100,000 miles on a GS1000S Katana: “She’s family, that makes her priceless…”
In 1982, a 1000cc version of the Suzuki Katana 1100 was introduced to qualify for AMA Superbike racing. The bore was sleeved down 2.6mm to make the engine 998cc, and the bike was sold in the US as the GS1000S Katana. The Twin Swirl Combustion Chambers (TSCC) had been reshaped for better high-rpm fuel atomization, making the performance nearly equivalent to that of the larger engine.
There was nothing else like the Katana when it appeared, looking like a two-wheeled version of its razor-honed namesake, and the riding experience similarly sharp:
“Clip-on bars and rear-set pegs and controls made the Katana feel like a much more focused beast than its GS1100 brother. Named after a samurai sword, the Katana was meant to be a purposeful tool.” –Motorcycle Classics
Our new friend Thomas Miller of Southern California caught the two-wheeled bug at a young age, starting off in trials — a discipline he still pursues at 61, riding his Montesa 4RT. As a teenager, he found his way to street bikes during the heady era of the big-bore superbikes.
“At 15, I dove head first into those and the Superbike era of the seventies and eighties. Taught myself welding, machinist, and metal fabrication skills as I modified any bike I could lay hands on. Put a KZ1000 motor in my Honda CB650. A tire smoking wheelie machine.”
Later, he opened a small home shop where he did motorcycle maintenance work while his kids grew up, working on everything from the neighbor’s PW50 to the Ducati 998 SPS of a wealthy rider. The Katana remained a dream bike of his, and he picked up this ’82 GS1000S for $1000 after it had been laid down at Willow Springs Raceway in the early 90s.
He quickly realized the “blown motor” was nothing but a wire-retaining tab rubbing the flywheel, but his work was just beginning:
“First ride up Mt. Baldy road told me this thing didn’t like to turn. That was the catalyst for my project. I purchased 1989 GSX-R1100 parts and started stripping the Katana down.”
The build has evolved countless times over the decades, but the main modifications include a braced frame, GSX-R1100 wheels / suspension / swingarm, rear mono shock conversion with a Fox GSX-R750 “twin clicker” shock, Tokico six-piston calibers with Discacciati floating discs, original engine with ported head and degreed cams, Keihin smoothbore carbs and Yoshimura 4:1 exhaust, 14-row oil cooler, spin-on oil filter conversion, bespoke rear-set controls…the list goes on.
While some of the restomod superbikes we feature read like little more than a bank-draining assemblage of brand name parts, Thomas’s Katana is a work of home-brewed engineering, iteration, and experimentation.
“Since the original build, there have been many little refinements done. I’ve never had the spare cash for Ohlins, Dymag, Brembo, etc., but I’ve always had the desire to build and make things perform better. I like to build, not just swap parts.”
While Thomas has ridden many of the faster modern bikes, nothing quite compares to the sensations of this air/oil-cooled legend — no wonder he’s put more than 100,000 miles on the bike in his 34 years of ownership:
“The Kat is a blast to ride, not just because of the attention it attracts…but the ‘old school’ acceleration. It’s not as fast as modern machines, but you can feel the motor under acceleration straining at the chassis as if looking for the opportunity to break free.”
Best of all, this Katana has become a real part of the family over the years.
“She was my dream bike, my date bike, in my marriage procession, two-up knee dragging with my wife, road trips, taking my kids for rides, teaching them to ride her, track time. She’s still just as fun now as when I first got her. She’s a Katana, that makes her special. She’s family, that makes her priceless.”
Well said, Thomas, very well said. Machines like these are the true legends — real riders that become deeply entwined with the owner’s blood and guts, family and history. Thomas, good on you for keeping this dream on the road and track, in the canyons and in the family. We’re honored to feature it, and we hope you check back in with us once you finish that 1260cc engine for it — we’d love an update!
Katana GS1000S Restomod: Builder Interview
• Please tell us a bit about yourself, your history with motorcycles, and your work space/shop/shed.
I’m 61 years old, born in the Pacific Northwest, lived a very active life with 8 brothers and 2 sisters. I was always interested in things mechanical. I’d modify my bicycles to try to make them better, stick playing cards in the spokes to simulate a motor, etc. I finally got on motorcycles at about 12 years old. I’d take apart carburetors just to see how they worked.
We had by that time migrated to Southern California in the Mojave Desert. I was introduced to Motorcycle Trials about that time with a Honda TL125, which I modified to make it lighter and quicker. Ended up in the Inland Empire of the Los Angeles basin where the only motorcycles I could get on were street machines. At 15, I dove head first into those and the Superbike era of the seventies and eighties. Taught myself welding, machinist, and metal fabrication skills as I modified any bike I could lay hands on. Put a KZ1000 motor in my Honda CB650. A tire smoking wheelie machine.
I got married at 30 to a beauty from Brazil, moved back to the high desert, was able to work for a few years at a small motorcycle shop in Phelan, CA. I then opened a small shop on my property and did motorcycle maintenance work for about 15 years so that I could be with my kids as they grew up. I worked on everything from the PW50 for the little kid down the block to the Ducati 998 SPS of a wealthy businessman.
