What is the spark plug gap for the CT90 / Trail 90? March 03, 2025 22:00 Updated Gap specification: 0.6 - 0.7 mm (0.024 - 0.028 in.) Related to CT90 spark plug gap Related articles Honda CT90 / Trail 90 Spark Plugs How to set the Ignition Timing on the Honda CT90 / Trail 90 What engine oil should I use on my Honda CT90 / Trail 90? Installing a Regulator / Rectifier on the Honda CT90 / Trail 90 How to set the Valve / Tappet Clearance on the Honda CT90 / Trail 90