High-performance two-stroke expansion chamber engineered to broaden the powerband across the entire RPM range, increasing low-end torque, mid-range punch, and top-end over-rev. Constructed using durable stamped steel with smooth hand-welded seams and a nickel-plated finish to deliver clean throttle response and maximum exhaust flow.
Specs & Details
- Manufacturer Part Number: 78-1090F
- Alternative Part Number: FMF 020301 / 1820-0083
- Component Type: 2-Stroke Expansion Chamber / Exhaust Pipe
- Material & Construction: Stamped steel construction with nickel-plated finish
Two-Stroke Vehicle Fitment
| Make | Model | Engine Type | Year Range |
| Yamaha | YZ 250 | Two-Stroke Motocross / Off-Road | 1997–1998 |
TSO Garage Note
The ideal powerband tuning upgrade for late-90s steel-frame YZ250s. The Fatty smooths out abrupt power hits and broadens pull from bottom to top, giving you immediate throttle response and improved over-rev whether you are railing motocross ruts or opening it up across open terrain.
