“Café racer on steroids” from Simon Kemper…
In 1978, Suzuki introduced their first-ever literbike, the GS1000, into a world of fearsome liter-size competition, including the new Yamaha XS11 and six-cylinder Honda CBX1000. While those bikes tended to edge out the Suzuki slightly at the drag strip, the tables turned when the roads got twisty.
“The Suzuki had a secret weapon – handling. While the Yamaha and Honda wallowed around like drunken hippos when ridden at speed, the GS1000 was rock steady.” –Classic Mechanics
The GS1000 would soon prove itself on racetracks across the world, where riders like Wes Cooley wrestled the brute to victory against fields of thundering air-cooled inline fours:
“The factory’s GS1000R XR69 track version successfully challenged Honda, especially in the contentious TT Formula races of 1980 and 1981, while in America Wes Cooley won the national Superbike series in 1979 and 1980 for Yoshimura Suzuki. Cooley also won the 1980 Suzuka 8-Hour race, partnered by Graeme Crosby…” –MCN
The GS also proven itself as a great platform for customization over the years, capable of handling heavy-duty modifications. That’s where our new friend Simon Kemper (@roid_rage_cafe) comes in, a London-based music producer who’s actually been building and rebuilding this same ’78 GS1000 for years:
“About three of this bike’s incarnations were done in a garage with a hole in the roof and a rusty bit of metal poking down in the doorway, which I hit my head on every single time I was working in there. My workbench was an old ironing board.”
Today, Simon works out of a purpose-built garage, and he started this latest build iteration during the depths of the pandemic, summer 2020. His vision for the old muscle bike was clear:
“I think of this bike as a café racer on steroids. All of the major custom parts are designed to be big, chunky, and slightly over-engineered looking. A bit like me.”
The engine is a 1216cc Mk1 Bandit unit that Simon rebuilt himself, complete with a flowed head, Wiseco 12:1 pistons, Kent cams, Mikuni RS38 flat-slide carbs, and more. The result is 150 rwhp at 9700 rpm — more than a 70% increase from the stock engine’s 87 whp!
Meanwhile, Simon worked with his long-time friend Lee Mitchell of Steelheart Engineering, who made the one-off box-section swingarm and subframe, an arsenal of CNC parts, and handled the extensive frame mods. In the rear, adjustable linkage lengths offer variable suspension rates from 1.9 to 2.1/1, dampened by a re-valved CBR600RR shock, while K9 GSX-R1000 forks with Öhlins cartridges handled suspension duties up front.
Nostalgia Motorcycle Upholstery handled the custom seat, while John at Boyz Toyz did the paint. We could go on and on with the modifications, but Simon offers a full build sheet in the interview below.
Simon appropriately nicknamed this incarnation of his overbuilt 150-whp café racer “Roid Rage.” It was one of our favorite builds from the recent Bike Shed Show in London, where our photographer Roberto Garagarza (@roga______/) got the show shots you see here. Below, we talk to Simon for the full story on the build.
Suzuki “GS1216” Café Racer: Builder Interview
Please tell us a bit about yourself, your history with motorcycles, and your workshop.
I split my working time between website tech and producing music for TV and online ads. I used to make music full time and had a deal with Ministry Of Sound and a few others.
As a kid I customised all my pushbikes and in my early teens i was building my own race bikes, including the wheel lacing, for track and time trials.
My first motorbike was a yellow Suzuki DR125 which was on its last legs, but I loved it. My second bike was a Suzuki GS1000; also on its last legs, but more about that later. I worked on the GS1000 in a spare bedroom including the respray. About three of this bike’s incarnations were done in a garage with a hole in the roof and a rusty bit of metal poking down in the doorway, which I hit my head on every single time I was working in there. My workbench was an old ironing board.
Now, I’m still working on the same bike but in a purpose-built garage.
What’s the make, model, and year of the donor bike?
Suzuki GS1000 1978.
Why was this bike built?
This latest build was started in August 2020 so was probably something to do with the lockdown.
