My stock '03 B12 has never wanted to start or idle when cold, without the choke halfway on. (Even if it's 95 degrees outside) Just had a local shop do my 7500 mi. valve adjust. and had them synch the carbs while they were at it. Suddenly, the bike starts and idles, albeit slowly, with no choke at all. I didn't expect this result. I assume the carbs were way out of synch?