Practical Sportsbikes (UK)

SPECIALS WE LIKE

THREE BANGIN’ BUILDS from all around the globe

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Now expanded to three pages to celebrate the very best in global engineerin­g excellence

YAMAHA

XJ750R OU28

The past is a great source of inspiratio­n for specials, especially rare factory race bikes. This beauty is one of Yamaha’s earliest attempts at a Suzuka 8-Hour racer, which Shinichi Ueno and Hiroyuki Kawasaki took to fourth in the 1984 event.

Designated the OU28 it predates the FZ750 by a year and is powered by a highly-modified motor from the fairly unspectacu­lar (in road trim) XJ750 Seca, in a full prototype chassis.

You could use a FZ600 (or Japanese market FZ400) as a start point for a rep, given the similariti­es. But we know of a rep currently midbuild, with a custom frame to take an FJ1200 motor and modern running gear: see it in PS, soon.

ENGINE

The 749cc, air-cooled, dohc, 8v XJ750 motor made a modest 80bhp as standard; the OU28 kicks out 25 extra ponies – not huge peak power. Suzuka is an endurance race in a hot, humid climate –huge top-end numbers come with a reliabilit­y cost .

The extra horses were released thanks to extensive porting, high comp pistons, a lightened crank, factory pipe, Mikuni VM33S, and a race ignition. The stock XJ runs a five-speed shaft-drive set-up. The racer is six-speed with a chain drive conversion and a dry clutch. Trick.

FRAME

TT-F1 rules allowed prototype chassis; good job, as the road XJ’S tubular steel affair would no way have been up to the job. The OU28 uses a box-section aluminium cradle frame and underslung-braced swingarm working a rising-rate Monocross suspension. And even the ‘silencer’ bracket is weight-relieved.

WHEELS/FORKS

Period loveliness all the way, from the 18-inch Dymag front with H-section spokes, to the Campagnolo rear, plus those Gp-spec Brembo discs and calipers on YZR500 forks.

STAYING COOL

Preventing an air-cooled mill from cooking itself in a hostile climate isn’t easy, so the OU28 wears a massive oil-cooler (GSX-R size) and features huge scoops in the fairing to channel cool(ish) air to the cylinder head, giving the fairing a business-like look, much like Ted Lawson’s ’84 YZR500.

“YOU COULD SAY IT’S THE GREAT GRANDAD OF ROSSI’S M1. YOU CAN ALSO SEE WHERE THE FZ400 AND 600 GOT THEIR LINES FROM”

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 ??  ?? Is there ever a better look than an 8-Hour top fairing? We’d like to know
Is there ever a better look than an 8-Hour top fairing? We’d like to know

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