Back in 2011 I rebuilt my blown di. The cause looked to be a loose intake manifold rubber boot clamp allowing extra air into the cylinder causing it to run lean and blow the cylinder. 13 years later and it fired right up again this spring. At 22 years old I‘m not sure how much longer she’ll go but I still running her like I stole her. In this time , I’ve only replace a wear ring and a few rectifiers.