METEOR High Compression Piston Kit Racing for HONDA CRF 450 2009-2012

The METEOR piston kit (Ø 95.95 to 95.98 mm depending on the size class) is designed for HONDA CRF 450 from 2009 to 2012. The piston takes the pressure of every combustion and passes it on to the connecting rod, thousands of times a minute. Over the hours it wears, its rings stop sealing properly and the engine loses compression: it starts less easily, pulls less hard and runs hotter.

Key features

• Italian piston manufacturer since 1952.
• Complete kit: piston, ring(s), pin and circlips.
• High-compression version: more torque and punch, best kept for an engine in good condition and well maintained.

Specifications

• Brand: METEOR
• Manufacturer part numbers: PC2318A, PC2318B, PC2318D
• Compression ratio: 12.9:1
• DLC-coated pin
• Piston diameter: A = 95.95 mm, B = 95.96 mm, D = 95.98 mm
• Available versions: A: ref. PC2318A; B: ref. PC2318B; D: ref. PC2318D
• Engine: 4-stroke

Choosing the right size class

The letters A, B, C… are very close diameter grades, one hundredth of a millimetre apart. Measure the cylinder bore with a bore gauge (diameter, ovality and taper) and choose the grade that gives the piston-to-cylinder clearance specified by the manufacturer. As a rule, grade A goes into a new or reconditioned cylinder, grade B into a cylinder that has already been run in. A scored or out-of-spec cylinder has to be reconditioned: you don't make up for its wear with a bigger grade.

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.
• On a four-stroke: oil consumption, blue smoke and a fouled spark plug.

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 30 to 60 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 the gaps staggered, never letting the ends of the oil control ring overlap.
4. 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.
5. Reassemble with a new top end gasket kit and tighten the cylinder head in a criss-cross pattern to the manufacturer's torque.
6. Refill the coolant, fit a new spark plug and change the oil with fresh engine oil and a new filter.
7. Break the engine in: warm it up gently, vary the revs and avoid sustained full throttle for the first hour.

Why METEOR?

A piston manufacturer since 1952, Italy's Meteor has supplied original equipment to manufacturers such as Piaggio and Innocenti. Its Meteor Racing division designs pistons for racing engines, both two-stroke and four-stroke.

Spare parts and items to plan

• Piston rings : VERTEX 590296000003 · VERTEX 590296000001
• Piston pin : WOSSNER · MOOSE
• Piston pin clips : WISECO · MOOSE
• Top-end gasket kit : PROX · MOOSE
• Spark plug : NGK 7764 · NGK 6213
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L

Frequently asked questions

Does the kit include the gaskets?
No: the kit contains the piston, rings, pin and circlips. Add a top end gasket kit, because a head or base gasket can never be reused.

Which size should I order?
Measure your cylinder: A, B, D correspond to different actual diameters (95.95 to 95.98 mm). Choose the class that gives the piston-to-cylinder clearance specified by the manufacturer.

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.

Compatibility

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

Fits:
HONDA CRF 450 2012
HONDA CRF 450 2011
HONDA CRF 450 2010
HONDA CRF 450 2009