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TZ250/125
Product Info  

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.

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.

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.)

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