TSP Complete Billet Head — Yamaha YZ250 1999-on Low/Medium/High Compression

LOW: The new LOW comp design IS THE SAME AS the previous MED design that was used for the X models. It has been renamed to allow changes to the higher comp heads. It is still best suited to the X models where the rider wants smoother, crisper power delivery, especially at part throttle. With appropriate jetting changes it makes a big improvement to the X model.

MEDIUM: The new MED comp design IS THE SAME AS the previous HIGH design that was used for the standard YZ250 models for many years. It has been renamed to allow the introduction of a new higher comp design. It can either be used on the X models where the rider wants a big increase in bottom/mid over stock, or it can be used on the std YZ models to give smooth power everywhere and a much more reliable engine. It is lower compression than the stock YZ head but still produces MORE power and WAY smoother delivery. This is the best design to use for high level MX where the rider ir revving the engine very hard.

HIGH: This is a brand new design which is still suitable for 98 RON fuel at sea level. It can also be used at elevation to give similar power to the Med head at sea level.
This design is the same compression as stock (already a very high comp head!) but with a much better design. It produces a big increase in bottom/mid power over stock but doesnt rev out as far as the Med design. Best suited to Offroad or MX where big gains in bottom/mid are needed and where the engine will not be revved too hard.