Honda CB400N Superdream with hole in piston, what is the possible cause?

This video shows a possible cause of why a there is a hole in your piston for a Honda CB400T Dream, CB400N Superdream, CM400, CM450, CB450DX, CB450 Nighthawks, and other models that used the Hitachi Stator and ignition system. It explains briefly how the stator ignition components work and what part of the stator assembly can fail that may cause a holed piston. Recorded in Spain and the UK in January 2025. Many thanks to D Carter for allowing me to use his picture for this video.

[@sergemoreillon1236]

Hello! Back in 1981, I had a Yamaha XS650 447 type and it happened me 2 times !!! The problem came (after analysis) from a simple BAD spring in the centrifugal ignition advance regulator... Good thing to change the ignition with electronic systems kits on before 80's bikes (just my advice)

[@Adminstormdogmedia]

Very informative Rog, great video

[@SplendidProgress]

I had one of these in the early 80's, really good bike but they had an oil feed problem to the top end and it punched a con rod through the crankcase. Shame

[@eddiepiecart6030]

Good old detonation damage. Bad fuel. Faulty ignition Heavy carbon deposit

[@jamesstirling3792]

Plug is too hot

[@mpista7182]

too lean too hot