Mudflap Girl Part 4, the Spitfire Frames to Rollers

Suddenly we’re smoking on the Mudflap Girl FXRs, but the week after I received the frames, I had to jump a plane to New Orleans and ride a Victory to the Smoke Out. I was itching to work on these bikes.

I survived the Smoke Out, and since I just spent 1000 miles in a Victory saddle, I was motivated to get back in the wind. We looked down the barrel of the ticking calendar as I returned from the East Coast on Sunday and Monday the 27th of June I stepped back into the Bikernet shop and faced two Mudflap Girl FXRs on lifts ready to rock. I dove in making lists and started to assemble my frame and the Spitfire girder front end.

Building a bike is like falling in love. We all have our dream of the perfect woman, and each time I build a bike, that notion is the driving force. I’m building the perfect romance, with all the best intentions. I want this one to last forever, take me anywhere I want to go, and be my Mudflap girl baby in spirit, appearance, and function.

I would imagine the same mental scenario applies to a home building architect. In fact, we have focused some of our efforts on creating a vintage motorcycle coffee shop in the front of our building, Bandit’s Barista. Talk about a daunting process involving several city agencies. Let’s leave that one alone. Sin Wu came to a meeting this morning and immediately quizzyness engulfed her and she was forced to leave. “It’s too daunting,” she said.

We are so fortunate to be able to rely on our friends and compadres in this industry and build whatever motorcycle we want, then go for a ride without severe governmental restrictions. Meanwhile, back in the shop, I was completely astonished at Paul Cavallo’s talents and shop capabilities. He designed and manufactured every element of this classic girder front-end. As I installed his internal fork stops and began to assemble the front end with the Foose-designed MetalSport 2D wheel, I was constantly blown away at every intricately machined piece.

Although Dr. Willy bitched about the top motormount on the frame, I didn’t have a problem with it. It just forced us to face another brief obstacle, which will ultimately create a very cool linkage issue with a 7/16 pivoting rod end on the top like most FXRs.

But I’m getting ahead of myself. I installed the fork stops, then the Biker’s Choice neck races, the Timken neck bearings, and the Metal sport front wheel on the Spitfire ¾-inch axle. Paul set up his frames to take stock Harley 2000-2007 front and rear brakes. We are going to use factory brakes on my son’s FXR, but I’m running with GMA brakes currently manufactured by BDL.

I had to come up with a mounting system using Paul’s stock H-D brackets. It was a trick but worked out, with brass rod and steel spacers. I messed with it for a couple of hours. Ultimately the GMA caliper was centered over the MetalSport rotor and in a terrific position for bleeding.

Then I started to install the girder rockers and bronze bushings. I was careful to grease every component, and again I was impressed by the precision fit with each bushing and axle. I installed the trees on the fork stem and rolled closer to installing the girder structure. Everything just slipped together.

Unfortunately, I was missing one element of the front end, the brackets holding the shocks in place, so I shifted to something fun, installing mudflap girls on the Spitfire side panels. They make these Zeus fitting fastened aluminum panels out of street signs. The mudflap girls came from 2Wheelers in Denver, but the Arlin Fatland and Donna team is currently headed for Sturgis to the rally, which reminded me that Sturgis is just around the corner. If I had another month, we’d be riding the Mudflap Girls to the Badlands.

Next, I needed to install the rear MetalSport wheel and driveline. FXRs are tricky in this regard. The entire driveline from the engine to the rear wheel needs to be installed at the same time. We started with the swingarm, using the Custom Cycle Engineering swingarm axle and retrofit kits. Here’s what CCE says about these conversion kits.


Custom Cycle Engineering has developed a swing arm conversion kit that replaces the stock Cleve Bloc style swing arm bushings with spherical bearings. The conversion covers all the FLT and FXR models from 1980 to 2001. The swing arm conversion kit coincides with Harley-Davidson’s change from the Cleve Bloc bushing to a spherical bearing in all the 2002 and up FLT models.

The conversion over to spherical bearings in the early models dramatically changes the handling and tracking of all the FLTs and FXRs. The sticksion at the swing arm pivot is greatly reduced with the new spherical bearings. This allows for the swing arm to react quicker to any harsh road conditions, keeping the wheel in contact with the road. The use of spherical bearings also helps negate any lateral and torsional movement in the swing arm by the shear dynamics of a spherical bearing.

The swing arm bearing conversion kit is one if the positive answers to the inherent ill handling problems of the popular dresser models.

