First off, AAAARRRRGGGGHHHHHH!
Okay, now that I've got that out of the way-
1977 R100S, only 40K, has always run like a champ for the couple of years I've owned it... including starting- I have to use the choke/enricher maybe only 5% of the time I'm starting it.... Until about 3 weeks ago, it started stumbling at speed, so..... checked the gas, completely disassembled and cleaned the carbs, reset valves, swapped spark plug wires, checked the points, etc etc, and nothing worked- after doing all the checks I couldn't even get it restarted....
So, checked the timing and it was off, readjusted the timing and tried to restart.. very, very, very difficult to start.... but after about 20 min of turning it over, she finally started and was actually running very nice. I took it for around a 25 mile jaunt to charge the battery and see how she was doing- it was glorious! She's never run that good! A buddy and I raced all over the county at high speeds, and through town in stop and go traffic, and she didn't miss a beat! Not a single stumble, just flat-out joy, and she idled perfectly in between hauling ass!
I came home and had some dinner and let the bike rest for an hour or so, then took her on another jaunt up the canyon, once again- joyous! Just the touch of my finger to the starter and she would leap to life, and idle perfectly- then accelerate without any hangups. Went to bed very happy that night.
Next morning- tried to start her up and it took a little prodding, I actually had to use the choke... But before I could even go a block , she sputtered, bucked and stalled out and would not start back up... Pushed it back to the garage, and while fiddling with her/turning it over I got her to start up again, and once again, she idled very nicely (with choke off), but just the touch of the throttle she died again.........
So to sum up- she runs perfectly when she's warm... but when cold, she's impossible to start.... what am I missing??????