82_xj650

just picked up a sweet 82 maxim 650, runs like a wet dream! only one issue, after she warms up(after 10 miles or so) when stopped it will idle high, between 2500 and 3000 rpms. the rubber between my carbs and my block are dry rotted and cracking. im figureing this to be my problem. they want $200+ for the new rubber, which i dont get i paid less for the rubber on the tires. but is there an easy cheap fix for this? or does anyone know any cheap parts shop? and finally what is the name of that piece of rubber?