Flat Track Tribute: Harley-Davidson 1200 Street Tracker

A two-wheeled tribute to a father and son’s flat track memories…

For many of us, the love of motorcycles gets handed down from father to child. That was certainly the case for California’s Bill Brosius (@cleanedwithqtips), who grew up on the back of his father’s Harley-Davidson.

“We would ride all over California and neighboring states. Every few years we would ride cross country. We loved flat track racing!”

By the time he was 13, Bill was grooving tires and swapping sprockets at the local dirt track — once he even got to push a race bike to the starting line at the Sacramento Mile alongside legends like Jay Springsteen, Chris Carr, and Scott Parker!

Around the same time, a neighbor was kind enough to teach him the finer points of trials riding and Bill was soon hitting the local MX track, even getting some seat time on another neighbor’s ’89 Honda CR500!

“He knew I had good throttle and clutch control and the urge to go fast, so he let me ride it, lol! I would bump start it for a few months till my 12-year-old 115 lb. body could figure it out.”

Fast forward to today, and Bill has owned some 33 bikes of all kinds, doing most of the maintenance and modification work himself. He’s raced AFM; he’s an instructor for Z2 Track Days; and with no kids, he and his wife devote their free time to motorcycle-related trips, travel, and fun.

The 2001 Harley-Davidson Sportster you see here is a tribute to Bill’s father and their shared love of flat track racing — an especially poignant tribute as his father has stage 5 dementia and those memories are much of what he retains. Says Bill:

“Building this bike brings back old stories and I find that he loves to just sit and watch me wrench when he is in town.”

This is a true form follows function build — nothing on the bike is just for looks. The front end is an Öhlins unit from a Ducati 1098, and the bike also boasts parts from the an Aprilia RS250, Kawasaki ZX, dirt track machines, and an array of components custom-made on Bill’s mill and lathe.

“The concept is performance. It just so happens to look badass!”

Bill says this 1200 Sportster street tracker rides like a supermoto in the canyons and even better on the racetrack:

“The bike will sit sideways in and out of the corners with ease… You get a real feeling of being that flat track racer that you idolized as a kid.”

Still, the best part has to be Bill’s father’s reaction every time the V-twin fires up through the big dual Supertrapps:

“When I start the bike just for a second, I hear…the rustling to get to the door of a walker hitting everything in its way and my ma yelling at him to slow down so he does not fall over! He gets very excited when talking about it and loves to see the progress throughout. He is a major Harley-Davidson fan, and this build is for him and our flat track memories.”

Below, we get the full story on this incredible tribute to a father and son’s shared memories.

1200 Sportster Street Tracker: Builder Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

I grow up on the back of my father’s bike. We would ride all over California and neighboring states. Every few years we would ride cross country. We loved flat track racing! Chris Carr, Scott Parker, Jay Springsteen, Steve Morehead, and Matt Wait were just a few of my heroes. This is back when they ran the 883 class. I was lucky enough that my dad knows one of the mechanics at Modesto Harley-Davidson named Bob White. I was about 13 years old, and he taught me to groove the tires and change the sprockets at the local races. One of those races at the Sacramento Mile I got to push the bike by myself out to the starting line in front of the crowd. We were front row — I had Springsteen, Morehead to my left and Parker, Carr to my right! By far the best feeling I have ever had in racing. I have always wanted to race them but never had the pocketbook or resources to support this dream.

My neighbor was a trials rider, and he would try to teach his son all the slow techniques in our court, but the son showed no interest. I would be out there every time I heard the bike start to mimic everything he was doing. He would have me do figure eights for hours as tight as I could get them and when I was done I would practice balancing in place with my head forward. When I got the balancing down, I could practice on his Gas Gas that he had bought from Jordi Torres, the world champion.

After a year or so he broke down and asked my parents if he could take me out. He generated a contract to release liability in the case that I got hurt. From there we would go out every weekend to Carnegie Hills and I got to ride the world champion’s bike.
My first bike was a 1981 Fantic 300 trials bike. I did some competitions and podiumed. Now I knew how to go slow and it was time to hit the MX track! I road my trials bike out there and did okay for the six inches of travel that it had…

We had another neighbor who had moved in and would trail ride with us, and he had an old 1989 CR500. His rule was “if you can start it, you can ride it.” He knew I had good throttle and clutch control and the urge to go fast, so he let me ride it, lol! I would bump start it for a few months till my 12-year-old 115 lb. body could figure it out. He helped every now and again. From there I got fast or what I thought was fast!

