ATHENA Connecting Rod Kit for YAMAHA WRF 250, YZF 250 and GAS GAS ECF 250, ECF 300 2003-2015

The ATHENA P40321020 connecting rod kit is designed for YAMAHA WRF 250, YZF 250 and GAS GAS ECF 250, ECF 300 from 2003 to 2015. 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.

Key features

• High-strength forged connecting rod made in Japan.
• Supplied with crank pin, needle bearing and thrust washers, depending on the application.
• Fits to original dimensions, with no modification.

Specifications

• Brand: ATHENA
• Manufacturer part number: P40321020
• EAN code: 8057018267385
• Weight: 550 g
• Engine: 4-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 ATHENA?

Athena, an Italian company founded in 1973 near Vicenza, designs gaskets, pistons and cylinder kits for motorcycles. An OEM supplier to KTM, Ducati, Fantic, Piaggio and Triumph and a partner of the MXGP world championship, it develops its parts on the test bench and on the track with racing teams.

Spare parts and items to plan

• Crankshaft bearings and seals : ALL BALLS
• Complete engine gasket kit : MOOSE
• Gearbox bearings : HOT RODS TBK0066 · HOT RODS TBK0105
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L
• Spark plug : NGK 3521 · NGK 4218

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:
GAS GAS ECF 250 2015
GAS GAS ECF 250 2014
GAS GAS ECF 250 2013
GAS GAS ECF 250 2012
GAS GAS ECF 250 2011
GAS GAS ECF 250 2010
GAS GAS ECF 300 2015
GAS GAS ECF 300 2014
GAS GAS ECF 300 2013
YAMAHA WRF 250 2013
YAMAHA WRF 250 2012
YAMAHA WRF 250 2011
YAMAHA WRF 250 2010
YAMAHA WRF 250 2009
YAMAHA WRF 250 2008
YAMAHA WRF 250 2007
YAMAHA WRF 250 2006
YAMAHA WRF 250 2005
YAMAHA WRF 250 2004
YAMAHA WRF 250 2003
YAMAHA YZF 250 2013
YAMAHA YZF 250 2012
YAMAHA YZF 250 2011
YAMAHA YZF 250 2010
YAMAHA YZF 250 2009
YAMAHA YZF 250 2008
YAMAHA YZF 250 2007
YAMAHA YZF 250 2006
YAMAHA YZF 250 2005
YAMAHA YZF 250 2004
YAMAHA YZF 250 2003