The interest in the DTRA's Vintage class grows with every year. Four-strokes and two-strokes are mixed on the track, but split into two championships, and Sean Kelly proved you didn't need anyone's idea of a typical flat tracker, or a big budget, to win the two-stroke title, as he did in 2019. Here Sean shares the story of his Suzuki TS400. (Action photos: Braking Point Images)

Motorcycles have always been the family trade but not always in the blood. As a third-generation motorcycle mechanic, I am the first of our family to ever race one. It all started in 2014 when I volunteered to marshal at a DTRA event in hopes of getting into the sport. Standing only feet away from the bikes tearing down the half-mile track in the rain at Amman Valley, I was hooked.

I raced the whole 2015 DTRA season in the rookie class on a Yamaha YZF426 not having a clue what I was doing. It took me until my third race to get the suspension lowered for flat track. Through sheer grit and adolescent eagerness I managed to win the Rookie championship. I raced the next season in intermediate, but a road incident left me with a broken femur and shattered wrist. I was out of the sport for just over a year. I came back to the Inters [the DTRA's Intermediate class, between Rookie and Pro] and raced the last two races of 2017 and then another full season in 2018 on my Yamaha 426, managing to finish 4th in the championship meaning I was going in the Pro class for 2019.

I’ve been lucky enough to meet some great people during my short racing career, one who made the most impact is Mike Fisher. We shared the pits together in 2015 for our first race. A salt of the earth kind of guy and a great mentor. He went on to race and win the vintage two-stroke flat track class on his Champion Bultaco 350. This is the gentleman’s class, proper machines and well-dressed folk racing for the love of it.

I raced Mike’s Bultaco a couple times over the years and thrill was immense, the sound, smell and vibration was nothing on the modern bikes. Since my accident I felt I’d lost my momentum in the modern class and knew I would struggle in the Pros, so wanting to race and still enjoy it, I needed a new challenge and the Vintage class was calling.

My dream bike would have been the Triumph T100 500cc twin, but the prices of vintage bikes have gone through the roof, so it wasn’t feasible. I was on eBay every lunchtime at work looking for a Vintage project, and then I saw it. A 1973 Suzuki TS400 from the States. The engine was loose in the

frame and it was missing the CDI, the tank had many dents but my winning bid was £995 so I was happy enough.

On stripping the bike I found two frame mounts to be broken but everything else was okay. I took the engine down to Mike Fisher’s farm. He has a fantastic workshop and knows all there is to know about two-strokes. We stripped the engine to find the piston was nearly new the ring gaps were perfect and, luckiest of all, was discovering the bottom end had been rebuilt at some stage with what looked like a new con-rod.

Back at my workshop I repaired the frame and refitted the engine. I left the front-end stock, as the wheel was 19in already, so I only had to rebuild the forks and centre the front wheel so it had room for the Dunlop DT tyre. I left the rear wheel 18in to start with but eventually rebuilt it with a 19in rim to fit the correct DT tires. I found a used CDI unit, connected the necessary electronic components for the bike to fire, kicked the bike and the spark was good. After putting the stock,

rebuilt carb, air box and exhaust back on it was ready to be kicked over again, this time with pre-mix. Second kick the old Suzuki fired into life and filled the workshop with smoke. It was running good and sounded solid. After quick test run up and down the side lane to check the gears and clutch, I felt it was ready for a race.

I took the bike to Rye House for a practice day and soon found the standard rear shocks were awful, bucking me everywhere. A pair of slightly longer Hagon shocks fixed this issue and gave me the drive out the corners, being longer also meant less rake for quicker steering.

The next issue was the tickover screw started winding itself in further every lap, until I was coming off the back straight still on the throttle. I had to bin the bike into the air fence, snapping the clutch lever but no major damage. I found the issue the hard way, but nothing some lockwire couldn’t fix. I was pleased. The bike was powerful enough to be competitive and Japanese enough to finish the

race as well.

First race out with the DTRA at King's Lynn I manage a third place finish in the final. This motivated me to get the 19in rear wheel built. I had the bike dyno tested and found it made 27.5bhp at 5000rpm. It was enough for short track racing and I raced the whole 2019 season with a mostly stock Suzuki TS400. It never let me down and after the first race I won every other national vintage two-stroke race of 2019 taking the championship. Along the way I beat a lot of the big Triumphs and had the most fun I’ve had racing flat track. The sounds are fantastic the feeling of lining up on the grid with a 1000cc Harley on your right and a 750cc Triumph on your left, with Hubert Bastie’s two-stroke Husqvarna firing pre-mix from the front is incomparable to other race classes. It has been an honour and a privilege to race with the DTRA alongside so many great riders from around the world. A big thank you to those who make it possible.

