We replaced all the flex header today by a new stainless steel header thicker and stronger but same lenght of old one. We tig welded to the existing elbow. My canister is install into an homemade plywood bracket like MTW canister system.

This should solve all issues. Changing of propeler may help to change resonnant freqency too. I begin to thrust ZDZ with their propeller recommandation. I am turning 6700 RPM hot on the 26x10 after only one gallon, 26x12 or 27x10 is the next step.

Daniel