Fastest Horse in Town: Rotax 604 Thunderbike Tracker

Thunderbike Champion Texas Chris builds a faster horse… 

The Thunderbike class hails from the early days of UK flat track racing, when one of the sport’s godfathers, Peter “Boastie” Boast, wanted to create a class to suit heavyweight framers and modified street bikes — machines such as the Yamaha/Honda 5oo singles, Yamaha XS650, and Rotax 600s:

“Thunderbikes – These are over 500cc machines, sometimes with custom ‘Framer’ chassis or adapted from road or off road machines. Hooligan standard frame, over 750cc, post (1985)” —DTRA

The class, which precludes modern 450 framers, is known for its style, sound, and community. It remains one of the favorites of Gary Inman, founder and editor-in-chief of Sideburn magazine:

“I’ve raced in Thunderbikes, with a couple of different twin shock Rotax framers, since I started racing in 2005. I love the class. I love the bikes. I love the camaraderie.” —Gary Inman

Recently, we heard from 2021 DTRA Thunderbike champion Chris Jenner (@texaschrisjenner), better known as “Texas” or “Texas Chris.”

“I was born and raised just outside of Houston, Texas. But I’ve lived in the north of England for over 20 years now.”

Texas is a lifelong BMX rider who got into flat track racing through Dirt Quake, started racing in the Dirt Track Riders Association (DTRA) Thunderbike class, and won the 2021 DTRA Thunderbike Championship!

The bike you see here is Chris’s thoroughbred Thunderbike, sporting a Survivor Customs mono-shock frame, shortened swingarm, custom subframe, R6 fork legs, and the 604cc Rotax engine from a CCM 604 supermoto. For this season, Chris decided to give the bike new bodywork, and one sweet paint job courtesy of Paint by Matt:

“We wanted to do something that you’d normally see on a chopper, maybe a bit over the top for a race bike, something that was just a little too nice to take on the track…and then go totally rip it up racing flat track!”

While the paint might look black in the photos, it’s full of blue/green flake that stands out in the light, and the flames are a candy gold with smoky texture. Says Chris:

“I freaking love the cowboy painting (transfer) on the tank; it’s got really subtle crackle texture in it that makes it look like an old oil painting up close. Matt really went all out with this one.”

Indeed! This is one of the sweetest flat trackers we’ve seen, and double-cool that it’s already won one championship, truly earning the its nickname: “The Fastest Horse in Town.” Below, we talk to Texas Chris for more details on the build, with photos courtesy of Paint by Matt, Steven Haddock, and the great photographer of UK flat track, Jon at Braking Point Images.

Rotax Thunderbike Framer: Builder/Racer Interview

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

My name is Chris Jenner. Some people call me “Texas” or “Texas Chris” cause I was born and raised just outside of Houston, Texas. But I’ve lived in the north of England for over 20 years now.

I’m a lifelong BMXer who has only really gotten into working on and riding motorcycles in the last 10 years or so. I’ve put together a few custom bikes. One of the first was a street tracker, which I ended up racing at Dirt Quake. That really got me hooked on flat track! And I’ve been racing with the DTRA ever since, with a few different Thunderbikes.

I work on my bikes out of my new garage behind my house. We moved last year and this old stable building in the backyard was a massive selling point for me! Specially as I had previously built all my bikes in a basement workshop. The garage didn’t look like this when we moved in, but one of my first jobs was refreshing it so I had somewhere to take care of my “horses”!

• What’s the make, model, and year of the donor bike?

Ooooh, tricky one! The first donor bike was my previous 500 Rotax race bike. A custom twin-shock race frame that wasn’t great to ride. But since then it’s had a new monoshock frame, new forks, and another bigger 604 Rotax engine… I guess you could say a CCM Rotax Supermoto is probably the closest thing to a donor, but it’s been changed around so much now it’s barely related to that anymore!

• Why was this bike built?

To go fast and have fun!

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

The bones of the bike have remained relatively unchanged for the last couple seasons. And the plan was to just put together the best Thunderbike I could afford to for racing. I felt comfortable on it last year. So this year I just gave it a refresh with new bodywork and a sweet new paint job from Paint by Matt. We wanted to do something that you’d normally see on a chopper, maybe a bit over the top for a race bike, something that was just a little too nice to take on the track…and then go totally rip it up racing flat track!

• What custom work was done to the bike?

Lots. The frame is a Survivor Customs CCM conversion, with shortened swingarm and custom subframe. The forks are R6 legs with some CNC racing yokes. Just bout every part has either been made or modified by me or a friend. The bodywork is modified and re-shaped “off the shelf” fibreglass…and then the most custom part…my sweet new paint job! (I want to make a big deal of it now, while it’s still all nice looking, before I beat the shit out of it racing!)

You won’t really be able to see in the pictures, but the black actually has bluey/green little flake in it when it catches the light, and the flames are candy gold with smoked texture. I freaking love the cowboy painting (transfer) on the tank; it’s got really subtle crackle texture in it that makes it look like an old oil painting up close. Matt really went all out with this one.

• Does the bike have a nickname?

Me and Matt called it “The Fastest Horse in Town” after a Sturgill Simpson song.

• What’s it like to ride?

It’s awesome. Loads of fun.

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

Putting a race bike together and then doing well on it. Winning races was cool. Winning the Championship last year was pretty cool too.

Follow the Builder / Painter / Photographer / Race Series

• I can be found on Instagram here for more racing and bike stuff: @texaschrisjenner
• Your one stop shop for sweet paint jobs is @paintbymatt.
• And if you are interested in UK Flat Track racing and you’re not already following the DTRA (dirt track riders association) you should do here: @Dirttrackriders
• Photo Credits: Paint by Matt, Steven Haddock, and Braking Point Images