FMF Gnarly Pipe Expansion Chamber — Beta 250 RR / 300 RR 2013–2019

Bolt-on expansion chamber engineering that sharpens throttle response and widens the power spread across the rev range.

Fits: Beta 250 RR / 300 RR 2013–2019.

Why riders pick it:

• Expansion chamber tuning sharpens throttle response and broadens the power spread
• Works with your stock silencer or any FMF 2-stroke silencer
• Classic FMF chamber design refined for consistent, predictable power delivery
• Direct bolt-on installation, no tuning required

⚠️ For closed-course competition / off-road use only — not legal for street use in some states. Confirm your local regulations.

Not sure it fits your bike? Send us your year and model and we'll confirm.