Wossner Forged Piston Kit – KTM / Husaberg 450 (A & B Sizes)

🛠️ Description

Wossner pistons are precision-forged in Germany to deliver maximum performance and reliability for KTM and Husaberg 450 engines. These are OEM-style “A” and “B” size pistons, designed to match factory cylinder manufacturing tolerances for a perfect fit and long service life.

What’s the difference between an A and a B piston?
From the factory, engine cylinders vary ever so slightly in bore size—often by just a few hundredths of a millimeter. Manufacturers (and Wossner) offer pistons in graded sizes so you can select the correct one for your cylinder:

• A Piston (94.95 mm) → Best suited for cylinders at the lower end of the bore tolerance.

• B Piston (94.96 mm) → Best suited for cylinders at the upper end of the bore tolerance.

This means if your cylinder measures tight (closer to 95.00 mm), you’ll want an A piston. If it measures slightly looser (closer to 95.01 mm), a B piston ensures proper clearance. The difference is small, but choosing correctly prevents excess wear, blow-by, and premature failure.

👉 Always measure your cylinder before ordering. If in doubt, consult a machine shop for an exact bore measurement.

✅ What’s Included

• Forged Wossner piston (A or B size)

• Piston ring set (RIK95.00/2)

• Wrist pin (#WP037-SP)

• Circlips (#CW19)

📦 Fitment

• 2008–2011 KTM 450 EXC-R

• 2008–2009 KTM 450 XCR-W

• 2010 KTM 450 XC-W Champions Edition

• 2010–2011 KTM 450 XC-W Six Days

• 2009–2012 Husaberg FC 450

• 2010–2012 Husaberg FX 450

🛡️ Warranty Info

All Wossner pistons are covered by manufacturer warranty against defects in material or workmanship. Warranty does not cover damage due to improper installation, lack of lubrication, or incorrect piston sizing. Always measure your bore before installing.

🔑 Key Features

• Precision German forging with tight wall clearances for quiet operation

• Skirt coating reduces friction and aids break-in

• Enhanced wrist pin oiling slots for longer life

• Two-ring design for maximum sealing and performance

• 11.9:1 compression ratio (stock replacement)