It was easy to install the new spherical bearings using our shop press and the special tool CCE provides with their kits. We pressed them into place with the CCE guide tool and red Loctite. Then we installed the swingarm on the transmission and the whole tamale in the frame, since the oil tank was out for sealing and some flat black protection. Ray C. Wheeler gave me a hand. We slipped the JIMS transmission and swingarm through the back of the frame sideways, then turned it level and aligned it with the frame mounting system. My son scored some used bare aluminum cleave blocks, and I ordered new H-D rubbers from Biker’s Choice. Watch how the rubbers and cleave blocks are mounted. They are like a small four-piece puzzle with guide pins in particular locations.

With the JIMS 6-speed transmission in place, we jacked up the trans for engine installation. With a centered Biker’s Choice front motormount bracket in place and the rubber biscuit we were ready to rock. Willie helped guide us through the process. Willie is a master with FXRs. He’s worked on bikes, and rebuilt engines and transmissions forever. He knows all the tricks.

With the driveline in place, I started to monkey with the D&D pipe mounting, mounting brackets, and mounting the GMA rear brakes. The brakes became tricky, since Paul designed a tougher and wider swingarm, but it worked out perfectly. I’ll get to that puppy in a minute. I noticed that the trans didn’t come with the final seal and locking nut, plus we needed to reach out to JIMS for a proper offset sprocket for the 180 Avon tire. Since this is an 80-inch Evo, I wanted some gearing advice for the 6-speed overdrive transmission.

Here’s what James Simonelli wrote while packing for the Sturgis Rally and preparing for their install facility. Call them quick, if you want an upgrade while you’re in town.


22-51 with normal 37-24 primary is 3.57, pretty lively! In 6th (.86)
you would have 3.07

23-51 37-24 gives 3.42 and 2.94 in 6th. I think that’s where I’d start.

To compare, most stock late models with 70/32 belt and 36/25 primary are
3.15 overall in 5th.

It’s nice to be slightly below 3.0 in 6th for 75 mph cruising. If it’s a
stoplight burner, go the other way.

Baker will be set up in Sturgis on Lazelle performing installs. If you would like your 5-speed modified into a 6-speed, or a special Baker oil pan added to your dresser, set up an appointment soon, and tell ’em Bikernet sent ya.

While I was tinkering with pipe mounting system, I kept forgetting the Spyke Starter and I had to make a few adjustments. I dug around in my spare tubing bin and discovered an actual pipe-mounting bracket, plus I used a piece that came with the shorty D&D muffler. This exhaust system will sorta mirror the bare Bub’s system we ordered for Frank’s Mudflap Girl FXR, very similar, although his muffler is considerably different. It will be interesting to report on the differences.

We ordered a rear sprocket spacer and a dished 51-tooth sprocket from Biker’s Choice. It’s always somewhat a roll of the dice and I try to build a selection of spacers to allow me a variety of spacing options. With the JIMS ½-inch offset 23-tooth sprocket and the centered wheel, the transmission lined up perfectly with my brand new O-ring chain. It had never been removed from the crumbled box after a trip or two to Bonneville. I pulled it free from its container and the bastard was covered in rust.

Chad from JIMS sent me a photo of the mainshaft seal-installing tool. I also ordered the seal spacer, but had an installation question.

“Tech says bevel side faces into trans,” said Chad. “I have attached an image of the
needed tool, #786.” I dug through my special tool bins and found something from JIMS that would handle the trick.

In the meantime, our sheet metal returned from Jim Murrillo, who sealed the tanks with Caswell and gave the exterior a protective primer coat. It was a rush to slip the two gas tanks into place but we ran into a problem with my oil tank. I almost had to take the engine and the trans out of the bike to return it to its rubber mounts. Ah, but we succeeded.

Now all the major elements are in place, but the Sturgis Run is moments away. We plan to load my Sturgis Shovelhead onto our trailer, with the 120-inch Panhead, the Salt Shaker for Mr. Wheeler to ride. We will snap the trailer to the Bikernet hearse and cut a dusty trail in a couple of days. While I’m in the Badlands I’ll be thinking of Mudflap Girls and getting back to the builds. I’m sure I’ll return with more ideas, and next year will be the year of riding FXRs to the Badlands.

Hang on for the next installment as we mount up the Trock-modified CV carb on my ride, and the Mikuni 42 mm on my son’s bike. We have wiring harnesses from Wire Plus, and I have a rare intake manifold from H.E.S. and Branch, that was ported by John O’Keefe. We’ll be rolling close to final assembly as I install my BDL belt drive system and Frank’s mid controls. Goddamnit, I can’t wait.



Biker’s Choice

JIMS Machine



Wire Plus

Branch O’Keefe

Bennett’s Performance


Custom Cycle Engineering

Please follow and like us:
Pin Share
Scroll to Top