High-performance heavy-duty two-stroke expansion chamber engineered to deliver robust, tractor-like bottom-end and midrange power for big-bore off-road applications. Constructed from heavy-gauge 18-gauge carbon steel to withstand severe rock strikes, trail abuse, and extreme thermal cycling while significantly improving torque and throttle response across the entire RPM range.
Specs & Details
- Manufacturer Part Number: 78-1215
- Alternative Part Number: FMF 020038
- Component Type: 2-Stroke Expansion Chamber / Exhaust Pipe
- Material & Construction: Heavy-duty 18-gauge carbon steel with a nickel-plated finish
Two-Stroke Vehicle Fitment
| Make | Model | Engine Type | Year Range |
| Kawasaki | KX 500 | Two-Stroke Big-Bore Motocross / Desert | 1988–2004 |
TSO Garage Note
Part number 78-1215 is strictly the spring and O-ring hardware kit, whereas 020038 (or FMF part #020038 / often cross-referenced or historically sorted) is the legendary FMF Gnarly pipe built for the 1988–2004 Kawasaki KX500. If you're armoring up a big-bore two-stroke for the desert or tight single-track, the Gnarly's heavy 18-gauge steel wall is mandatory gear to keep your expansion chamber from collapsing on the first hard log or rock impact.
