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Yamaha SZR660

Manufacturer	Yamaha
Production	1996-2001
Class	Sport bike
Engine	659 cc, 4-stroke, SOHC, liquid cooled, 5 valves, single cylinder
Power	48 hp (35 kW) @ 6500 rpm
Torque	55 N·m (5.6 m·kgf, 40.6 ft·lbf) @ 5500 rpm
Dimensions	L 2040 mm (80.3 in) W 740 mm (29.1 in) H 1140 mm (44.8 in)
Seat height	770 mm (30.3 in)
Weight	159 kg (350 lb) (dry)

Yamaha SZR660 is a single-cylinder sportbike produced by Yamaha Motor Corporation from 1996 to 2001. It shares engine with Yamaha's XT660 line of dual-purpose on/off road motorcycles, but employs this engine within a Supermono package.

The 659-cc single-cylinder bike makes the most of its relatively modest power output by virtue of its light, stiff frame.

The Yamaha SZR660 was built in Italy and equipped with Italian made Paoli USD (Up Side Down) front forks and Marzocchi rear shock-absorber.

The chassis is from the Belgarda (Yamaha Italy) TZR 250 Sports two-stroke road bike. The engine is from the Yamaha XT660 Trail machine, so this bike is a hybrid. It was imported into Australia in small numbers by enthusiastic private Yamaha dealerships and was never a mainstream Yamaha Australia Model. In original pricing it exceeded $10,000, but values dropped after a few years. Today the acceptance of the SZR660 as a Learner Approved Motorcycle in most states has refirmed its values. As a learner bike it would provide reasonable performance and reliability.

The SZR660 is a testimonial to the development of CNC engineering. The proximity of the engine to the chassis and other components is demonstrably smaller than many other models and this machine could not have been built to such a standard in earlier years. Regular maintenance on this engine in such a confined space will definitely challenge the average owner. (for instance, to change the spark plug it is essential to use the special tool supplied in the kit (with a sponge internal plug "gripper") as well as removal of: the mirrors; fuel tank and droppoig the radiator from its rubber mountings.

The 660 engine incorporates a FIVE valve cylinder head, one of the last Yamahas manufactured with such a feature. There are three intake and two exhaust valves. The theory is that the smaller valves have a larger area at a lower weight than a four valve system and allow maximum intake flow and velocity.

The 660 engine has a unique external dry sump, in order to reduce overall engine size compared to a traditional wet sump engine.

The fuel tank incorporates an inbuilt fuel pump, to lift the contents of the tank to the twin carburettors.

The fuel system incorporates one slide carb and one butterfly carb. These are operated sequentially by a manually adjustable system.

Performance wise the chassis shines. Experienced motorcyclists have said that the bike is "the best handling machine I have ever ridden". Unfortunately the engine performance means that these statements are made after long descents. The SZR has difficulty exceeding 160 km/h in stock form, with its bulky muffler and restrictive carburettor system.

Comfort wise the chassis was designed with Junior Italian riders in mind, so it can be a little cramped, but the seat is comfortable and the vibrations of a big single are well dampened. The unique styling of the fuel tank can lead you to experience an unintentional "heimlich maneuver" when travelling downhill and hitting a large bump, but that's the worst that can happen to you on this bike.

Ownership Tips As the SZR is electric start only, make sure the battery is well maintained (it's a small battery for such a big engine) and if you manage to push start one of these bikes on a flat battery I believe you will need to be an olympic athlete.