WISECO Forged Piston for YAMAHA YFB 250 TIMBERWOLF 2WD, YFM 250 BEAR TRACKER 2WD 1992-2005

WISECO offers this piston kit for YAMAHA YFB 250 TIMBERWOLF 2WD, YFM 250 BEAR TRACKER 2WD 1992-2005. 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 WISECO?

Wiseco has forged its pistons in Mentor (Ohio, USA) since 1941 and controls the whole process, from aluminium bar to the friction-reducing ArmorGlide skirt coating. Its pistons are developed with Team Honda HRC in Supercross (450 class since 2018).

When should you replace the piston on your YAMAHA YFB 250 TIMBERWOLF 2WD?

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 20 h in hard use and every 40 h for leisure.

Specifications and fitting tips

• Material: Aluminium
• Piston compression: Standard
• Piston type: Forged

Available in several sizes: choose the one that matches your cylinder (stamped size or measured bore).

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 : see the selection
• Spark plug : see the selection
• 2-stroke oil : LIQUI MOLY 1 L 3065 · LIQUI MOLY 1 L 3063
• Air filter : see the selection

Compatibility

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

Fits:
YAMAHA YFB 250 TIMBERWOLF 2WD 2001
YAMAHA YFB 250 TIMBERWOLF 2WD 2000
YAMAHA YFB 250 TIMBERWOLF 2WD 1999
YAMAHA YFB 250 TIMBERWOLF 2WD 1998
YAMAHA YFB 250 TIMBERWOLF 2WD 1997
YAMAHA YFB 250 TIMBERWOLF 2WD 1996
YAMAHA YFB 250 TIMBERWOLF 2WD 1995
YAMAHA YFB 250 TIMBERWOLF 2WD 1994
YAMAHA YFB 250 TIMBERWOLF 2WD 1993
YAMAHA YFB 250 TIMBERWOLF 2WD 1992
YAMAHA YFM 250 BEAR TRACKER 2WD 2005
YAMAHA YFM 250 BEAR TRACKER 2WD 2004
YAMAHA YFM 250 BEAR TRACKER 2WD 2003
YAMAHA YFM 250 BEAR TRACKER 2WD 2002
YAMAHA YFM 250 BEAR TRACKER 2WD 2001
YAMAHA YFM 250 BEAR TRACKER 2WD 2000
YAMAHA YFM 250 BEAR TRACKER 2WD 1999