Suzuki’s GSX-R750 is arguably the most influential sportbike of all time, and 2016 marks the 30th anniversary of when the original GSX-R750 debuted on American soil. The Gixxer 750 is now bookended by 600cc and 1000cc versions, but the 750 remains one of the best-balanced sportbikes on the market. Our Australian correspondent, Jeff Ware, has loads of experience with the GSX-R750, being a longtime motojourno and the restorer of the 1985 Gixxer used in the article below. Ware outlines the history of the GSX-R750 and compares his original GSX-R with its contemporary brother to illustrate the evolution of the sportbike over the past three decades. Enjoy! —Kevin Duke, Editor-in-Chief
The GSX-R750 sent shockwaves through the motorcycle world when it was unveiled in late 1984 at the Cologne Motorcycle Show in Germany. With a full fairing, aluminum racing frame, incredibly light weight and 100 hp, it was was a true racebike with lights. There is little argument against the general belief that the Suzuki GSX-R750F, the very first GSX-R750, was the first true four-stroke street superbike.
The bike was an instant game changer. I mean, show just about any red-blooded sportsbike enthusiast over the age of 35 a photo of a ‘Slabbie’ (nicknamed due to its slab-sided appearance) 750 and they will drool and then say, “I wanted one of those soooo bad when I was younger.” Or, “I had one of those; I wish I kept it…” The GSX-R750 had the same impact that the 1992 Honda Fireblade or 1998 Yamaha YZF-R1 had. Mind blowing. Nothing had ever looked so serious, being so light or so powerful and true to a racer replica.
It was faster, lighter and better looking than any motorcycle available. It also outperformed the two-strokes and came in at a competitive price. The same year, Yamaha released the FZ750 (700) and Kawasaki was still pushing the GPz900R. Honda had the VF750 (700) and VF1000. All of those bikes were brilliant in their own ways, but in terms of performance and weight, they were owned by the all-new ‘Light Is Right’ concept GSX-R750F. Stunning.
The brainchild of GSX-R Project Leader Etsuo Yokouchi, the GSX-R750 rewrote the sportbike rulebook. Yokouchi-san was a firm believer in pushing technology to improve the breed in an era when many Japanese engineers were being too conservative. He also loved racing and was the brains behind the Hans Muth-designed Katana. These two characteristics gave him the drive and direction he needed to produce a four-stroke supersport bike that could out-perform the two-strokes, which were getting increasingly difficult to market and get through strict global anti-pollution restrictions – America didn’t even get the RG500.
So, how did Yokouchi-san and team make the GSX-R so good? To understand that, we need to look at what was going on in Japan back then. Most big four-stroke superbikes at the time were simply beefed up versions of the Universal Japanese Motorcycle. They were heavy, poor handling but reliable and over-engineered. We were used to bikes like Suzuki’s own GS range, the Kawasaki Zeds, Honda CB900 and 1100s, and Yamaha XS11. These were big heavy bikes, with small brakes and low-rent suspension, packaged up in flexible steel frames and finished off with narrow tires. All of that was about to change.
At Yokouchi-san’s direction, the GSX-R was developed through experience racing the GS and GSX750R, with Kiwi Graeme Crosby and Len Willing (brother of famed GP tuner Warren Willing, who I did my mechanical apprenticeship with) riding the GSX750R in the Suzuka 8-Hour in 1984.
While the GSX-R was being developed, Suzuki released the RG250WE two-stroke and GSX-R400 four-stroke. Both gave the public and the other big three Japanese manufacturers a preview of things to come from Suzuki.
Yokouchi figured if the GSX-R400 could be made 18% lighter than its competitors then the scale could be applied to the GSX-R750. The horsepower limit at the time was already an agreed voluntary restriction of 100 hp, so he knew that light weight was the only way forward to higher performance. Before the project began, he had his engineers strip a GS750 and paint any parts that had not failed in the field blue and any that had failed red. When the parts were gathered together almost all of them were blue.
“We were too conservative,” he said. “Nothing ever broke. Everything was over-engineered.”
He set the target at 20% less than competitors’ 750s, the goal being 100 hp and 388 lbs.
Chassis development began alongside engine development. Yokouchi also insisted on using the racetrack dimensions. “What works on the racetrack will work on the street. The motorcycle does not know where it is being ridden,” he said. He started by using the 1983 Endurance World Championship-winning HB Suzuki GS1000R ridden by Herve Moineau and Richard Hubin as a base to build the GSX-R from. Styling was in the hands of the amazing Tetsumi Ishii, who took as many angles from the GS1000R as possible.
