timing/ starting question

[bluecycle3]

78 R80/7 31k carbs rebuilt, new points, diode board, valves set, points gap set, was running fine, now on cold mornings it won't start, starts up at night when the temp has come up to around 50, bike seems to run a little rough on the bottom end but runs good everywhere else. is this a timing issue? which way do i need to go? advance or retard? any advice appreciated. thanks greg

[boxermaf]

IF it is temp-related, I would hazard a guess that either the enricher circuit or idle jet isn't quite right in one or both carbs or the air mixture is set too lean - OR - are you still running an old coil and plug wires ? Might be a crack/intermittent connection in there..

[lostboy]

Did you swap the chokes from left to right?

[bikerfish1100]

just went thru this with the R80g/s my g/f just bought. ran nice, started like crap. all specs checked ok.
turns out that 1 carb, recently rebuilt by p.o., had the choke assembled backwards. made one carb rich with choke on, but wrong one ran lea,. then reverse that with choke off- wrong ran rich, correct one did as it should.
look for a dimple on the center-post on the choke shaft (brass part)- both dimples should be on air intake side of carb, not motor side. her left carb's dimple was reversed.
runs & starts great now.
easy enough to check the timing- but timing should not be a temp dependent situation. check with a good timing light, but i'm guessing carbs.