PROX Timing Chain for HONDA TRX 250, TRX 350 2000-2024

The PROX 31.1480 timing chain is designed for HONDA TRX 250, TRX 350 from 2000 to 2024. The timing chain drives the camshafts from the crankshaft and keeps the valves in sync with the piston. As it stretches, it throws the valve timing out and pushes the tensioner to the end of its travel.

Specifications

• Brand: PROX
• Manufacturer part number: 31.1480
• Engine: 4-stroke

When to replace it?

• Rattling or chain noise on the timing side, especially at idle.
• Tensioner at the end of its travel.
• Timing marks that no longer line up.

At the intervals in the service manual, and as soon as the tensioner reaches the end of its travel. Check the sprockets and the guides at the same time.

Fitting tips

1. Set the engine at top dead centre on the compression stroke, marks aligned, before removing anything.
2. On most motocross engines the chain is endless, with no master link: replacing it means removing the crankshaft sprocket or a camshaft, as described in the manual.
3. Line the camshafts up with their timing marks again, then put the tensioner back under tension.
4. Turn the engine over two full turns by hand and check the timing again before starting.
5. Refit with a valve cover gasket in good condition.

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

• Valve cover gasket : see the selection
• Valve shims : see the selection
• 4-stroke engine oil : MOTUL 10W50 · LIQUI MOLY 10W40 1 L

Frequently asked questions

Should I replace the tensioner?
Check it: a worn tensioner, or one at the end of its travel, must be replaced along with the chain.

Compatibility

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

Fits:
HONDA TRX 250 2024
HONDA TRX 250 2023
HONDA TRX 250 2022
HONDA TRX 250 2021
HONDA TRX 250 2020
HONDA TRX 250 2019
HONDA TRX 250 2018
HONDA TRX 250 2017
HONDA TRX 250 2016
HONDA TRX 250 2015
HONDA TRX 250 2014
HONDA TRX 250 2013
HONDA TRX 250 2012
HONDA TRX 250 2011
HONDA TRX 250 2010
HONDA TRX 250 2009
HONDA TRX 250 2008
HONDA TRX 250 2007
HONDA TRX 250 2006
HONDA TRX 250 2005
HONDA TRX 250 2004
HONDA TRX 250 2003
HONDA TRX 250 2002
HONDA TRX 250 2001
HONDA TRX 350 2006
HONDA TRX 350 2005
HONDA TRX 350 2004
HONDA TRX 350 2003
HONDA TRX 350 2002
HONDA TRX 350 2001
HONDA TRX 350 2000