Since the release of the GSX-R750 in 1985, sportsbikes have gone full circle – lightweight, heavy, back to lightweight again, but one thing is certain: motorcycle performance can be split into two clear eras – the era before the GSX-R750F and the era after the GSX-R750F. Now 30 years on, and the GSX-R750F is still a stunning-looking machine. In fact, I rate it as one of the best-looking motorcycles ever released. I may be biased, as I own the example you see here, having bought it as a basket case and spending three years doing a full ground-up restoration to get it back to as new.
I ride the bike and I love it. It still holds its own, and having owned RZs, an FZ750 and ridden many GPzs and VFs, I can tell you none come close to the handling and performance of the GSX-R750F for the era. Put it this way, I have nine bikes, some modern, some older, and the GSX-R750 is the lightest bike in my garage. On the scales, it is 22 lbs lighter than the new GSX-R750!
Don’t get me wrong – things have come a long, long way in 30 years, and the old Slabbie would not even get close to catching the new 750 on the street or the track. But in terms of its era, the 1985 bike blew the others into the weeds. I was 10-years old then but still remember seeing them on the showroom floor of the Suzuki dealership up the street. I’d ride my BMX bike rain, hail, or shine to gaze at the bike through the window and dream of owning one – which is why I have one now, 30 years later.
The fact that the new engine is the exact same bore and stroke of 70mm x 48.7mm proves that Suzuki’s engineers got the motor right. Despite a swing to a short stroke 73mm x 44.7mm engine for 1988 and 1989, the factory reverted to the original dimensions in 1990, and it has remained that ever since. With modern cylinder-head technology, metallurgy, EFI, and electronics, it is now a whopping 50% more powerful.
1985 GSX-R750 Ride Impression
I’ve been restoring this actual bike for three years, and I’ve spent around $9,000 USD on parts and hundreds of hours in the shed. The bike has not turned a wheel for 20 years, and aside from running through the gears on a racestand, I have not tested it at all. To say I am nervously excited is an understatement – I’m as nervous as I was when I rode the priceless ex-John Kocinski Cagiva 500!
I’m very familiar with the current 750 and have spent a lot of miles scratching on them. I also owned a 2011 model 750 for a while. I have no huge expectations of the original bike, but I do have plenty to compare it to, as I recently rode most four-strokes from the same era. I also owned a 1985 FZ750 Yamaha, the main competition for the Suzuki back in the day. Just ask Wayne Rainey or Kevin Schwantz about their battles on those bikes.
I walk around my pride and joy and do a safety check. I try and put myself back 30 years, imagining what was going through journalists minds as they prepared to ride the bike for the first time at its world launch, held at Suzuki’s testing ground at Ryoyo. They must have been buzzing. I drool some more at the stunning racer replica looks and hop on the bike.
The old-school feel of the bike is brilliant. The huge screen sits tall and is so wide it is crazy. It must be three to four times the size of the modern version, which means it would be fantastic on the road. The way it curves around makes the bike feel racy. The tall and very narrow gas tank with endurance aircraft-style gas cap and vent is right under my chest, with a trick endurance style ventilation hose between my forearms, making me feel like Kevin Schwantz.
The ’bars are really wide apart. I love the way the top triple-clamp sits tall above the traditional clip-ons. A real race feel from the 1980s. My back is bent over and I’m almost in a race tuck. I’m sitting well inside the bike, not on the bike. The seat is plush and so low. The aluminum folding footpegs are hideously high and cramped feeling, while overall the bike is extremely narrow between the knees for an inline-Four, due to the main frame rails going over the top of the engine rather than around it like a modern frame does. The dash looks so basic but even for today it looks ready to race and has only the basics for performance. I love the foam-mounted clocks – that is pure 1980s and 1990s grand prix style. The other trick thing is the tacho doesn’t start counting until 3000 rpm, a subtle sign of the intentions of the GSX-R750.
The first thing I notice when I turn the key is … nothing! There is no fuel pump noise, there are no servomotors setting up, the dash doesn’t go through a series of epileptic fits. Nothing happens aside from the neutral light showing. It’s a reminder of the way things used to be in the 1980s.
I turn the fuel tap on, pull out the choke (when was the last time you did those two things?) and hit the starter button. The bike cranks hard a few times and after some spluttering and clunking it fires into life and rumbles away at a high idle, the smell of rich unburned fuel sticking to my leathers as it richly warms up on the choke.
