Heh heh ... yeah, that tiny screw seems a little ridiculous to me as well. They are almost small enough to work on a pair of sunglasses. I did not notice that it was really all that louder without the baffles, but I am thinking it is basically like a hot day in Vegas where it is 120 degrees. It really doesn't feel all that different from 110, both just feel blazingly oppressively hot. This engine is loud, period. I did notice a seeming loss of bottom end though. Perhaps when I install a muffler (using both ports) it will achieve the same effect?
I have thought about using that little plug, but I first have to try my luck going up that hill (Colima) on my route to work. I will probably test that today. I will make sure to bring along some channel locks so as to try the hill with only one exhaust port as well, but if it goes strong up that hill, then my theory probably stands where the one time I did go up that hill it did not have as much power. It definately did not have anything to do with stops and whatnot either. I have been up that hill three times now. The first time there were no stops and I was doing almost 40. The second time I hit all three lights and came to a complete stop each time, but was still doing 35 at the top. The third time I hit no lights, and was pedaling hard and hitting 30. Letting off of the pedals caused the bike to slow. I do vaguely remember noticing an improvement in low end accelleration, but I chalked it up to the engine breaking in. It sure does feel flat and powerless up to 15mph now though.
Okay, so the scorch marks were definately brown and no blued metal of any kind. So they must have been caused by the blocked exhaust/rich mixture. I did not think to try scratching it off with a fingernail. Not gonna try now! The glazing at the one skirt was not colored at all, I could only see that the horizontal machine pattern was rubbed away. There was no glazing on the cylinder wall though.
I also gotta read up on the thing kerf experienced where the air filter kept filling up with oil. I am thinking it was caused by the blocked exhaust, but it happened to me as well.