From a Yamaha press release:

Replica model of the MotoGP GP250cc class-leading YZR250 factory machine

Release of the 2003 Model Yamaha Production Road Racer TZ250

Yamaha Motor Co., Ltd. (YMC) will release on the Japanese market the 2003 model of the production road racer TZ250 that has won the trust of road race competitors for the high level of competitiveness it achieves in race categories from MotoGP GP250cc class to national level racing. Featuring numerous detail improvements that further boost engine and chassis performance, the 2003 model TZ250 will be released on Nov. 25, 2002.

The 2003 model TZ250 newly adopts several more features from the factory racer YZR250, such as YZR250 type cylinder body, cowling, seat and front fender, giving this model top-class competitive potential for the MotoGP GP250cc class.

Ordering and sales of this model will be conducted through Yamaha RSS shops nationwide. Meanwhile, the TZ125 will continue to be sold in its present specification.

Release date: Nov. 25 for TZ250

Advance ordering dates:Sept. 1, 2002 ~ Nov. 30, 2002 for TZ250

Achieving performance potential to compete with the best in the MotoGP GP250cc class based on a YZR250 replica concept

Product Summary

The 2003 model TZ250 adopts various technologies from the MotoGP factory machine YZR250 in the form of numerous spec changes in the engine and chassis to achieve an extremely high level of competitiveness. The competitive potential it achieves makes this model worthy of being called a YZR250 replica.

The engine improvements include the adoption of a YZR250 type cylinder body, and new carburetor settings, etc., that provide better power feeling across the full rpm range and improved acceleration performance. The chassis adopts a YZR250 type cowling, seat and front fender for improved aerodynamics and top-speed performance, making for more stable handling performance at high speeds.

The TZ250 was the championship machine in the 2001 All Japan Championships, and in the 2002 All Japan series it swept the top four places in each of the first five rounds of the season. This kind of consistent competitiveness has won the TZ250 the trust of riders in the Japanese market.

Main New Features

–YZR250 type cylinder body (special type YPVS valve incorporating exhaust branch function) adopted

While maintaining the outstanding characteristics of the sand cast type crankcase, liquid-cooled 2-stroke, 90°V-twin engine of the existing model, engine improvements have been made that include the adoption of a YZR250 type cylinder body (special type YPVS valve incorporates exhaust branch function), new exhaust timing and a new shape for the initial scavenging section of the crankcase. The combined effect of these improvements boosts performance across the entire rpm range. (The existing model features a slide-type YPVS valve).

In particular, the new cylinder and drum-type YPVS valve boost performance in the low- to mid-speed range and contribute to reduced exhaust noise. The new exhaust timing improves performance in the high-speed range, while the new initial scavenging section shape contributes to better torque characteristics.

–WPC finish piston for greater durability
The piston features a new shape in the upper portion of the pin boss for optimized strength balance plus a WPC finish on its outer surface for greater durability and reduced friction. Durability has also been increased by changing the shape of the crankcase journal section. (WPC treatment is a type of treatment for increasing the strength of the surface layer of a metal that involves high-speed peening of the metal with a shot of just a few microns. The high-speed peening heats up the surface to the point where it melts once. Then it is rapidly cooled to produce stronger crystallization of the metal.)

–YZR250 type cowling adopted for improved high-speed performance
The adoption of a YZR250 type cowling with right-left opposed ducts, a YZR250 type seat and front fender combine to provide better aerodynamics and boost top speed. The accompanying improvement in wind protection also helps reduce rider fatigue, while the stronger down-force effect improves handling stability at high speeds. Also, the shapes of the passages from the ducts to the air box have been optimized to provide more even supply of ram air to the two cylinders.

-Other specification changes
Other improvements include (1) new carburetor settings,
(2) new primary reduction
ratio (1.888 -> 1.938),
(3) new shape for the front brake hose passage for better serviceability,
(4) lightweight, shorter silencer (overall length: 307mm -> 242mm/lighter weight) and
(5) a new CDI unit with revised ignition characteristics, new solenoid duty ratio characteristics and YPVS operation characteristics.

Yamaha Road Racer TZ250 Technical Specifications

Overall length x width x height 1995mm x 650mm x 1163mm
Wheelbase, 1342mm
Minimum ground clearance, 112mm
Dry weight, 102kg
Engine type, Liquid-cooled, 2-stroke, crankcase
reed valve
Cylinder arrangement, V-Twin
Displacement, 249cc
Bore x Stroke, 54.0mm x 54.5mm
Compression ratio, 7.2~7.7: 1
Maximum power, 93PS(68.4kW)/12,500rpm
Maximum torque, 5.5kgf-m(53.9N-m)/11,750rpm
Starting system, Push start
Lubrication, Pre-mix
Engine oil capacity, 0.5liter
Fuel tank capacity, 23liter
Carburetion, TMX 32 x 2
Ignition system, C.D.I.
Primary / Secondary reduction ratios, 2.524 / 2.571
Clutch type, Dry multiplate, coil spring
Transmission type, Constant mesh, forward 6-speed
Gear ratios
1st: 1.938
2nd: 1.476
3rd: 1.238
4th: 1.091
5th: 1.000
6th:0.926
Frame type, Diamond
Caster/Trail, 22°/82mm
Tire size(Front/Rear), 120/60R-17 / 165/55R-17
Brake type(Front/Rear), Hydraulic, double disc/ Hydraulic, single disc
Suspension type(Front/Rear)Telescopic/Swing arm