I had the same thing happen to me 6 years ago. just changed to a different gear ratio went for a test run and boom. spark plug got loose and compression blew it just like yours.View attachment 918899 View attachment 918898 Anyone ever seen a champion Rj12 blow out like this ? No damage to threads and base still in head all pocelion gone and the plug boot hanging ! What you guys think??View attachment 918897
actually mine developed a knock that got worse' replaced the piston on the cyl that plug shot out and knock went away.Plug base still intact in head but everything else gone yes and no problem in cylinder I hope
actually mine developed a knock that got worse' replaced the piston on the cyl that plug shot out and knock went away.
Did it lose everything outward
kb 30 overWas it a cast piston or forged one