HOT CAMS Stage 1 Exhaust Camshaft for YAMAHA YZF 250 2017-2018

On YAMAHA YZF 250 from 2017 to 2018, the HOT CAMS Stage 1 4325-1E camshaft fits in place of the original part. Driven by the timing chain, the camshaft opens and closes the valves at the right moment. A worn or marked camshaft costs power; a new one gives the engine back its original efficiency.

Specifications

• Brand: HOT CAMS
• Manufacturer part number: 4325-1E
• Engine: 4-stroke

When to replace it?

• Lobes scored, pitted or worn at the tip.
• Valve clearances that keep changing, or timing noise.
• Marked camshaft journals, lack of lubrication.

Check the camshaft every time you set the valve clearance. As a Cross-Mania guideline, on a 4-stroke motocross bike this check comes round roughly every 15 to 30 hours; your bike's manual gives the exact interval. Replace the camshaft as soon as a lobe is marked.

Fitting tips

1. Note the valve timing marks before taking anything apart (manufacturer's marks on the sprocket and head).
2. Oil the lobes and journals with clean engine oil before fitting the camshaft.
3. Tighten the journal caps in a criss-cross pattern to the manufacturer's torque, then check the timing over several turns.
4. Set the valve clearance with suitable shims: a new camshaft often changes the clearances.
5. Replace the decompressor or its springs if they are tired.

Spare parts and items to plan

• Timing chain : WISECO · PROX
• Cam chain tensioner : GE.CO
• Valve cover gasket : MOOSE 817852MSE · MOOSE 819030MSE
• Valve shims : MOOSE · HOT CAMS

Frequently asked questions

What does Stage mean?
Stage 1, 2 or 3 is a cam profile more or less aggressive than stock. Check the Hot Cams instructions to see whether your engine needs valve springs or other parts with this profile.

Do the valves need adjusting afterwards?
Yes, always: measure each valve's clearance with the engine cold and correct it.

Compatibility

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

Fits:
YAMAHA YZF 250 2018
YAMAHA YZF 250 2017