Hi and thank you for your question.
I would like some more information about the symptoms you have experienced.I see from what you have shared there have been some other issues relating to electrics and starting. The questions I am going to ask you now are exactly the same questions I would ask you if you were hypothetically bringing it into my shop for the same problem to be repaired. Under those circumstances, I would ask a question and allow you to answer it before moving on. However, in this forum, that would needlessly delay the process and resolution so I am going to list the questions all at once. That does not diminish the necessity for a complete answer on each question however, so here we go.
First, How many miles are on the bike now?
How long have you owned the bike and how many miles have you put on it?
How many starter relays have you replaced?
How long does the replacement typically last?
What does the bike do or not do that lets you know the starter relay has failed?
Is it always the same symptom indicating it has failed?
Why was the starter replaced and when chronologically and mileage wise was it replaced?
Are the replacement relays OEM Yamaha new parts?
Were any of these failures or parts replacements concurrent with other failures?
How long has it been since the bike was serviced? Specifically valves adjusted and carbs synced?
Are there any non stock parts or modifications to the bike?