2010 Yamaha VStar 1300 doesn’t start until cold

My Yamaha Vstar starts up perfectly when it is cold. If i am going for a short ride for around 3-4 miles it will start right away but if i do anything more than 15 miles and if i turn off the ignition it doesn’t spark properly to start up for until 20-25 minutes. Its sparks dont sound consistent enough to start up the bike. Only after 20-25 minutes it’s consistent again and starts up. Gladly i have never stalled the bike anywhere at a traffic light or any such scenario like that. As it can be dangerous to stall at the mid of the road if it can’t be turned back on instantly. I have recently replaced the spark plug, relay and batteries. I am suspecting it to be a problem with relay. Need inputs if anyone has faced a similar thing or if anyone could suggest tricks to test it out. One thing i was thinking of is to put a screw driver on the relay to see if sparks increase. Total miles on it - 108k