Yamaha TRX 850

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Yamaha TRX

The TRX 850 (internal model name "4UN") is a motorcycle model from the Japanese motorcycle manufacturer Yamaha .

Model characteristics

It was built between 1995 and 1999. The 1995 model year was only available on the Japanese market and differs from the following year of construction in that it has a different braking system and a different engine configuration (with slightly less power). The TRX 850 was built almost unchanged between 1996 and 1999. The only known changes (in addition to different color variants) were the use of harder valves from model year 1997 and a shorter gear ratio in first gear for model year 1999.

The TRX 850 has a parallel twin with a displacement of 850 cm³ and a tubular space frame. The basis of the TRX engine is related to the engine of the Yamaha TDM 850 (version 4TX). With its hand-welded tubular space frame and an unusual crank pin offset of 270 degrees, which is responsible for an Italian exhaust blow, the TRX 850 was clearly positioned against the Ducati 900 SS .

The machine is sometimes called "Trixxe" or "Trixie" by drivers.

Soon after the Yamaha TRX went on sale, the Honda VTR 1000 (Firestorm) and the Suzuki TL 1000 were presented to the public as representatives of a new performance class of powerful Japanese two-cylinder engines. These two models offered significantly more performance.

Technical specifications

Engine: Two-cylinder inline, four-stroke, liquid-cooled, DOHC , two balance shafts , dry sump lubrication
Valves: 5 valves per cylinder operated by bucket tappets
Compression: 10.5: 1
Bore × stroke: 89.5 x 67.5 mm
Crank pin offset: 270 degrees
Displacement: 849 cc
Power: 83 hp (61 kW) at 7500 rpm
Torque: 87 Nm at 6000 min-1
Fuel: Regular unleaded gasoline
Consumption: 5.2-7.5 l / 100 km
Carburetor: CV carburettor Mikuni BDST38 / 2, downdraft arrangement
Ignition: contactless transistor ignition
Coupling type: multi-disc oil bath clutch operated by Bowden cable
Transmission: Claw-shifted five-speed gearbox (I: 36/14, II: 37/20, III: 30/21, IV: 27/23, V: 28/27)
Primary drive: Spur gears (67/39)
Secondary drive: O-ring chain to the rear wheel (39/17)
Landing gear: Tubular steel lattice frame, telescopic fork with spring base and rebound damping adjustable with 41 mm standpipe diameter and 120 mm spring travel, rear two-arm swing arm made of aluminum profiles, central spring strut with 128 mm spring travel articulated via a lever system, adjustable in rebound and compression damping
Wheelbase: 1435 mm
Seat height: 795 mm
Steering head angle: 25 °
Trailing: 97 mm
Brakes: Front 270 mm double disc brake with four-piston fixed calipers and floating discs, rear single-disc brake with two-piston fixed caliper
Wheels / tires: Three-spoke cast aluminum wheels, front 3.50 × 17, rear 5.00 × 17 / front 120/60 ZR 17, rear 160/60 ZR 17
Electrics: 12 V, three-phase alternator 700 W, battery 9 Ah Yuasa YTX9-BS
Spark plugs: NGK DPR8EA-9 or NipponDenso X24EPR-U9 (electrode gap: 0.8 - 0.9 mm)
Tank capacity (reserve): 18 L (3.5L)
Dry weight: 188 kg
Vehicle weight (ready to drive, fully fueled): 213 kg

Web links

Commons : Yamaha TRX  - collection of pictures, videos and audio files

supertwin850.de (The German forum about the TRX 850)