Warming up seems to take forever, well it does, about five minutes before a clean idle, not like these days when bikes idle instantly and off you go, up the street before waking the neighborhood. I get it off the choke and give it some good throat-clearing revs. The heavy throttle and instant response a reminder that the bike has mechanical flat slides with accelerator pumps as standard.
I pull in the light-feeling hydraulic clutch lever select first gear, and then head out for my first-ever ride. It’s a moment I won’t forget in a hurry – it is everything and more than I imagined it would be, and I feel an incredible sense of achievement as I cruise out on a warm-up lap. After a few laps to scrub tires, bed the brake pads, make sure there are no fuel or oil leaks etc, I do a proper test and ride the bike as fast as I can, just the way it was meant to be ridden in 1985!
The immediate thing I notice is just how gloriously smooth the engine is. Suzuki nailed it from right back then, and it is silky smooth with a fabulous gearbox that puts a lot of modern gearboxes to shame, with a short, sharp and positive shift and minimal lever travel just like a well set-up racer. Upshifts and downshifts are slick, and the ratios are close, adding to the excitement of the ride. I can really feel why these bikes were so amazing for their time. The world’s top bike journos must have been absolutely blown away when they rode this machine for the first time.
The carburetion, although touchy because of the flatslides, is pretty good on my rejetted bike, and the engine loves to rev hard. So, I’m winding the throttle right to the stopper as the Gixxer screams to 10,500 rpm where it makes peak horsepower. Peak torque is also high in the rev range at 8000 rpm, making early throttle opening very easy and the bike tractable, just like the modern version. The howl from the standard exhaust system is invigorating, and the bike has the same spine-tingling sound as the new 750, without as much induction roar.
Acceleration is nowhere near the new bike. Top speed runs out at around 55 mph in first gear, 72 in second, 95 in third, and I just nudged 115 in fourth at the same spot the 2015 model was doing 132 mph. That’s a full 17 mph down on top speed with a similar run onto the actual back straight!
I have to admit I’ve had modern springs and emulators fitted to the forks, while the rear damper has been replaced by a modified R6 shock, so the suspension is much better than stock. Braking is similarly improved, with Venhill brake lines and Bendix brake pads. There is some improvement there over stock brakes, but nothing compared to the brakes on the new machine.
Cornering has to be done old-school style, with lots of braking a little early before fast sweeping lines through the turns. With the narrow tires (Pirelli Sport Demons) providing sensational cornering speed and the lightweight narrow rims helping with corner speed, the steering is faster than I thought it would be for big 18-inch wheels. However, in terms of being maneuverable or raceable, the new 750 would run rings around the ‘one-line’ GSX-R750F. I found tucking in low and not hanging off too much felt the most comfortable.
Overall, mind blowing for a 30-year old bike, but it needs to be ridden with finesse and patience, whereas the new bike can be ridden in anger.
Out on the street, my 1985 GSX-R is an incredibly good roadbike aside from the cramped footpeg position. Amazingly, it runs at a good temperature all the time. Yokouchi-san credits his grandmother for teaching him to stir his bathwater as inspiration for the Gixxer’s oil-cooling method. His old bath with a fire underneath had to have the water circulated to avoid hot spots, and he applied this principle by having the oil constantly flow around the GSX-R’s combustion chamber to keep it cool.
|1985 Suzuki GSX-R750|
2015 GSX-R750 Ride Impression
This bike looks great but somehow still has that GSX-R750 heritage we all love. The stacked headlights don’t do it for me, though, and never have on any bike, but I like the new 30th-anniversary bodywork and definitely the muffler. Oh how I would love one of these to partner my 1985 in the garage. With our fourth child due in April, I’ll be lucky to hang on to my ’85 let alone get a sibling! Maybe I’ll have to wait for the 60th Anniversary Edition!
Like I did with the old girl, I walk around the new 750 and take it all in. Minimal bodywork, a tiny screen, incredibly compact size compared to the 1985 bike and a huge meaty frame. The new bike first appeared in 2011 and has remained unchanged aside from cosmetic upgrades. When released it featured re-tuning for more mid-range over the 2009 model and it also came with Brembo brakes.
With no premier race class for 750cc motorcycles for well over a decade, many would assume that Suzuki development of the 750 was a by-product of the 600cc version, however, this is not the case. In fact, in staying loyal to the 750, the GSX-R600 is simply a smaller-capacity version of the 750 and the 750 is developed completely on its own merits so is not just a big-bore version of the 600, rather the other way around.
