If you have the CR500 mod for the Pilot bottom end, I found a hose "set up" that works well with CR500 Pilot head. If you have the CR500 top end and the head didnt come from ATV Racing (they modify the head for one 3/4 outlet), then you will need to convert the two 5/8 hoses to one 3/4 hose. I found this kit to work well. It allows you good access to the spark plug and is neatly tucked in front of the radiator, see pics. Heres a link to the kit. The kit says its for a CR125 but it fits the CR500 as well.
http://sharkshifter.com/zc/index.php?ma ... e3f5cd0f37 .