QuestionI have a 2005 GL1800 when I start the bike it idel around 1000 rpms but drops to around 450-500 rpms
AnswerDanny, it is my brand, but as you may have noticed, I don't claim GW knowledge..... 900 lb, Fuel injected motorcycles are more car than bike, IMHO.
go here and good luck
http://www.ridersrally.com/forum/viewtopic.php?t=20392&highlight=idle
sounds like it could be IAC, sticking injectors or ECM issues.
Bill Silver