD400 my buddy John used in college and had “stored” in a barn to rot.

Lindsay and I went to grab the barn-fresh bike. It’d been a few years, so I wasn’t sure what to expect. I think Lindsay was just excited to pick up her new ride. But here’s where some of the story details changed. “Stored in a barn” turned to “stored outside a barn.” And “seized engine” morphed into “single-piece crankshaft made of rust.” It was ugly, and we hadn’t even found the cylinders yet. After some hunting and gathering we loaded everything up and headed home, with a stop at a local carwash to rid the bike of multiple layers of bat guano.

Step one was to be this: Strip bike completely, rebuild engine, and repaint chassis and bodywork. Then reassemble. Step two: Present bike to Lindsay and go riding.

Yamaha RD400 custom
But somewhere between steps one and two the plan changed, the change brought on via a call to my buddy Rick Goldberg.

Me: Hey Rick, I’m gonna put John’s RD together for Lindsay. Wanna help?
Rick: “Sure! Bring it to the shop. Sounds like fun!

Rick’s shop isn’t extravagant, just an attached two-car with no cars, but it did have some cool tools—metal lathe, welder, mill, and other fabrication bits. The problem here is that Rick really likes to use his tools, and suddenly we’d gone from “restore” to “re-engineer,” the photo of a Ron Wood YZ400 dirttracker on his wall providing some direction. With a concept in mind and a tight schedule to adhere to (Lindsay wanted to be riding by spring), we got to work.

As with most of our projects, the dual MOMBA experiences being two of the most recent, work began on the chassis. Rick and I cast longing looks toward the Sawzall—Milwaukee’s finest “cut-anything” tool—hanging on the wall, but first we needed parts. Rick’s shop already contained a dirt-track tail section and fuel tank, which helped provide an image of what we were actually about to create. Other than those bits, everything else was yet to be determined. I had some old RZ350 rotors left over from my early roadracing days, and we thought they’d work fine, especially bolted to RZ wheels, which of course we didn’t have. A quick call to friend and two-stroke connoisseur Dan Slattery and JACKPOT! Dan not only provided wheels, but an RZ fork, triple clamps, swingarm, brakes and a set of worn-but-workable Toomey chambers.

Fitting the RZ front end was relatively easy. Upper triples bolted right on with new tapered bearings, Progressive springs were installed to keep it taut, and a Kawi ZX-7 master cylinder provided the right valving for the RZ brakes—more than enough braking force there.

Yamaha RD400 custom
In back, the RZ swingarm bolted up just fine with some trimming (Sawzall!). We’d planned to simply weld on some shock mounts, but Rick, having just read Tony Foale’s Motorcycle Handling and Chassis Design book, convinced me that a monoshock system was the way to go. A quick scavenge of parts revealed a tub full of dog-bones and hardware, and an FZR600 shock. A couple sketches, some concept overview and a small leap of faith later we were grinding, cutting (Sawzall!) and mounting our way to a mono-shocked, RD400 heaven.

The monoshock system also allowed us to simplify and lighten the bike’s chassis even further. Without the need to hold the upper shock mounts, the subframe need only hold Lindsay, so the Sawzall came out again and the stock subframe was gone, a slimmer, trimmer sub taking its place. One of my favorite features on this bike is the “see through” effect in front of the rear wheel.

With the chassis done, the final major cosmetic piece—the fuel tank—remained. The stock RD tank was way too big, so we needed another, and shortly found another, smaller Yamaha tank that worked perfectly with some minor fabrication. To this day we have no clue what model it’s from.

Then we dug into the engine. Cases were stripped and coated, and after Supreme MOMBA Wes Orloff donated an old RD ex-race engine from his early racing days, we had plenty of good-condition internal parts, including cylinders and crank. In addition to the 350 engine’s upgrades, the Toomey exhaust and some Emgo K&N knockoffs, the motor is basically stock. I put an equalization tube between the two air filters to keep it running smooth, and jetted it to accommodate the pipes and filters. Porting is stock, as is the tranny. The almighty dollar kept us on a cheap path with the engine, but five years after the fact, it still runs like a champ.

Yamaha RD400 custom
The bike is loud, still riding and peaky. Wheelies are practically unavoidable (and a big fine here in Milwaukee), and you wouldn’t want to spend more than an hour on it. But it is an awesome ride. It attracts a sh*tload of attention wherever it goes, and I never get tired of looking at it. It’s held up throughout the years and has inspired many more projects. In 2005 it took home the “Cool As F!@#” award at our local Rockerbox streetparty.

Lindsay agrees. “I absolutely love that bike,” she says. “And to think all I wanted was a streetbike that was fairly clean and reliable.

“I watched this bike get built,” she adds, “so I was accustomed to the shapes and the silhouette. But nothing could have prepared me for the outcome. I was shocked! Rick and Andy went above and beyond the call. I am always honored to ride this bike—it’s beautiful, fun and totally kicks ass!

“It’s not a bike I can sneak around town on. People hear those Toomey pipes, and with the bike’s striking look, folks seem very intrigued by it. When waiting at a light it’s not uncommon for the person in the car next to me to roll down the window and ask me what kind of bike it is. These brief stoplight conversations usually end with, ‘Wow, cool!’”

“Here’s my favorite memory of the bike. Andy took me over to Jones Island (light traffic) so I could get used to the thing. After several trips around, we stopped for a break and Andy asked me, “Did you come onto the pipe?” Now, I’ve been around bikes and garages all my life, and I had no idea what he meant. It’s a strange question, one that can be taken many ways, even if asked by one’s own husband! Andy saw the puzzled look on my face and explained. I told him wasn’t really sure. In my next practice ride, I discovered I hadn’t yet hit the powerband, cause on that bike, YOU DEFINITELY KNOW WHEN YOU HIT IT! I fell in love with that bike right then and there. I guess coming onto the pipe will do that to a person.

“I really am one lucky girl!”

[Thanks to Mitch Boehm. Get your subscription to Moto Retro Illustrated here.]

Yamaha RD400 custom