WISECO Racer Elite Forged Piston for SUZUKI RM 125 2004-2010

The WISECO Racer Elite WRE914M05400 forged piston (Ø 54 mm) is designed for SUZUKI RM 125 from 2004 to 2010. A forged piston is made by squeezing a hot aluminium slug in a press, instead of pouring the metal into a mould. The metal is denser and stronger: the piston copes better with high revs and heat, which makes it the choice for racing engines.

Specifications

• Brand: WISECO
• Manufacturer part number: WRE914M05400
• EAN code: 91405400
• Piston diameter: 54 mm
• Weight: 230 g
• Engine: 2-stroke

When to replace it?

• Loss of power, sluggish pick-up, harder starting: compression is dropping.
• Piston slap on a cold engine, getting more and more noticeable.
• On teardown: vertical scoring on the skirt, stuck or worn rings, thick carbon on the crown.

Replace the piston as set out in your bike's service manual, sooner if you race, and straight away as soon as these symptoms appear. As a Cross-Mania guideline, plan for a new piston every 20 to 40 hours of engine running depending on whether you race or ride for fun. Always measure the cylinder at the same time: a new piston in an oval cylinder won't last.

Fitting tips

1. Clean the cylinder and check it: diameter, ovality, taper and condition of the bore coating.
2. Check the end gap of each ring in the cylinder against the figures in the manual or the manufacturer's instructions.
3. Fit the rings with the mark facing up and each gap correctly located on its locating pin.
4. Check the small-end needle bearing and the pin: at the slightest play, tight spot or marked needle, replace the bearing.
5. Fit the piston with its arrow pointing to the exhaust side, oil the pin and the small end, then fit the circlips without distorting them, gap opposite the notch. A circlip that has been taken out is replaced with new piston pin circlips, never refitted.
6. Reassemble with a new top end gasket kit and tighten the cylinder head in a criss-cross pattern to the manufacturer's torque.
7. Refill the coolant and fit a new spark plug.
8. Break the engine in: warm it up gently, vary the revs and avoid sustained full throttle for the first hour.

Why WISECO?

Based in Mentor, Ohio, Wiseco designs, forges and machines its parts in the United States. Pistons, valves and clutch parts: the brand is known for forged parts built for hard-working engines.

Spare parts and items to plan

• Piston rings : WOSSNER · VERTEX
• Piston pin : WOSSNER WP032 · WOSSNER CW15
• Piston pin clips : VERTEX · WOSSNER
• Top-end gasket kit : ATHENA · PROX
• Small end needle bearing : PROX · NTN
• Spark plug : NGK 4492 · NGK 3230
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 2-stroke oil : LIQUI MOLY 1 L 3065 · LIQUI MOLY 1 L 3063

Frequently asked questions

Does the piston come complete?
Yes: piston, pin, circlips and ring(s). The top end gasket kit has to be ordered separately, because a head or base gasket can never be reused.

Can I replace just the rings later?
Yes, as long as the piston and cylinder are still within tolerance. Replacement rings can be ordered on their own, as can the piston pin and the circlips.

Should I replace the small-end needle bearing?
It isn't included. Check it at every piston change and replace the needle bearing at the slightest play or tight spot.

Compatibility

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

Fits:
SUZUKI RM 125 2010
SUZUKI RM 125 2009
SUZUKI RM 125 2008
SUZUKI RM 125 2007
SUZUKI RM 125 2006
SUZUKI RM 125 2005
SUZUKI RM 125 2004