I like it, but as I walk around it I am not drooling like I do with the old bike. This is more from the fact that I was the kid looking through the shop window I mentioned than anything else … Sitting on the bike, the tank feels more comfy for my tall frame now, and there is an overall feeling that the bike is very low and narrow due to the flatter tank top and seat, plus the narrower seat rails.
Like all GSX-R750s right back to the 1985, the footpegs are high and uncomfortable. For me, they need to be on the lowest setting, but even then they feel too high. The ’bars are wide for a modern bike but narrower than the old bike and more steeply angled. I’m sitting much closer to the ’bars than on my 1985 model and on top of the bike, not in it.
The bike feels wider between the knees than the old one but so much lower around the tank and triple-clamp area. Seat height is taller and the seat firmer and wider, all up a seriously aggressive feel and make it hard to believe people said the 1985 bike was too aggressive in stance. Amazing how things change. The dash on the new bike is simple and compact but nowhere near as cool as the old-school clocks in the old girl.
Firing the bike up is easy, of course. No choke (no carburetors), no need to warm up for more than a few seconds, I simply hit the button and the engine settles to a nice idle in less than a minute. It has that traditional intake growl and sharp rumble from the muffler. Sounds much the same as the previous generations of GSX-R. They have all had that spine-tingling wail.
Heading out pit lane I short shift through the gearbox and the ratios feel closer than the old bike, and it revs so much faster. I instantly grin as the bike accelerates rapidly up the hill, making power at twice the speed of the original engine. But it’s when I get to the Turn-3 hairpin that I really feel a big difference. The initial bite of the Brembo brakes is insane compared to the 30-year old Tokicos, and the fork is so supportive while on the brakes. How do I ever complain about brakes and suspension these days? Turn-in response on the new bike is rapid and light, with the riding position making me feel comfortable, confident and in control from the off – something that was not the case on my old 1985 bike.
Once I warm up the tires, I put my head down and push the bike through my normal testing regime – one familiarization session, one session to push, and one to try and break the lap record! The acceleration is strong and I reach a top speed of 220 kph (136.7 mph) on the short back chute each lap in fourth gear. Braking hard from that speed to enter the uphill left at the bottom, the new bike feels great. There is not much stand-up on the brakes hard into the turn (lots of trail braking), and the steering remains light and accurate even under brakes. I can throw it around wherever I want to and fire it off the turn, unlike the original bike, which needs one classic line.
There’s a very neutral and controllable, almost effortless, transition from upright to full lean with no sudden fall-in, while the old bike flops on its side like it has a huge fuel tank high above the handlebars. Oh, wait a minute, it does … The new bike just rolls onto its side gracefully and holds a tight line with no unsettled behavior over any of the bumps. It’s hard to believe this is a 750.
Whether it’s accelerating through long turns, braking into hairpins, or changing direction fast, the GSX-R750 remains very responsive and easy to ride. Suzuki engineers have got the geometry very well sorted, and this is really highlighted by the performance of the suspension. The Big Piston Fork is fantastic, keeping the bike stable even under very hard braking, and off the brakes into a corner, it settled very quickly, going on to soak up any bumps and keep the front tire on the track at all times. The rear shock is not quite up to the same level as the forks, giving some rear-end instability and kicking back over some of the small bumps.
Overall, I was seriously impressed with the GSX-R750, but I love my old 1985 model. So, I think I need both!
