I have been tracking down a couple of lingering problems with my bike; inconsistent idling problems and a jumpy tach. The idle would drop to next to 0 and eventually sputter out, but only occasionally. I posted on this before and I have been trying to track down a possible vacuum leak. I also had the tach needle doing a little dance around 4000 RPM. Never got terrible, but it was definitely noticeable. Well, both problems reared on Friday afternoon. So I was all set to tear into the bike on Saturday morning. I figured I would go back to square one and try to take a look at everything, compression, spark, air, and fuel. When I went to remove the left side rear spark plug, it pulled right out. The thread section broke clean off! The ceramic insulator and electrode was in my hand, the threads were stuck in the cylinder. After removal using the biggest screw extractor I had, being very careful not to create metal shavings, I replaced the plug. Just for good measure, I replaced all of the plugs. Even though I read about how not to get in this situation, I obviously over torqued the plug when I put it back in the last time. I had them out a couple of times recently, while checking out other issues I had been having. It definitely seemed to slip while doing the quarter turn past snug torque. Now I know that it was the housing breaking loose!
Stupid mistake, and it cost me a bunch of time and aggravation. Live and learn. Not a terribly expensive lesson ($12 for the new plugs), but one I'll not soon forget. My @$$ is a little sore from me kicking myself, but that will pass!
Well the jumpy tach problem disappeared, and so far the bike has been idling right on the money! I'm guessing that the vibration when the bike was in a certain range, was causing an intermittent bad connection, which was causing the tach to get squirrely. I am also guessing that I wasn't getting a reliable spark due to the problem with the ground, so the engine was running rough at idle as a result.
I hope that this makes sense! I am hoping that the seemingly never ending search for the elusive vacuum leak has actually ended! The bike is an '89, and I did expect to have to work on it, but between the age of the bike, and the fact that I am new at wrenching, it seems like that's all I ever do. As much as I am liking tinkering, I like riding better! I have had about 300 problem free miles since Saturday morning (aside from the ladders of course!). I'm truly hopeful that the trend will continue. (no more ladders thanks, just the problem free riding!!)