My shop is small, 16×16 feet. Pretty cramped with a milling machine, lathe, welders, surface grinder, and all the tools that go with it. But I’ve been able to build motors, port heads, modify chassis and suspension systems. And dream about the “big build”. The 1260 motor I’m currently building for the Kat. It should be fun!
• What’s the make, model, and year of the donor bike?
1982 GS1000s Katana; Original Build: 1992.
• Please tell us about your Katana.
I found this “bike of my dreams” out behind a garage in Riverside, CA. It had been laid down at Willow Springs Raceway in Rosamond, CA, suffering minor damage. Broken left engine cover, bent clip-on, dent in tank. It was advertised for $1000.00 with the replacement engine cover and clip on! And a blown motor. 18,000 miles. They were hard to find even back then — I grabbed it. The “blown motor” turned out to be a wiring retaining tab rubbing the flywheel making a noise like a bad bearing.
First ride up Mt. Baldy road told me this thing didn’t like to turn. That was the catalyst for my project. I purchased 1989 GSX-R1100 parts and started stripping the Katana down.
The front end was pretty straightforward. I made a new steering stem, modified the turning stops, shaved the inside of the fairing for the wider fork tubes. I used the 1100 tubes, and 750 lower fork legs so that I had the length I needed, and full adjustability.
Rear suspension was more involved since I was making it a mono shock. I had to shave the inside of the frame swingarm pivot points to accept the wider GSX-R swingarm. Machined an upper shock mount and welded in mount points on the frame and braced the area.
The lower mount was an experiment. Initially, with the lower mount in place, when I put the bike’s weight on the suspension, it just sagged. I moved the lower mount incrementally until the suspension “sat” where I wanted it to. Eyeball engineering I know, but it handles great!
I shaved off the old shock mounts and tucked the subframe up, trying to get that clean “see through superbike” look.
Built an offset countershaft sprocket and machined the rear wheel cush drive hub to move the rear sprocket in to obtain correct chain alignment. Also converted to a 530 O-ring chain.
Custom fabricated rear set foot controls. Battery and electrical were all repositioned. Grafted in GSXR switch gear and instruments (soon to be KOSO RX-2 unit).
Since the original build, there have been many little refinements done. I’ve never had the spare cash for Ohlins, Dymag, Brembo, etc., but I’ve always had the desire to build and make things perform better. I like to build, not just swap parts. From my first TL125 to my current KZ1000 motor shoehorned into a KZ650 chassis on GPz Suspension.
If this Kat was “experimental,” I suppose it’s a success. I have logged over 100,000 mostly canyon and race track miles in the 34 years I’ve had her. I’ve ridden a lot of new bikes over the years, but none grab my heart like my Kat. She was my dream bike, my date bike, in my marriage procession, two-up knee dragging with my wife, road trips, taking my kids for rides, teaching them to ride her, track time. She’s still just as fun now as when I first got her. She’s a Katana, that makes her special. She’s family, that makes her priceless.
• Can you tell us what the riding experience is like on your Kat?
The Kat is a blast to ride, not just because of the attention it attracts, there is nothing else like it. But the “old school” acceleration. It’s not as fast as modern machines, but you can feel the motor under acceleration straining at the chassis as if looking for the opportunity to break free. The modded chassis handles it well, rock-solid stable, even at high speeds. No twitchiness with much quicker initial response to rider inputs.
It is a bike you ride more physically, but it doesn’t throw any surprises. Acceleration is much improved over stock, and doesn’t take much to lift the front end just for fun. And with the upgraded front brakes, it is very common to feel the rear wheel lift off when braking hard into a turn. A big difference over stock.
• Is there anyone you’d like to thank?
I’d like to thank my wife for encouraging me to “keep the dream.” And also, to go ride my Montesa 4RT sometimes and forget about work for a bit.
Full Build Sheet
Chassis:
- 17-inch wheels and suspension (1989 GSX-R1100).
- Tokico six-piston brake calipers.
- Discacciati Floating Brake Rotors.
- Fox “Twin clicker” mono shock (GSX-R750).
- Frame braced, upper and lower mono shock mounts added.
- Subframe modified.
- Custom foot controls on bronze pivot bushings, with ball bearing linkages.
Engine:
- 1982 GS1000 motor, ported head, stock camshafts degreed.
- GS750 oil pump gears.
- APE clutch pack.
- Manual camchain tensioner.
- Earls 14 row oil cooler.
- Spin-on oil filter conversion.
- Dyna S ignition, Dyna coils.
- Keihin 33 mm smoothbore carburetors, K&N pod filters.
- Pingel, dual feed petcock.
- Clutch cover, sprocket cover from Ballistic Performance in Australia.
- GSX-R1100 Yoshimura 4 into 1 exhaust. Modified to fit.
- JW Speaker Headlight.
- Seat cover by Raul’s Auto Trim in Ontario, CA.
Paint:
Gloss Black with Violet Pearl clear coat, and lightning graphics by PMT Design in Redlands, CA.
