DYNOJET Jet Kit - Stage 1 - Yamaha 4190

If you're running stock jetting on your Yamaha, you're leaving performance on the table—especially once you add even modest exhaust or intake modifications. The DYNOJET Jet Kit Stage 1 recalibrates your fuel delivery to match your engine's actual air intake, restoring lost throttle response and unlocking a solid 5% power increase across the powerband. This is a bolt-on tuning solution that transforms how your bike feels without requiring engine work or professional dyno time.

Designed for stock engines paired with either stock or mildly modified exhaust systems, this kit gives you full control over jetting adjustments—letting you dial in the perfect fuel curve for your specific setup and riding conditions. Whether you're prepping for track days or simply want your bike to perform as intended, Stage 1 delivers measurable gains in power and throttle response.

• Manufacturer: DYNOJET
• Part Number: 4190
• Kit Level: Stage 1
• Vehicle Application: Yamaha
• Power Increase: ~5%
• Fitment: Stock or modified pipes
• Engine Requirement: Stock displacement
• Air Filter: Stock compatible
• Adjustability: Fully tunable
• Installation: Bolt-on
• Benefits: Improved drivability, corrected fuel mapping