Suzuki GSX-R 750L

In 1990 Suzuki brought a brand new bike. The new frame was once again wider and stiffer, the swingarm was both longer and thicker, the rear wheel was wider, as was the tire, the rear shock used an aluminum body and had a reservoir, and the front brake rotors were thicker and slotted versus the old model's drilled units, the rear wheel was an inch wider, with wider rubber, and then there was the engine.

For 1990, Suzuki went back to a long stroke design. This was mainly due to "issues" with the short strokers. One problem was the 1988/89 short stroke engines didn't have the low RPM torque of the previous generation Gixxers. To those who've looked at e ngine design, that's no revelation. What those short stroke street engines did have was great peak power. Unfortunately, the race versions didn't have as much power as the 1987 and earlier engines.

The solution was to design a long stroke engine that retained the short stroker's peak power and redline. That opened the door to a problem of piston speed. The long stroke and high redline brought the piston speed of the street bikes up to race bike le vels. To reduce bottom end stress, Suzuki lighten the rotating assembly. They used light weight pistons with a new coating called Alumite. They also used new rods and rod bolts. Ordinarily, rod bolts have nuts. For the new engine, Suzuki threaded the rod bolts into the rods themselves. This saved the weight associated with the nuts and washers.

Another problem with the 1988/89 engines was that they developed cracks between the sparkplug threads and the valve seats on the combustion chamber side (and Porsche owners thought they were the only ones with that problem). Suzuki addressed this by using smaller, 10 mm sparkplugs.

The old short stroke engines were fine for the street, but the racing versions ran hot. To ensure that didn't happen again, Suzuki used the GSX-R1100's larger, curved oil cooler. The curved oil cooler had the benefit of more surface area without requiri ng a wider space to mount it. Suzuki reported the new oil cooler was 48% more effective. To address the oil windage issues usually associated with the higher crank speeds, Suzuki used a deeper oil sump.

Outside of California, the new bikes got larger carbs. The new units were 38 mm. In California, the smog police determined 36's were big enough. In the U.S, the new carbs came with a blank power jet. Suzuki disabled the system by installing a blank, or zero ('0') jet. I'm not sure why Suzuki did this. Maybe they knew a good percentage of GSXR owners tossed their airboxes in favor of individual air filters. Those who kept their airboxes simply had their favorite tuner jets install a power jet and change the main jet circuit. The issue of ground clearance was addressed with a new four-into-one exhaust.

The results were spectacular. In addition to handling and braking better than the previous model, the 1990 GSX-R750 was a 10 second quarter mile bike.

Source marcusfitzhugh.com

The L-model was the first production bike in Britain with upside-down forks. It also had the other crucial requirement of the time - a riding position worthy of religious torture.

With your arse in the clouds, feet not far behind and hands a few inches from the front wheel spindle it takes only ten minutes in traffic to wish you'd bought a Honda CBR600. Back, wrists and neck take the worst of it but knees and shoulders follow. In twisties it's perfect, letting you climb all over the bike, but leathers without stretch panels will give your elbows and knees love bites.

Getting off the Suzuki onto the ZXR was like climbing aboard a Honda Gold Wing. Seriously, it's that bad. Half the time I hated it-the engine's rough, the mirrors are useless - but when it all comes together in a flurry of high-revving, adrenalin-fuelled madness I'd forgive this bike anything. It's brilliant.

The engine is still great for all its air-cooled antiquity. Maybe a bit feeble for a 750 until you hit six grand and then it takes off on a mad dash for the redline. The smooth clutch and gearbox keep things on the boil and you have to thrash it everywhere. It's the perfect bike for anyone wanting to meet policemen.

With such a speedy character it's fortunate that the GSX-R handles well. The cradle frame Suzuki persisted with for so long makes the bike tall and the handling challenging, but the Suzuki still devours corners once you're used to it. The steering is very slow initially and you've got to be up for a fight. "It takes a good shove on the bars and much shifting of body weight," said Adrian, "but once you've shown who's boss, the Suzuki rolls over and holds a line perfectly."

Unusually, the suspension still worked after eight years of abuse. GSX-R suspension has always been good, nicely damped with a luxurious ride quality. This one had a different rear spring fitted and some of the adjusters were seized, but it worked well enough not to need fiddling with. There's more ground clearance than most riders will ever need and with Pirelli Dragons fitted you can use it all.

"It works better if you're aggressive and feels better too," said ex-GSX-R owner Tom. "There's a sense of achievement cornering hard on one of these, not because the bike's rubbish but because it's a rider's bike. You put more effort in and get more out." More out of pocket too. At around 33mpg with some of the silliest spares prices around, a GSX-R can be expensive to live with.

There are a lot of secondhand imports around, most of which are low mileage and clean, but prices are up a few hundred quid on a UK bike and perilously close to that of a two-year-old GSX-R750. It's a good bike next to the new lad, there's no contest.

 The GSX-R750L was possibly the best of the oil-cooled models. Big changes included inverted forks and, importantly, a return to the long-stroke motor (the short-stroke wasn't so good in race-trim but was OK for the road). Other modifications included a 4-1 exhaust, steering damper, 38 mm carbs (up 2 mm on the standard K yet 2 mm smaller than the RK), smaller valves, new conrods, lighter pistons, large capacity oil pump, larger curved oil cooler and the rear rim became the 'standard' 17" x 5.5" item. Power was up to 115 hp at 11,000 rpm while weight was down to 193 kg. 

Drawing on the invaluable experiences gained racing, the 1990 model received many of the features of the race version GSX-R750R at an affordable price.

The same long-stroke engine (70 x 48.7mm) of the 'Double R' became standard, with new pistons to match the new combustion chamber design in the cylinder head and strengthened connecting rods. New 38mm Slingshot carburetor, Curved-core Radial Flow oil cooler and stainless steel 4-into-2-into-1 exhaust per set were adopted. Both 41mm inverted tube front fork and remote reservoir rear shock became fully adjustable. Rear wheel rim was widened and equipped with Michelin radial tyres.