Starters have a pretty hard life and maintenance of the starter is often patchy at best, so if the starter on your Yamaha is "starting(!)" to fail, then a rebuild may be the most cost effective way to get it back to full reliability.
Other parts that may be of interest:
36Y1551201
36Y1552101
2H71553100
36Y1558001
9361517125
36Y1551701
12R1552400
4H71615501
36Y1551900
9131608016
9131708016
90387201L2
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