PROX Carburettor Rebuild Kit for YAMAHA YZ 250 1991

On YAMAHA YZ 250 1991, the PROX 55.10531 carburettor rebuild kit fits in place of the original part. A carburettor that leaks, floods the engine or gives inconsistent carburation often needs new seals and a new float needle. This kit brings together the wear parts for a complete overhaul.

Key features

• NBR O-rings that resist the ethanol in today's fuels.
• Float bowl gasket in Interface material instead of the stock paper gasket, depending on the model.
• Jets in stock sizes, needle and seat depending on the model, fuel screw and small hardware.

Specifications

• Brand: PROX
• Manufacturer part number: 55.10531
• Weight: 30 g
• Engine: 2-stroke

When to replace it?

• Fuel running out of the overflow, float bowl overflowing.
• Unstable idle, hard starting, carburation that keeps changing.
• Hardened seals or a seeping float bowl.

When bringing a bike back into service after it has stood unused for a long time, during a full carburettor clean, or as soon as a leak appears.

Fitting tips

1. Strip and clean the carburettor (cleaning bath, compressed air), noting the original settings: float height, number of turns on the fuel screw.
2. Replace all the gaskets and O-rings in the kit, without reusing the old ones.
3. Set the float height according to the manual.
4. Reassemble, then set the idle and the fuel screw with the engine warm; check the colour of the spark plug after a few rides.

Why PROX?

ProX Racing Parts has been supplying engine and clutch parts to motocross riders since 1975, from its headquarters near Amsterdam. According to its catalogue, most of its parts are made in Japan, by manufacturers that also produce parts for the Japanese motorcycle makers.

Spare parts and items to plan

• Spark plug : NGK 3430 · NGK 3130
• Air filter : TWIN AIR · TECNIUM
• Air filter oil : LIQUI MOLY 500 ml · LIQUI MOLY 1 L

Frequently asked questions

Does the kit change the jetting?
No: the jets supplied are the original sizes for your bike.

Compatibility

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

Fits:
YAMAHA YZ 250 1991