🔎 Key Observations

 Here's the detailed comparison between your Old Timing Map (peaking at 6,000 RPM) and the New Timing Map (peaking at 8,000 RPM):

🔎 Key Observations

  1. Early RPM Zone (1,500 - 4,500 RPM)
    🔹 Both timing maps are nearly identical to maintain stable low-end torque.

  2. Midrange Zone (5,000 - 7,000 RPM)
    🔹 The new map advances timing slightly more aggressively to compensate for reduced low-end pressure caused by your taller exhaust port.

  3. Peak Timing Point (Old vs New)
    🔹 The Old Map peaks at 6,000 RPM to maximize midrange punch (ideal for smaller bore engines).
    🔹 The New Map peaks at 8,000 RPM to match your improved exhaust duration and extend powerband for higher top speed.

  4. High RPM Zone (8,500 - 11,000 RPM)
    🔹 The New Map retards timing gradually to protect your piston crown and stabilize combustion pressure at high RPM.

🚨 Why the New Map Will Help You Hit 200 km/h+

✅ Your taller exhaust port allows higher RPM power, so a later timing peak matches your revised powerband.
✅ Your 60mm bore requires slightly slower flame propagation, which benefits from a later timing peak for maximum cylinder pressure at higher RPM.
✅ Progressive retardation in the New Map prevents detonation and overheating in the extended RPM range.

🔧 Final Advice

  • If you want better midrange acceleration, you can try peaking timing slightly earlier (around 7,500 RPM) but keep retardation steady beyond 8,500 RPM.
  • To further stabilize top-end power, consider slightly increasing your main jet to improve high RPM fueling.

Would you like guidance on carb tuning, plug heat range changes, or gearing adjustments to fully match this optimized timing map? 🚀

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