DYNOJET Jet Kit - Honda TRX400X Q121

Carburetor tuning is critical to maximizing your TRX400X's potential, especially as you modify your engine or exhaust system. The DYNOJET Jet Kit gives you precise, repeatable fuel curve adjustments without guesswork—ensuring your quad delivers consistent power across the entire RPM range. Whether you're chasing 5% gains on a stock setup or targeting race-oriented performance, this fully adjustable kit lets you dial in the exact jetting your specific build demands.

DYNOJET's Q121 kit includes multiple stage options tailored to your modification level, so you can upgrade your tuning as your TRX400X evolves. Each stage is engineered to improve both power output and rideability, giving you the control that separates a properly jetted quad from one left on the table.

• MPN: Q121
• Application: Honda TRX400X
• Fitment: Vehicle-specific
• Installation: Bolt-on carburetor jetting
• Fully adjustable needles
• Stage 1: ~5% power increase
• Stage 2: ~8% power increase
• Stage 3: ~10-15% power increase
• Stage 7: Race-only configuration
• Compatible: Stock or modified engines
• Compatible: Stock or modified exhaust
• Improves power and drivability
• Manufacturer: DYNOJET