I have been deferring maintenance on all my bikes lately. The Morini need swing-arm bushings again, the F1 needs wiring, the ST4S needs and oil change and valve check. Then, I notice sputtering from the normally trustworthy CT90. This continues for a week or two, as I become increasingly concerned that the little thing is trying to tell me that it needs some kind of major work, after years of mostly benign neglect.
I am suspicious of the carburettor, and sure enough I look at it on a recent arrival