PROX Piston Kit ref. 01.6601.B for HUSQVARNA TC 570, TC 610, TE 570, TE 610 1999-2003

The PROX 01.6601.B piston kit (Ø 97.95 mm) is designed for HUSQVARNA TC 570, TC 610, TE 570, TE 610 from 1999 to 2003. 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

• Made mainly in Japan, by OEM manufacturers (ProX catalogue).
• Complete kit: piston, rings, pin and circlips.
• Compatible with stock coated (Nikasil) and sleeved cylinders. Not suitable for chrome-plated cylinders.
• Diameter classes to the hundredth of a millimetre for a precise piston-to-cylinder clearance.

Specifications

• Brand: PROX
• Manufacturer part number: 01.6601.B
• Size: B (check that it matches your cylinder)
• Piston diameter: 97.95 mm
• Weight: 500 g
• Engine: 4-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.
• 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 PROX?

Founded in 1975 and based near Amsterdam, ProX specialises in engine and clutch wear parts for off-road bikes. The brand has most of its range made in Japan, by OEM suppliers, for quality on a par with the original parts.

Spare parts and items to plan

• Piston rings : PROX · WOSSNER
• Piston pin : WOSSNER WP009-SP · WOSSNER CW22
• Piston pin clips : WOSSNER
• Top-end gasket kit : ATHENA S410220015001 · ATHENA S410220001002/1
• Spark plug : NGK 5096 · NGK 7411
• Coolant : LIQUI MOLY 1 L · TWIN AIR
• 4-stroke engine oil : LIQUI MOLY 10W40 1 L · MOTUL 10W50

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.

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:
HUSQVARNA TC 570 2002
HUSQVARNA TC 570 2001
HUSQVARNA TC 610 2003
HUSQVARNA TC 610 2002
HUSQVARNA TC 610 2001
HUSQVARNA TC 610 2000
HUSQVARNA TC 610 1999
HUSQVARNA TE 570 2002
HUSQVARNA TE 570 2001
HUSQVARNA TE 610 2003
HUSQVARNA TE 610 2002
HUSQVARNA TE 610 2001
HUSQVARNA TE 610 2000
HUSQVARNA TE 610 1999