Muc-Off Exhaust Bung - Motorcycle Exhaust Plug for Washing

The Muc-Off Motorcycle Exhaust Bung is the plug that prevents water from entering the exhaust while washing or performing maintenance. It is constructed with a flexible silicone rubber body and sleeve, two separable parts that make it compatible with both 2-stroke and 4-stroke engines: remove the sleeve for 2-strokes, leave it on for 4-strokes. The tapered design fits most exhaust pipe diameters, screws into place in an instant, and has a lanyard that makes removal immediate.

✓ Strengths

• Two-part construction – with and without sleeve: one bung for 2-stroke and 4-stroke.
• Tapered design – fits most exhaust pipe sizes.
• Watertight seal – water and contaminants stay out of the exhaust pipe.
• Lanyard included – easy removal and, most importantly, hard to forget.
• Durable and flexible silicone – deforms to fit and returns to shape.
• Twist-in installation – no tools, a few seconds.

Technical specifications

Data sources: official Muc-Off data sheet (material, two-part construction, 2-stroke and 4-stroke compatibility, lanyard, instructions for use, starting warning, code 20653, weight 183 g) and official supplier price list (EAN, customs code, country of origin). Compatible diameters are not published by either the manufacturer or the consulted retailers.

How to use

1. Allow the exhaust to cool completely.
2. For a 2-stroke engine: slide off the black silicone sleeve.
3. For a 4-stroke engine: leave the sleeve on.
4. Twist the bung into the exhaust opening until a seal is created.
5. Remove it before starting the engine.
6. Store in a cool, dry place.

Recommended products and accessories

• Muc-Off Nano Tech Motorcycle Cleaner 1L – the cleaning solution for which the bung is needed.
• Muc-Off Motorcycle Protectant 500ml – the protectant to use after rinsing.
• Muc-Off 5X Premium Brush Kit – the brush set for a complete wash.
• Muc-Off Off-Road All-Weather Chain Lube – the lubricant to reapply after washing.

Who it's perfect for

Anyone who washes their motorcycle with a pressure washer knows that the exhaust pipe is the most delicate point: a poorly aimed jet is enough for water to enter the muffler, where it stays and rusts for weeks. On a motocross or enduro bike, which is washed after every ride, the problem arises every time. This bung solves it in ten seconds and, thanks to its two-part construction, works on both two-stroke and four-stroke engines: it's the classic five-euro accessory that saves hundreds of euros in damage. The only thing never to forget is to remove it before starting the engine.

Frequently Asked Questions

Will it fit my exhaust?
Muc-Off states a tapered design suitable for most exhaust pipe diameters, but does not publish precise measurements, nor do retailers report them. We prefer to say this rather than invent a millimeter range: if you have a very large or very small exhaust pipe, write to us and we'll check together before ordering.

How does it work for 2-stroke and 4-stroke engines?
The bung is made of two parts: a body and a silicone sleeve that slides off. For a two-stroke engine, remove the sleeve; for a four-stroke, leave it on. This is Muc-Off's solution to cover both cases with a single item.

What happens if I start the engine with the bung inserted?
The manufacturer warns that the bung can be violently ejected from the exhaust. This is a real risk for both those nearby and the bung itself. The lanyard is precisely for this: to let it hang clearly visible so you notice it before turning the key.

Does the exhaust need to be cold?
Yes, the first step of the official instructions is to allow the exhaust to cool completely. Silicone is flexible but is not made for contact with a scorching hot exhaust pipe that has just been turned off.

Is it really necessary if I wash by hand?
Less so than with a pressure washer, but it's still useful: water dripping into the exhaust pipe while rinsing the motorcycle is the most common cause of internal muffler rust. On a motorcycle left stationary after washing, that moisture remains there for days.

How should it be stored?
In a cool, dry place, as indicated by the manufacturer. Silicone doesn't like heat and prolonged direct light: hanging it in the garage is better than leaving it in the trunk in the sun.