Wössner Pro Series Forged Piston for GAS GAS ECF 250, FANTIC TF 250, TF 250 ES CABALLERO and YAMAHA YZF 250 2005-2015

WOSSNER offers this piston kit for GAS GAS ECF 250, FANTIC TF 250, TF 250 ES CABALLERO and YAMAHA YZF 250 2005-2015. The piston slides in the cylinder and takes the force of the air-fuel combustion, passing it to the connecting rod and crankshaft.

Why choose a forged piston?

Instead of simply being cast, a forged piston is hot-pressed under very high pressure and then machined: its metal is denser and free of air pockets.

• Stronger when hot: it copes better with high revs, overheating and detonation.
• Lighter for the same strength: less stress on the connecting rod and bearings.
• Good to know: depending on the alloy, it expands a little more and is fitted with more clearance; slight noise when cold is normal.
• Why does it cost more? Forging tools, full machining and surface treatments cost more than simple casting.

Why choose WOSSNER?

Wössner has forged its own pistons since 1994: Molykote-coated skirt to reduce friction and ease running-in, kit supplied complete with rings, pin and clips.

When should you replace the piston?

Harder starting, loss of power, blue smoke, oil consumption or a knock when cold: these are the signs of a tired top end.

No manufacturer hour figure for this model. Cross-Mania guideline: compression check every 30 h in hard use and every 60 h for leisure.

Specifications and fitting tips

• Material: Aluminium
• Specificity: Double Bridge Forging / Gas Ported
• Piston compression: High compression
• Rings Quantity: 2
• Stroke: 2T
• Forged piston

Available in several sizes: choose the one that matches your cylinder (stamped size or measured bore). Diameters: A = 76.96 mm, C = 76.98 mm.

Cross-Mania tip: Measure the cylinder bore before ordering: the piston must match your cylinder size. Follow the manufacturer's break-in procedure and replace the top-end gaskets at the same time.

Also needed with this part

• Top-end gasket kit : ATHENA · COMETIC
• Spark plug : NGK 8 g · NGK
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L
• Air filter : TWIN AIR · TWIN AIR over-filter for FANTIC XE, XX…

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
FANTIC TF 250 2015
FANTIC TF 250 ES CABALLERO 2014
FANTIC TF 250 ES CABALLERO 2013
GAS GAS ECF 250 2015
GAS GAS ECF 250 2014
GAS GAS ECF 250 2013
GAS GAS ECF 250 2012
GAS GAS ECF 250 2011
GAS GAS ECF 250 2010
YAMAHA YZF 250 2007
YAMAHA YZF 250 2006
YAMAHA YZF 250 2005