I worked my butt off and got a loan to get something I could put the power to the ground. That led to buying and selling my way into the hobby. I have had 33 different bikes from all walks of life. Dirt to street to touring to customs I have had it all. I was always a hands-on kid who was too cheap to pay for a mechanic so I would try and work on them myself. After doing this for so many years, I got better. I found a good deal on a mill and a lathe, so I toyed with the idea of milling out my own parts to make a completely custom bike and this is the one I landed on.

I raced AFM for a few years and I do hare scrambles with my buddies to this day. I am also an instructor for Z2 Track Days here in California. I am married to my lovely wife who supports me in every way with this dream of mine. We do not have kids, so we are able to throw on the helmets and ride to the coast for lunch or wherever the wind takes us. One of our favorite things to do is travel and we try to incorporate motorcycles into every trip. Getting to do a trackday at Phillip Island in Australia and touring the Yamaha factory in Japan along the side of my wife is what life is all about!

• What is the make, model, and year of the bike?

2001 Harley Davidson Sportster.

• Why was this bike built?

I built this bike for two reasons. Watching flat track with my dad through the years and to finally get the bike that I have always dreamed about. Second reason is that my dad got diagnosed with stage 5 dementia and the memories are all he is retaining. Building this bike brings back old stories and I find that he loves to just sit and watch me wrench when he is in town.

When I start the bike just for a second, I hear two things. The motor turns on for literally 2 seconds, then the rustling to get to the door of a walker hitting everything in its way and my ma yelling at him to slow down so he does not fall over! He gets very excited when talking about it and loves to see the progress through out. He is a major Harley-Davidson fan, and this build is for him and our flat track memories.

• What was the design concept and what influenced the build?

I have always wanted a flat track motorcycle and between my good buddy and myself we have a few parts laying around along with a mill and lathe. The concept is performance. It just so happens to look badass! Everyone tells me that the paint should be Harley orange, but I want something that nobody else has.

The bike has and will keep evolving because the more I stare at it the more things I want to shape up. This bike took me a little over a year to build it so far. Rims, motor and rear sets are on radar.

• What custom work was done to the bike?

This bike has a Ducati 1098 Öhlins  front end with bits of Aprilia RS250, Kawasaki ZX, dirt track, and custom-made parts. It seems like the littlest thing you want to change turns into a huge project. Thanks to Motion Pro for building me cables to adapt everything and Galfer for the brake lines to tie in the braking system.

You cannot have Brembo brakes on the front and not the rear! I have not found any quad caliper mounts for this make and model, so I had to make it all myself.

I went with the Storz tank to show the real commitment to the build. I think the tanks, as pricey as they are, are well worth it in the end. Now that I have the tank on, the forks hit which led to changing out the triple clamps.

I originally milled out spacers and inserts to adapt the Ducati triple clamps with a Monster upper but after making handlebar stops, there was too much going on. I felt like it needed to be a solid piece of billet and that’s what I did.

• Does the bike have a nickname?

In a guy’s mind we think chicks love the revving, speed, and all the testosterone driven projects… In the real world these things only attract men. So, we named it “The Brief Dropper.” Sadly, no panties have dropped in the making of this motorcycle…

• Can you tell us what it’s like to ride this bike?

The feeling is amazing! Knowing you built it, is something in itself. There are no parts on this motorcycle just for looks. Everything is made for performance and the ride follows exactly that. This is like riding a supermoto through the canyons and even better on the racetrack! The bike will sit sideways in and out of the corners with ease.

When going to the coffee shops you are blessed with great people giving you the thumbs up the whole way. I love the sound of the Supertrapps! They are quiet at low rpm, then have the perfect tone at speed. You get a real feeling of being that flat track racer that you idolized as a kid. I wish I could’ve built it sooner so that my father could’ve had a chance to enjoy the experience.

• Was there anything done during this build that you are particularly proud of?

I mostly like the simplicity. The bars are clean of buttons and wires. Everything is hidden or built into other parts to conceal them. Another awesome feature was adapting the brakes. It was a fun part for this build to make the parts to align everything and actually having a Harley that can stop is really cool!

• Parts Brands & Mentions

Öhlins Racing, Saddlemen, Brembo, S&S Cycle, Progrip, Protaper, Supertrapp Industries, Motion Pro, Z2 Trackdays, Harley-Davidson

Follow the Builder @cleanedwithqtips