|2015 Suzuki GSX-R750|
|1985 GSX-R750||2015 GSX-R750|
|Claimed power||75 kW (100 hp) @ 10,500 rpm||110.3 kW (146 hp) @ 13,200 rpm|
|Claimed torque||68 Nm (52 lb-ft) @ 8000 rpm||86.3 Nm (63.6 lb-ft) @ 11,200 rpm|
|Dry weight||176 kg (388 lb.)||190 kg (419 lb.)|
|Fuel capacity||18.5 L (4.9 gal.)||17 L (4.5 gal.)|
|Engine||Inline four-cylinder, four-stroke, oil-cooled, DOHC||Inline four-cylinder, four-stroke, liquid-cooled, DOHC|
|Bore x stroke||70.0 x 48.7mm||70 x 48.7mm|
|Fuel delivery & Ignition||VM29SS flat-sides, transistor ignition||SDTV 8-injector EFI with SDMS, new ECM and transistorised ICU|
|Exhaust||Four-into-one steel||Four-into-one stainless steel/Titanium Euro3|
|Gearbox||Six-speed close-ratio||Six-speed close-ratio cassette-style|
|Clutch||Wet, multiple-plate, hydraulic actuation||Wet, multiple-plate slipper|
|Final drive||530 O-ring chain||530 O-ring chain|
|Frame type||Aluminium cradle, alloy box-section swingarm||Twin-spar aluminium|
|Wheelbase||1425 mm (56.1 in.)||1390 mm (54.7 in.)|
|Trail||107 mm (4.2 in.)||97 mm (3.8 in.)|
|Front suspension||Posi Damp Fork, adjustable compression damping and spring preload, conventional 41mm, 130mm travel||Showa Big Piston Forks, four-way adjustable, 120mm travel|
|Rear suspension||Full Floater, rebound and spring preload adjustment, 127mm travel||Showa Link type four-way adjustable, 130mm travel|
|Front brake||Dual 300mm stainless-steel rotors, four-piston calipers||Dual 310mm floating stainless-steel rotors, Brembo four-piston 32mm radial-mount calipers, Nissin 17.46mm master-cylinder|
|Rear brake||Single 220mm stainless-steel rotor, two-piston caliper||Single 220mm stainless-steel rotor, Nissin single piston 30.23mm caliper, Nissin 14mm master-cylinder|
|Wheels||Cast aluminium, 18in||Cast aluminium, 17in|
|Tires||110/80-18 front, 140/70-18 rear||120/70-17 front, 180/55-17 rear|
|Ground clearance||140 mm (5.5 in.)||130 mm (5.1 in.)|
|Seat height||755 mm (29.7 in.)||810 mm (31.9 in.)|
|Overall height||1200 mm (47.2 in.)||1135 mm (44.7 in.)|
|Overall length||2130 mm (83.9 in.)||2030 mm (79.9 in.)|
|Instruments||Analog tacho and speedo, couple of idiot lights.||Analog tacho, digital speedo, dual trip meters, reserve trip, clock, coolant temp, oil pressure, lap timer, S–DMS indicator, gear position indicator, five stage shift light|
1985 GSX-R750 Tech Talk
While competitors moved to liquid-cooled engines, Etsuo Yokouchi headed the other way. He wanted lightweight and minimal complexity. Using the GS1000 engine and racing experience from the GSX750E, the GSX-R750 engine was designed.
The DOHC 16-valve inline-four-cylinder four-stroke featured a bore x stroke of 70.0 x 48.7mm, 9.8:1 compression, a wet multi-plate clutch and six-speed close-ratio gearbox. Liquid-cooling was ruled out as casting was not yet optimised, so the team used the same technique they had used on the XN85 Turbo: oil-cooling using jets to squirt oil onto the bottom of the large pistons. More oil than normal was also directed throughout the valve-train and upper cylinder-head and added extra oil capacity. Dual oil pumps move this oil swiftly around the engine and special channels help with fast flow. This was Suzuki’s new SACS (Suzuki Advanced Cooling System) and it allowed 100 hp with no overheating issues.
Every part of the GSX750E engine was redesigned. The pistons were 10% lighter, conrods 25% lighter, crankshaft 20% lighter, cylinder head 22% lighter, cylinder block 17% lighter, and gearbox and clutch also tested and redesigned to be much lighter than anything seen before.
Fueling was taken care of by competition-level VM29SS flat-slide carburetors, and ignition was by transistor type, which was standard for the day. The large airbox was under the false rear of the gas tank, and the exhaust system a lightweight four-into-one system.
The frame was cutting-edge for the day. A lightweight aluminum cradle frame with a cast alloy headstock and side swingarm pivot plates held a box-section alloy swingarm and cast aluminum triple-clamps. The forks were trick, with hydraulic anti-dive, Posi Damp, compression and preload adjustment and were a large 41mm diameter with 130mm of travel. The shock was a Full Floater unit with rebound and preload adjustment and 127mm of travel.
Another impressive feature on the 1985 GSX-R (for the day) was the brake system. Dual 300mm stainless steel rotors, Tokico four-piston calipers were strong and controlled with a Suzuki master-cylinder. The wheels were cast aluminium, both 18 inches, the front wearing a 110/80 tire and the rear a whopping 140/70.
The chassis team was led by Hiroshi Fujiwara and was based on the GSX-R400. Only five castings and 21 tubes make up the GSX-R frame, the structure said to weigh just 8kg. Styling was based as closely as possible to the XR41 racer, which is why the GSX-R has an unmistakeable racebike look. Wind-tunnel testing was a main focus, and the winglets and screen came directly from the factory racer.