been to sydney and picked up the derelict cb350 donor bike- anyone know an easy way to get a broken spark plug out. no hex left but thread and ceramic still in plug hole.????
Your pulling the head off? if so go from the combustion chamber side, bust the electrode off and use a suitable sized course thread bolt with a slight taper on the end...Id suggest an easy out but you will need a normal rotation thread(do they even make them in easy outs?) as you are going at it backwards
hope to get it out from outside and check internals with an endoscope.easy outs are no good as they exopand the thread as the internal hole has no bottom.
anything remaining on the plug you can tack weld to? honestly head off is in the end going to be the easiest...
Plus heat... and soaking overnight with penetrating oil... use every trick in the book.... but I have to agree that taking the head off is easiest... I mean... if the plug is that bad... I wouldnt be trusting the engine has been looked after so a quick check and freshen up would be a good thing.
need the head, barrells and pistons.expect a rebuild but was cheaper to buy a derelect bike than the individual parts.
So why bother making life difficult trying to remove the spark plug just so you can see down the bore... before you take the head off anyway... Take the head off... see what is needed and then have your machine shop remove the spark plug when they are doing any other machine work...just a thought...
andy, i agree but am tired of doing work on friends bike and it blowing up. tried to get the plug out today to no avail but took side cover off and turned stator with a spanner and motor turned easily.if i can get the broken plug out the motor is going in his frame as is.
I can understand that.... BUT....It may still be easier to remove the head... get the plug out and refit the head with a new head gasket...
and if the plug comes out without removing head bolt the motor in, refit the elelectrics and send him on his way.no money only friendship in this and after many days of work you get tired.i am tired.
I wouldnt use an air chisel... very little control. If you have a small (12mm wide or less) cold chisel try getting the plug to unscrew or break the initial seal using that and a good sized hammer.. less swinging force... higher initial impact through mass. You want to get the angle reasonably low so more force is trying to undo it rather than hitting parallel. Heat will help... a gas torch on the area.. Allow should expand quicker than the plug... concentrate the heat on the head... not on the plug remains. Good luck with it.
For a 2 cylinder I would agree with @Andych that the head coming off is probably the easiest way. It seems like more work but I know that trying to work around that perception can often be more work... I understand your feelings about it though, for sure. Hopefully you can find a way.
