PROX Connecting Rod Kit for APRILIA MX 125, PEGASO 125, RX 125 1989-2006

The PROX 03.7202 connecting rod kit is designed for APRILIA MX 125, PEGASO 125, RX 125 from 1989 to 2006. The connecting rod links the piston to the crankshaft and takes the most violent loads in the engine. Its big-end bearing and crank pin wear over the hours: play at the big end is the warning sign of a failure that can wreck the whole engine.

Specifications

• Brand: PROX
• Manufacturer part number: 03.7202
• Engine: 2-stroke

When to replace it?

• Vertical play at the big end at top dead centre.
• Side play out of tolerance, signs of overheating (bluing).
• Vibration and dull noise from the bottom end.

During a bottom end rebuild, at the intervals in the service manual, and without delay as soon as play appears at the big end.

Fitting tips

1. Replacing a connecting rod means pressing the crankshaft apart and then realigning it: with a dial indicator, you check the run-out, i.e. the deviation in rotation measured at the end of the shaft, which must stay within a few hundredths of a millimetre at most. Leave this job to a properly equipped workshop if you don't have a press and a truing stand.
2. Replace the crankshaft bearings and oil seals at the same time.
3. Check the big-end side play after assembly.
4. Close up the engine with a complete engine gasket kit and tighten to the manufacturer's torque.
5. Check the gearbox bearings, then fill up with fresh oil and fit a new spark plug.

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

• Crankshaft bearings and seals : see the selection
• Complete engine gasket kit : see the selection
• 2-stroke oil : LIQUI MOLY 1 L 3065 · LIQUI MOLY 1 L 3063
• Spark plug : NGK

Frequently asked questions

Can I fit the connecting rod myself?
Yes, if you have a press and a crankshaft truing stand; otherwise, an engine workshop can do it for you.

What else should I plan for?
The crankshaft bearing and seal kit, the complete engine gasket kit, the gearbox bearings if required, engine oil and a spark plug.

Compatibility

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

Fits:
APRILIA MX 125 2006
APRILIA MX 125 2005
APRILIA MX 125 2004
APRILIA PEGASO 125 1994
APRILIA PEGASO 125 1993
APRILIA PEGASO 125 1992
APRILIA PEGASO 125 1991
APRILIA PEGASO 125 1990
APRILIA PEGASO 125 1989
APRILIA RX 125 1998
APRILIA RX 125 1997
APRILIA RX 125 1996
APRILIA RX 125 1995
APRILIA RX 125 1994
APRILIA RX 125 1993
APRILIA RX 125 1992
APRILIA RX 125 1991
APRILIA RX 125 1990
APRILIA RX 125 1989