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Building a custom bike

The bike takes shape

Story by Bill Kresnak
Photos by Bill Andrews

Bruce Mullins grinds down the raw welds making the fabricated rear section as smooth as possible.

Even while the team at the Skunkworx Custom cycle shop in Columbus, Ohio, is doing the fabrication work on its Skunkworx/Jim Davis custom bike, changes are being made.

Skunkworx owner, fabricator and bike builder Bruce Mullins, and fellow builder Jim Davis, take a long look at the bike's frame. They don't like the straight tube under the gas tank location that connects the top frame rail with the lower downtube, so they cut it off.

They put a curved piece in its place.

"That looks 100 times better than the straight piece we had in there," Mullins says as he admires his handiwork.

Frame modification

Mullins cuts out the stock straight brace and places in a curved piece.

He then welds in the new curved piece

Next, Davis begins putting body filler on the bike, which will take more than five quarts of filler and more than a week's time.

After putting on the filler and sanding it, Davis (left) closes his eyes and rubs the bodywork.

"You have to keep finding the high spots and the low spots," Davis explains. "And it's got to be done by hand.

"The best way to feel is to just close your eyes because your eyes will deceive you. I'll look at a shadow and I'll keep trying to feel the lump" that isn't there, he says.

Mullins hits the bodywork with a fine mist of black paint to take one last look for high spots.

Meanwhile, Davis is glad this part of the project is over.

"There's a lot of elbow grease involved," Davis says. "My shoulder is killing me."

While creating outstanding bodywork with symmetrical shapes and lines is critical in creating a custom bike, the next part of the project will determine whether the Skunkworx has created just a great custom bike, or an extraordinary show-winner: the paint.

The paint also proves to be the most controversial part of the project.

*Removing the engine and drive train*
The team assembles and disassembles the drive train many times during the build to see how everything is working together.	First, the rear wheel is pulled (top). It was during one of these disassembles that the team discovered a clearance problem with the rear fender. Next the transmission is pulled (bottom).		Then, it takes two strong arms to pull the massive 124-cubic-inch (2,032cc) engine (top). Most of the parts are simply put aside on a nearby table (bottom). Amazingly, this entire process only takes about 15 minutes.
*The welding process*
	Mullins, (top left) first tack welds the part into place. Each dot of metal represents a tack weld (lower left). Once he is certain about its placement and shape, he permanently welds it in (top).		After all the welds are completed, Mullins goes back with a grinder to smooth them out (above).
*Building a seat pan*
1) As is the case with most design elements on the bike, Davis and Mullins first talk about how the seat should look. Davis, a former drag racer, is wanting a somewhat small seat with a bump-up to hold the rider on—much like a drag bike seat. They then use construction paper to mock up the design before committing to sheet metal. 4) Mullins and Davis take measurements to make sure the seat is perfectly aligned.	2) Mullins shows his secret to getting a perfectly even design. He first folds the construction paper over in the center. 5) Simple masking tape is then used to keep it in place.		3) He then traces the first half design onto the other half of the construction paper. 6) The support around the seat is made in the same fashion.
*Making things smooth*
Scott Popp joins the team (above). His specialty is the body fill and primer coats.	Here, Popp shows how he applies the body fill to all the crevices (above).		Coat after coat is applied and then sanded down to give the bike a smooth, unblemished surface.
Following the build
Once again, the engine and drive train is installed to see how the project is looking with the new welded-on components.		Then, the frame is stripped bare for the molding and sanding.