Recently my 2009 Grand Vista 250 (2100 miles) has developed a sputter at idle. It sounds as though it is going to stall, but does not quite stall. I have tried adjusting the idle speed and either it idles to high or to low and stalls. Can't seem to get it right. It was time for oil change so I did that and changed the spark plug. Neither of these helped. The bike also revs really high when started from cold and seems to take a while to come down to a "normal" idle. It has not sat much during our mild winter months; rode a few times a month during winter months, so gas should be fine. If anyone has any suggestions, I am willing to try just about anything.