That's how it usually works.
When I was riding the Chicago leg of Relay Rally I about 3 weeks after getting my 550 on the road, it started running like absolute crap. Didn't want to rev, wouldn't go over 45 mph, ran through a whole tank of gas in about 35 miles.
It took me two days of looking to discover that the tiny nut that attaches the condenser to the 1-3 points had worked loose and was creating an intermittent fault. 30 seconds with a tiny wrench and it ran like a champ for the rest of the time I owned it, including the 6 day ride with the Michigan team.