A couple of small updates on the bike:
1) I love this thing. I did a couple hundred miles of continuous twisties around Mt. St. Helens as a final ride of the summer this weekend. I'm no fan of the tires I chose; I especially don't trust the rear. But I'm comfortable enough to take the bike over until there's no chicken strip left, at least on the right roads. I'm just careful about inputs when entering and exiting corners. Next year will be bt45's.
2) The jetting is still finicky. I started getting smoke on hard accelleration or revving, in what seemed to be mid to full throttle. It pulled just fine and was very, very responsive. I pulled the plugs: three were very sooty black, one suspiciously lean. Appearance was rich, not oil fouling, and I get very little blow by from the crankcase hose, so I don't think it's oil smoke. Appears to be black smoke/rich plugs. All idle mix screws were 2 turns out, all needles even (2nd from top, which I believe is stock for 550f 069a carbs), 100 mains, floats even at 22mm, uni oem style drop in filter, stock airbox, stock headers, mac muffler.
First I figured the floats must be uneven, like they must be saturated or have variance in bouyance, so I took an extra set of carb bowls, tapped them to add hose barbs, and measured the float height externally - all levels were about 2mm below the lip of the float bowl, which I understand is correct. Returned the mains to 98 (had 100's) - still black smoke, but now didn't pull as hard, and removing airbox made it barely run... which sounds lean??? Tried richening the needles/midrange, but that just made it dog like the choke was on. Basically just tried changing things around. I returned to where I was (stock needle position, 100 mains) and tried varying the muffler - the mac exhaust has a circuitous baffle and doesn't sound particularly good, so I took Paulages' advice and cut the existing baffle out, made a tube out of perforated steel sheet, joined the baffle caps to the perforated tube, and packed it with household insulation. It certainly sounds better, and it's not smoking rich. So... the culprit was the mac muffler? I'll be keeping an eye on the exhaust and the plugs to see where to go next.
3) I'm hoping to make time this winter to run external oil lines from the right case plug up to the head. It drives me nuts to have a light oil leak at the cylinder head, still.
4) I need to make a full separate post, but in the spring I built my own electronically controlled ignition for the 550, based on an arduino, a hall effect sensor at the crank, and a custom coil driver circuit. It allowed for custom advance curves, however you'd like, and constant dwell through the revs. It was an incredible amount of effort, and yes, it worked! (Though I'd want to refine it alot before offering it as a DIY project for anyone) I also made an automatic idle control using a stepper motor mounted to the carb rack, which adjusted idle based on engine temperature. Again, this would need refinement before putting it out there, but it also worked. There was also a computer driven tachometer that integrated with the ignition controller. I'll make a post detailing all of this sooner or later!
