high pitched click click

[jeepdaddytj]

hey all , just joined the site and just bought my first street legal bike. 1997 xr650l - 18,500 miles yeah it's a lot but it's a nice bike ,,, well so i thought. after riding around and getting it warmed up at an idle it makes an intermitten pop pop crack sound , kinda like a bad plug wire sound but only noticable from the right side of the bike. but get this , shut it off and leave it sit for a minute or so, restart---- sound is gone any ideas