Greetings, I don't post often over here in airhead land though I'm pretty active on the F650GS Dakar thread. I searched around for similar threads before deciding to start a new one - if there's a better place for this please let me know. A few months ago the engine started stumbling, missing, backfiring, while riding at freeway speeds, gradually but inconsistently getting worse over time - bike would idle fine in my driveway, and rev up in neutral, but take it out and run it under load at city street speeds and the problems would crop up til it stalled basically. I adjusted the points and then the bike wouldn't even idle. @Motopsychoman who lives nearby came and helped me do some diagnostics and adjustments, including setting the timing and adjusting/syncing the carbs with his Katdash Harmonzier. The carbs weren't super far off to begin with but the timing needed adjusting and we got it to idle and rev smooth, but I didn't have time for a test ride that day. Since then, no good - it won't even start and hold an idle. Here's what has been done so far: First I eliminated the possibility of fuel/carb issues. The carbs are somewhat recently overhauled and have all the correct parts and needle clip position as spec'd by Bing. There were no blockages or float issues. These are the smaller slide carbs mind you. Air filter appears fine. Torqued heads and set valve clearances to .004" intake and .008" exhaust Set points gap to .016" and set timing. Norris points were new less than 1000 miles ago, the gap had closed up a bit due to initial wear of the rub block, maybe down to .012"? Advance unit had the springs replaced when the new points went in. The bob weights spin out and retract, full advance was visible in the timing window (slightly double image, I recall) Checked and cleaned all contacts at condenser, points, coils with DeOxit. I don't think there are any pinched wires or bad connections, but I suppose I could check all this again. Static multimeter/resistance test of condenser and coils - they seem fine? But I am suspicious of these... 5kOhm NGK leads are relatively new, look to be in good shape, measure within spec NGK BP6ES plugs are in decent shape, proper gap, though I keep having to clean the carbon off them from the rough running. I have two sets in play, they don't seem to exhibit any difference. Same group of plugs in the bike as before the problem came about. Chokes cables have free play when choke is off Throttle cable free play adjusted New battery as of April Nothing else that I can think of is different from when the bike was running fine. However at some point working on the bike I realized the problem was likely my negative battery connection at the engine - the breather bolt hole is 90% stripped, turns out, and the cable terminal wasn't properly held fast to the gearbox. This would explain the intermittent nature of the problem. And in trying to sort this out, I'd have the ground disconnected at the battery end for front cover removal etc. and afterwards the problem would sometimes go away for a bit - clearly the ground connection to the engine was getting bumped around. But when the bike would run OK, this also may have fooled me into thinking I'd been fixing the problem by other means. So this week I made an adapter to bolt the ground to the gearbox cover, thinking that would cure my ills. No dice. (by the way, I could be making more of these, if people are interested...) In daylight the spark appears weak, smallish and more yellow than blue. Just checked in the dark and now I can't be sure, I'm not an expert on spark appearance. Problem seems to affect both sides equally, not limited to one side running poorly. Bad condenser? Bad coils? I'm stumped. Had the battery charged up to 12.9V in one attempt to start today, while the motor was running I measured ~13.4V but it was moving around due to the rough running, and I doubt I was revving it much past 3000. So I don't necessarily suspect the alternator or charging system. I am considering new coils and electronic ignition from Rick Jones anyway, but don't want to start replacing stuff willy-nilly - harder to learn from what went wrong if you use a shotgun approach.