Yamaha TRX850
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| Manufacturer | Yamaha Motor Company |
|---|---|
| Also called | TRX |
| Parent company | Yamaha Corporation |
| Production | 1995 (Japan only) 1996–2000 |
| Class | Sport bike |
| Engine | 850 cc liquid-cooled 4-stroke 10-valve DOHC crossplane parallel-twin |
| Bore / stroke | 89.5 mm × 67.5 mm (3.52 in × 2.66 in) |
| Top speed | 135 mph (217 km/h) |
| Power | 59 kW (79 hp) (claimed) |
| Torque | 85 N·m (63 lb·ft) (claimed) |
| Transmission | 5-speed constant-mesh |
| Wheelbase | 1,435 mm (56.5 in) |
| Dimensions |
L: 2,070 mm (81 in) W: 700 mm (28 in) |
| Seat height | 795 mm (31.3 in) |
| Weight | 190 kg (418 lb) (dry) |
| Fuel capacity | 18 l (4.0 imp gal; 4.8 US gal) |
| Related | Yamaha TDM850 |
The Yamaha TRX850 is a sports motorcycle with a 10-valve DOHC 849 cc 270° parallel-twin engine. Yamaha first released it in Japan in 1995, and a version for the European market became available in 1996 to 2000.
The TRX has a half fairing, clip-on handlebars and mildly rear-set footrests. The front forks are conventional telescopics, and the rear suspension is a rising-rate monoshock unit. There is meagre provision to carry a passenger, and MCN declared: "comfort’s not brilliant for the pillion".
The TRX engine was derived from that in the Yamaha TDM850, but the TRX is lighter, lower and sportier than its TDM stablemate. The parallel twin engine has five valves per cylinder, three inlet and two exhaust. The engine produces some 85 Nm of torque and 79 bhp. Unusually for a dry sump design, the oil tank is not remote, but is integral to the engine, sitting atop the gearbox. This feature simplifies manufacture, eradicates external oil lines, and gives faster oil warm-up. The shallow sump allows the engine to be sited lower, for an optimal CG position. The 360° crank of the original TDM was changed to a 270° crank in 1996, after which time the TRX and the TDM shared the same engine and transmission. The engine has a balance shaft to smooth out vibrations.
While the 1995 version for the Japanese home market had Italian Brembo brake callipers, the European version had Yamaha callipers. In 2000 Yamaha stopped making the TRX, while the TDM series, enlarged to 900 cc, remained in production until 2011.
The TRX was designed to compete in the market with the Ducati 900SS V-twin, whose tubular trellis frame it mimicked. Although developed cheaply from Yamaha's "parts bin", using a TDM850 engine, the TRX performs well and has "a coherent identity of its own".
In Motorcycle News (MCN) the TRX was later described as "the best-kept secret in motorcycling" and a "forgotten gem" which bore comparison with the 270° Norton Commando 961. The MCN review states: "The TRX produces less power than sports 600s of the same era, but it’s much gruntier and more satisfying to use thanks to that twin cylinder character". The review added: "The TRX is a cracking bike, a sporty motorcycle with tons of character. It's stable, handles neutrally and feels like a proper sports bike". In 2014, Steve Cooper wrote of the TRX: "Very much the thinking man's sports bike, this slightly oddball twin is beginning to reach cult status and for good reason; with a little work it's possible to see a genuine 100bhp...".
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Wikipedia