What was the design concept and what influenced the build?
I think of this bike as a café racer on steroids. All of the major custom parts are designed to be big, chunky, and slightly over-engineered looking. A bit like me. The engine puts out good power too. I met Lee of Steelheart Engineering about 15 years ago when he made me a subframe for one of its previous incarnations.
On this new build, Lee made the swingarm, subframe, and the CNC parts along with the extensive frame mods. It was very enjoyable because Lee is very open to radical ideas, as well as having radical ideas of his own.
What custom work was done to the bike?
Mk1 Bandit 1200 just rebuilt by me.
Head flowed and barrels bored to 1216cc by Stan Stephens.
Wiseco 12:1 forged pistons balanced with pins.
Kent fast road cams with APE slotted sprockets timed to 104i/106e.
Mikuni RS38 flatslide carbs.
Mk2 sprocket/speed sensor, triggered by modified Kawasaki sprocket nut acting as trigger.
Heavy duty clutch springs.
Cases finished in Cerakote.
Mocal 19 row extra wide oil cooler.
Homemade pipework. Hindle 4.2.1 exhaust headers with custom link pipe and Austin Racing eccentric can to bring pipework closer to bike centre.
Extensive frame modifications.
Steel CNC heel plates to bring swingarm pivot into correct position for front sprocket and to provide mounting points for the two rear crossmembers.
One-off box section aluminium subframe.
One-off box section braced swingarm finished in clear Cerakote with linkages based on GSXR750 K6.
Adjustable linkage lengths and top shock mounting point to give variable suspension rate from 1.9 to 2.1/1.
CNC sprocket carrier to space chain towards 190 section tyre.
Too many one-off CNC parts to list, all hand finished satin and bright anodised.
GSXR 1000 K9 forks with Ohlins NIX 30 cartridges.
One-off yokes by Billet Bike Bits with inset clocks with extra breakout.
GSXR 1000 L1 wheels with Cerakote finish.
Top mounted adjustable steering damper.
Adjustable eccentric lock stops.
Ohlins rear shock from CBR600RR re-valved to my spec.
Brembo M4 radial front calipers.
Brembo P2 rear caliper.
Brembo RCS radial master cylinders.
Brembo Serie Oro discs.
Home made loom using a Motogadget M-unit blue and various other Motogadget parts. Motogadget switchgear.
Ignitech ignition module.
Purpose Built Moto headlight.
Motogadget Motoscope pro instruments.
Oil temperature sender in oil gallery.
Standard tank with Pingel tap.
Zedbutt seat unit.
Custom seat by Nostalgia Motorcycle Upholstery.
Paint by John at Boyz Toyz.
Done in a few stages while I took the bits away and put the pinstripes on.
Does the bike have a nickname?
I called it “Roid Rage” for the Bike Shed show!
Any idea of horsepower, weight, and/or performance numbers?
150rwhp @ 9700rpm
Weight: 175kg dry
Can you tell us what it’s like to ride this bike?
It’s an experience every time I ride it. The flat-slide carbs really make you work. It’s an effort to keep the throttle open, even on the lightest return spring setting. It’s pretty frantic, especially above 6k, and the handling is great since having the shock re-valved. I think I’ll probably do the same with the forks at some point.
Was there anything done during this build that you are particularly proud of?
This is the first time I’ve rebuilt this bike where I’m totally happy with everything. Having said that, I think the steel heel plates came out incredibly well and form an amazing functional and visually unique focal point of the bike. I wanted them to stand out against the light grey frame, so had them Cerakoted in clear.
I’m also pleased with the wiring loom. I learned how to use Adobe Illustrator to design it and went from there. I’ve wired a few music studios, so had a decent basic understanding. And the sprocket carrier, designed to re-mount part of a butchered Supersprox sprocket towards the centre of the bike, for chain alignment. And the top yoke with the recessed clocks… The swingarm is great too.
Is there anyone you’d like to thank?
Lee at Steelheart Engineering.