Yamaha TZR250RS

Yamaha TZR250RS
Manufacturer	Yamaha
Production	1993
Engine	Two stroke, 90° V-Twin cylinder, read valve induction
Compression ratio	7.5:1
Top Speed	112 mph / 180.2 km/h
Ignition	Microcomputer controlled
Transmission	6 Speed
Suspension	Front: 39mm Upside-down forks Rear: Monocross linkage
Brakes	Front: 2X disc 4 piston calipers Rear: Single disc 2 piston caliper
Front Tire	110/70 Z17
Rear Tire	150/60 Z17
Wheelbase	1340 mm / 52.8 in
Seat Height	780 mm / 30.7 in
Weight	126 kg / 277.8 lbs (dry),
Recommended Oil	Yamalube 10w-40
Fuel Capacity	15 Liters / 4.0 gal
Manuals	Service Manual

It could reach a top speed of 112 mph / 180.2 km/h.

Engine

The engine was a Liquid cooled cooled Two stroke, 90° V-Twin cylinder, read valve induction. The engine featured a 7.5:1 compression ratio.

Chassis

It came with a 110/70 Z17 front tire and a 150/60 Z17 rear tire. Stopping was achieved via 2X disc 4 piston calipers in the front and a Single disc 2 piston caliper in the rear. The front suspension was a 39mm Upside-down forks while the rear was equipped with a Monocross linkage. The TZR250RS was fitted with a 15 Liters / 4.0 gal fuel tank. The bike weighed just 126 kg / 277.8 lbs. The wheelbase was 1340 mm / 52.8 in long.

Photos

Overview

Yamaha TZR 250RS

Visually, the TZR is a spitting image of John Kocinski's 1990 world-championship-winning works Yamaha YZR250, save for its lights, turnsignals, passenger perch and lack of sponsorship decals. In actual ancestry, the TZR is a close relative of Yamaha's TZ250D production racer, the two sharing the same crankcases, bore and stroke, displacement and 12,000-rpm redline. As on the TZ, the TZR is powered by a counterbalanced, two-stroke V-Twin with a bore and stroke of 56.0 x 50.7mm for a displacement of 249cc. TZ-style reed valves and a six-speed, cassette-type transmission add to the list of road-race-quality components. Bloom provided us with a 1991 TZR to sample at Laguna Seca Raceway. Unfortunately, the only one he had available at the time was a Japanese-spec model limited by that country's strict home-market regulations to a claimed 45 horsepower-about one-third less than on non-restricted versions. But despite its reduced power output, it still impressed us with its overall performance. For one thing, the engine possesses a surprisingly wide powerband, attributable to its computer-controlled engine-management system. An eight-bit microcomputer controls the advance curve of the electronic ignition, the actuation of the exhaust pow-ervalve, and the fuel mixture provided by the flat-slide 26mm Mikunis. All of this allows the little 250 to pull cleanly and steadily from low rpm, but the real but the real

excitement is found on the upper floors of the rpm scale. Kept zinging between 8000 and 11,000 rpm, the engine is surprisingly potent and exciting, even if it does fall far short of the championship-caliber performance of the YZR250 roadracer, which pumps out nearly twice the power of the TZR. Though unable to measure top speed, we saw an indicated 155 kph (about 96 mph) over the crest of Laguna's Turn One. But those who lust after 250 race replicas don't expect Superbike-level engine performance. They place greater value on lightning-quick handling, which is the TZR's greatest virtue. The bike's aluminum, twin-beam Deltabox frame, allied with ultra-responsive steering geometry (24 degrees of rake, 3.5 inches of trail) and a 278-pound claimed dry weight, allowed the TZR to be flicked through Laguna's infamous Corkscrew with almost ridiculous ease. But that agility also has its drawbacks, as the TZR's responsive nature requires an equally light touch at the controls. Ham-fisted riders need not apply. Braking is outstanding. The TZR's 39mm inverted fork is fitted with four-piston calipers pinching a pair of floating discs. Even under repeated abuse around Laguna's 11-turn circuit, the brakes consistently provided excellent feel and were resistant to fade. Though our riding time on the Yamaha was limited, both fellow Associate Editor Don Canet and 1 came away with a strong appreciation for the TZR's phenomenal handling. No, the TZR250R will not break any speed records or set blazing quarter-mile times; but when it comes down to consuming corners, nothing currently in any manufacturer's U.S. lineup even comes close. Matthew Miles 1992

Make Model	Yamaha TZR 250RS
Year	1993
Engine Type	Two stroke, 90° V-Twin cylinder, read valve induction
Displacement	249.7 cc / 15.2 cu-in
Bore X Stroke	56 x 50.7 mm
Cooling System	Liquid cooled
Compression	7.5:1
Induction	2x Mikuni flatside carburetor
Ignition	Microcomputer controlled
Starting	Kick
Max Power	45 hp / 33.6 kW @ 9500 rpm
Max Torque	3.8 kgf-m / 40 Nm @ 8000 rpm
Transmission	6 Speed
Final Drive	Chain
Front Suspension	39mm Upside-down forks
Rear Suspension	Monocross linkage
Front Brakes	2X disc 4 piston calipers
Rear Brakes	Single disc 2 piston caliper
Front Tire	110/70 Z17
Rear Tire	150/60 Z17
Dimensions	Length 1960 mm / 77.1in Width 680 mm / 26.7 in Height 1075 mm / 42.3 in
Wheelbase	1340 mm / 52.8 in
Seat Height	780 mm / 30.7 in
Dry Weight	126 kg / 277.8 lbs
Fuel Capacity	15 Liters / 4.0 gal
Top Speed	112 mph / 180.2 km/h