YAMAHA YZF 750 R (93)

Press picture of the '93 YZF750R

The girly-coloured successor to the impressive OW01 legacy. Unfortunately launched in the shadow of the Fireblade bombshell of 1992, the YZF was built for two reasons - that's one more than its Blade-shaped rival. The common cause was that of shifting units and making money, but whereas the CBR900 was happy at that, the YZF stuck to the 750-limit in order to win races and therefore be more successful at point number one again.

And that's where it ran up against Kawasaki's impressive ZXR750L1. But with a 20-valve short-stroke motor, and EXUP blessed midrange poke to boot, the YZF was the class-leading 750 the minute it was launched. It made 106bhp at 11 750rpm too, which made it the highest revving bike in its category, despite a healthy midrange.

With the sharpest geometry possible, the first reports reckoned that the YZF steered like a 400, but went like its five-geared big brother, the FZR1000. Then they remembered the Fireblade again, and went off to drink pints and smoke tabs. Which was most unfair, because the YZF was a properly specced-up stoater of a race-replica.

Six-pot brakes were attached to the 41mm usd forks, which in turn hung off a rather lovely Deltabox aluminium alloy frame. With a braced-to-the-hilt swinger and single-seat cover, image should never have been an issue. Whitham's Fast Orange YZF was a real hum-dinger too, dominating the 1993 season with its unhealthy pace and talented rider.

Of course, this machine was based on the homologation-special YZF750SP. Hitting us for 3000 more than the standard "R", the SP was just the first part of a proper racebike. That extra cash got you compression damping adjusters both front and rear, a genuine single seat unit with lighter sub-frame, and those lovely pink graphics. Still.

As well as that, you'd find some nice 39mm flat-slide carbs with electronically controlled accelerator pumps to stop you starving the engine of fuel with cack-handed technique. It also got peakier cams and ever-so-different valve gear. First gear took you to over 85mph, with the other five slotting home in a close-ratio pattern. Quite whether a bumpier and more unfriendly ride was worth spending 9999 for instead of 6999, for general use, is beyond me. The only people that might have possibly thought so were the pukka race teams with access to the factory race kit.

Speaking of which, Yamaha never did find its stride in WSB with the YZF's. Fair enough, under Whitham and MacKenzie they got plenty of BSB podiums, but it was only Haga who ever found the pace on the world stage. And that was two years after the bloody things had dropped out of production anyway.

In fact, thanks to Yamaha's crap timing, the YZF was only in production for three short and unsuccessful years. by 1996 it was all over, and it wouldn't be until the OW02 R7 was released that Yamaha would enter the 750 market again. Instead the firm concentrated on producing the R1

Yamaha's YZF superbike reached the shores of Britain late on in 1992 and immediately became a big seller in early 1993. Sales were also boosted when the "Yamaha Fast Orange" team took the honours in the domestic Superbike series. This was Yamaha's first real update to the 750 class in almost a decade, (the OW01 was really just marketed for the racing teams benefit when it did appear), after having concentrated on the 600 and 1000 classes to bring the FZR 600 and FZR 1000 EXUP up to date with the competition.

The engine was billed as "A substantially up-rated version of the OW01 power-plant, the 20-valve YZF engine features a high compression head, straighter and narrower inlet tracts, bigger bore carburetors and a larger capacity air box." The biggest difference between this and the original FZ 750 motor, was the fact that it was now fitted with the Exup control system. EXUP, (Exhaust Ultimate Power valve), works by constantly adjusting the internal diameter of the exhaust system to perfectly suit engine revs. This ensures massive low to mid-range performance for a linear power output all the way to the rev limiter.

The chassis was another huge difference over the FZ 750, but not to much removed from the OW01. It features the light, compact and remarkably strong, short wheelbase aluminium Delta-box frame, using the forward sloping engine as a stressed member to optimise rigidity. This was advertised as being exactly the same as those used by the factory World Superbike teams. The suspension was also given a revamp and now featured USD forks with a rear shock adjustable for preload and rebound damping. Along side the USD forks were the awesome 6 pot brake calipers, the first production motorcycle to feature them.

YZF750R TECHNICAL SPECIFICATIONS

ENGINE

 

Type

4-stroke, liquid-cooled, DOHC, 5-valve, Parallel four cylinder

Displacement

749.0 cc

Bore and stroke

72.0 x 46.0 mm

Compression ratio

11.5 : 1
Max. power (DIN) 125 PS, (92 kW)@ 12,000 rpm
Max. power (ISO) 119 PS, (87.5 kW)~ 12,000 rpm

Max. torque

8.2 kg-m, (80.4 Nm)@ 9,500 rpm

Max. torque

8.2 kg-m, (80.4 Nm)@ 9,500 rpm

Lubrication

Wet sump

Carburation

BDST38 x 4

Ignition

Transistorised

Starter System

Electric

Fuel tank capacity

19.0 litres

Oil tank capacity

4.0 litres

Transmission

6-speed

Final transmission

Chain

CHASSIS

 

Overall length

2,065 mm

Overall width

730 mm

Overall height

l,l65 mm

Seat height

795 mm

Wheelbase

1,420 mm

Min. ground clearance

130 mm

Dry weight

195 kg

Front suspension

Telescopic forks

Rear suspension

Swinging arm

Front brake

Dual 320 mm O discs

Rear brake

Single 245 mm O disc

Front tyre

120/70-ZR17

Rear tyre

180/55-ZR17

Below is a picture of my `93 model YZF, shortly before I traded it in for the `95 model, which can be seen in "crashers corner".

My '93 YZF just before it was traded for the '95 version

And the modifications I made to the bike were as follows.

1.Muller carbon fibre race can.
2.Dynojet stage 1 carburetor  kit.
3.K & N air filter kit.
4."SP" Ohlins rear shock fitted.
5.Extra 20mls fork oil, & yokes dropped by 10mm.
6.Braided steel brake lines & SBS pads, with Motul dot 5 fluid.

While the engine modifications didn't give me a great increase in peak power, (106 to116 Bhp measured), it did give a huge increase in power throughout the mid-range. Typically around a 25 to 30Bhp increase. This also improved throttle response throughout the full range.

The modifications to the chassis did make a huge difference. The rear unit was now adjustable for compression as well as rebound and preload, but could have benefited if it had a greater range, particularly on the soft end of the range. The front however was not so adjustable, only preload, but increasing the amount of fluid in the legs, together with backing the preload off, I was able to get a good compromise, and by dropping the yolks just 10mm, it made a dramatic difference to its turn in speed.

The brakes were all ready state of the art stuff, but my own personal preference for the braided steel lines prevailed. The YZF did have one Achilles heel and these were the front brake discs. They had a habit of warping through serious use, but once the pads had been replaced with the SBS types, friendlier friction material, there was never any further braking problems.

Unfortunately I never recorded any other details about the modifications carried out, so that's it I'm afraid. Don't hesitate to E-mail me if you want any further information, or if you need any parts as I still have a garage full of spares.

Here are some action pictures from Knockhill Race Circuit, in Scotland and some wanton damage to the ozone in Wellbank.

Starting a dohnut on the YZF Half way there! Stopping traffic in it's tracks....!

Going round Macintyres at Knockhill Dropping off the end of Duffus Dip at Knockhill Going in deep into Clarkes Curve at Knockhill Close up through Macintyres at Knockhill

Getting the rear rolling...... 4th gear and rolling.... Ooooops! almost cut out there......!

For a bigger image size, just click the thumbnail you want.

All the central photos taken at the Performance Bikes Track day in August 1993, the rest taken by G. Paterson at Wellbank in April 1994.


Last updated June, 2004
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