My '86 Honda NC50 Express would not start. Brand new plug with less than two hours on it. Pulled the plug and the ceramic insulator holding the electrode is cracked 3/4 way up it body( Inside of the plug). The electrode is now off center. No spark because of this. What would cause this to happen? Autolite plug. Old NGK plug is working fine.
Sometimes installing a plug in an awkward place can result in the socket canting and cracking the plug. It doesn't always fail to spark immediately. I will never admit to making such a newbie mistake. If the socket doesn't have a rubber insert, make one with duct tape. Wrap a plug with it, sticky side out, then finish with a wrap of smooth side out. Get to the point, trial and error, where it will just push fit into the socket. The smooth side out means it can be easily removed and reused. You have just made a custom special tool!
2013 Tao tao cy50a 5500 miles unrestricted proper break in & maint, syn oil, opened outer snorkle holes, removed inner snorkle jetted correctly 35W halogens!
I've used padded spark Plug sockets for 55 years now. This happened while running as it died just after a wide open throttle run. I contacted AUTOLITE and they say it was over tightened in the head. They asked if I used a torque wrench,which I did not.No warranty. I've broken the outside porcelain insulators over the years,but never the inner ceramic one. New NGK's are on the way.