U can spray a carb cleaner like Berryman B12 on the areas you suspect are leaking. If the idle goes up or down it is sucking the spray in through a leak. Be cautios not to spray so much that it is getting sucked in the carb intake. You might need to hold it at a fast idle for best results.
2014 Harley Ultra Limited
2013 350 EXC-F (Wife's)
2008 530 EXC-R/2008 Beta Rev4T
2006 950 Adv S/2002 640 Adv/1970 Yamaha RT1