Sean's Suzuki was given a lick of paint for 2020.

#VintageDTRA #SeanKelly #VintageFlatTrack #DTRA #DTRA2020 #HubertBastie #Suzuki #Twostroke #MikeFisher

Following up on the interview with Jeffery Lowery, here are some AFT race bikes with his wheels.

Above: Cole Zabala's RMR Honda 450.

If you haven't done so already, read our Jeffery Lowery interview.

Ryan Varnes' Kawasaki Production Twin.

Brandon Robinson's Roof Systems Indian FTR750

Trevor Brunner's Honda CRF450

I came across Jeffery Lowery and his CNC work on social media, and got in touch for an interview. GI

How old are you and where are you based?

I am 23 years old, based out of Saint Louisville, Ohio.

How did you learn your craft?

I have been around machining my entire life, but I learned the fundamentals of CNC machine programming through a 4 month trade school.

When did you start making flat track wheels?

My dad was self-employed in 2017, working in his machine shop. I helped him design and make our first flat track wheels then, while I was living two hours away. In 2019 my dad got a job outside of his shop, and in January of 2020 I moved back close to home. I improved the wheel designs, expanded our applications, and used my dad's shop to start this business. In May I bought a new Hurco CNC mill, and in November 2020 I resigned from my 'real' job to be fully self-employed.

I am the only person working on this business full time right now, but my girlfriend Gabrielle, my mechanic Kevin, my dad, and a few other friends all contribute a lot.

Please give us a basic outline of the production process of a wheel.

The wheels are rotary forged and turned in a lathe before I buy them. When I purchase the wheel blanks, the outside rim section of the wheel is finished. I use a CNC mill to machine the wheel pattern throughout the center of the wheel.

The hubs start as extruded aluminum bar stock. We cut it into pieces with a band saw, turn the profile and bearing bore in our CNC lathe, and machine the flanges in our CNC mill.

Our wheels are then anodized, which we outsource.

Who designs the wheels?

I personally do all of the designing and programming of the wheels.

Some of the spokes look very thin, do you do FEA calculations?

I have used some force simulation software, but determining exactly what is strong enough is not a straightforward answer. The wheel is experiencing a lot of very dynamic forces as it is spinning at a high rpm, the motorcycle and rider are on suspension, and the forces coming from the track are dampened by the pneumatic tire. Conceptualizing those forces is not extremely difficult. Calculating those forces is.

I used my best intuition to design the lightest wheels that I was personally comfortable using. I made this 'weak' set of wheels and I use them on my bikes. After hundreds of laps on rough tracks, those wheels are still straight and true. All of the wheels sold to customers are legitimately stronger than my personal wheels. Lowery Racing wheels are for off-road use only, and I have not received any complaints.

How much do the wheels cost and what is the usual waiting time?

The base price of a wheel body is $600, hub assemblies range from $150 to $520 depending on the application. We are building an inventory of black wheel products that we will be able to ship the next day. Any different colors are made to order, and most orders are completed within 4 weeks.

We are currently working on a website and intend for it to be live in January of 2020. This website will make the information easy to find and simplify the ordering process.

Do you race yourself, please give us details of what you race and where?

I have raced flat track since I was 4 years old. So far, the highlight of my career was winning the AMA Dirt Track Horizon award in 2013. I intend to race select events of the AFT Production Twins class in 2021.

I did not race professionally in 2020 in order to focus my efforts on this business. My race program will have more resources in 2021 than ever before, so I am excited to get back at it. We do not plan to race the full 2021 AFT schedule, but I really believe we will compete for wins this year.

What other products do you make?

We have been completely focused on wheels so far, but we plan to expand to triple clamps, heavy clutch baskets, and other flat track parts in the future.

Who are the highest profile customers you have?

We work with some of the highest profile teams in American Flat Track. Lowery Racing wheels were on bikes that won AFT Super Twins, Production Twins, and Singles races in 2020.

We will be working with even more teams in 2021.

What plans do you have for the business for the future?

I’ve always seen flat track as an under-served market, and this business is here to meet that demand. The main focus right now is to further expand our wheel offerings, but there are more things coming in the future. We are sharing our journey through our Instagram and Facebook page, give us a follow to see the fun!

See more at @lowery_racing on instagram