82 XS650 weird plugs torque

[Mark Arnold]

The 82 was running just fine then I decide to stick new plugs in her. Took out the socket and backed out the first and thought 'that was pretty loose', huh. The second was the same. I proceeded to reinstall the new ones. Torqued them down and tried to fire it up... nothing. So I backed them out, finger tightened them back in and it ran fine. So I then incrementally tightened them down, not to full torque but close. It's running fine at the moment. Am I missing something here? I've not run across this before. Coil not enough power under high compression? Thoughts?

 

[retiredgentleman]

Changing the plugs should have no effect on starting ability of the engine (unless the previous plugs were fouled). Since you moved the spark plug wires around, have a look at the connections on both ends of the plug wires. Maybe you have loose connections or worn out wires.

I always install my spark plugs with my fingers only, so that there is no chance of cross threading. Once they are fully turned in, I use the torque wrench at 14 ft-lbs.

 

[Mark Arnold]

I thought I might have loosened up a connection too. I plugged the wire on each plug outside the jug to see if I had spark. I did. I always finger tighten plugs as well. Strange.

 

[pamcopete]

Mark,

It's possible that the porcelain insulator is cracked which would allow the plug to arc through the crack, or the connection inside the porcelain is now broken so sometimes it works and sometimes it doesn't.

If true, you will find out on the side of the road when the porcelain insulator separates completely. If it was me, I would replace the plugs with new. Use Autolite #63's. Great plug at a low cost.

 

[Grinder]

Are the 63's hotter than a BP7ES? Most cross charts I've seen cross the 63 to a BP6ES.