High-performance lightweight two-stroke expansion chamber engineered to broaden the entire powerband from bottom to top while maximizing over-rev. Constructed using lightweight 20-gauge steel for the body and thicker 19-gauge steel for the header portion, featuring hand-pounded seams to optimize exhaust gas flow and deliver classic works-bike throttle response.
Specs & Details
- Manufacturer Part Number: 78-1359F
- Alternative Part Number: FMF 024055 / 1820-0174
- Component Type: 2-Stroke Expansion Chamber / Exhaust Pipe
- Material & Construction: Lightweight 20-gauge steel body with a 19-gauge header section and bare raw metal finish
Two-Stroke Vehicle Fitment
| Make | Model | Engine Type | Year Range |
| Yamaha | YZ 250 | Two-Stroke Motocross / Off-Road | 1999–2026 |
| Yamaha | YZ 250X | Two-Stroke Cross-Country | 2016–2026 |
TSO Garage Note
The quintessential works-finish pipe for riders chasing maximum over-rev and a razor-sharp, linear powerband across the entire RPM range. By combining a lightweight 20-gauge body with a beefier 19-gauge header section to handle high thermal stress, this chamber delivers instant throttle snap and smooth, unrestricted acceleration when you need to let a modern YZ scream.
