Having a stripped bolt will cause the engine to suck air at the cap and cause the engine to run lean..It can also cause errosion at the cap and cylinder lip...........One of the bolts on my cylinder head decided to strip.
I road my motorized bicycle and realized it wants to bog down and wouldn't idle so it stalled. The max speed just didn't want to go over 20mph or so, so that's when I checked and found a stripped cylinder head bolt.
I attempted to ride it another 3 miles to get home and while it is bad for the engine if done continuously, 3 miles should not have been enough to be harmful in the long run. So I hope nothing happened to my engine as a result of my terrible decisions and it does look like nothing really happened because once I got home, I pulled the starter and had the engine revv a little when giving it throttle and also pull me. So as you can see, it works and starts up while giving it throttle so I would assume nothing bad happened cylinder/piston wise, so it's not a major concern right now. I did peddle quite a bit to help it and turned the engine off tree times on stops on my 3 mile trip home from when 1 of the cylinder head bolts' stripped.
What is the best way to repair it?
Also this is what the plug looked like when I took it when the engine stalled on me (So yes, when I didn't ride it home yet. The beginning of the 3 miles):
Does this greyish color indicate a perfect mixture?
Something tells me you got an engine kit with cylinder head bolts that are too short....The hreads must stick atleast 2-3 threads through the hole...you can see this when the flywheel and clutch arent installed...The head on my 5 port cag loosened twice and stripped once because of thbeing too short.............
the only way to fix it is to get a tap thats the next size up and use heavier duty bolts..............Use loctite too......The plug looks like a descent burn...maybe a tad rich but thats ok because come winter the air will become cooler and drier aswell as thirstier so itll most likely be perfectly jetted to 60 degrees.......Good Luck