Endless chain used on both Rebel or Nighthawk? THink this NH is a late 90s model? Bike/chain has about 10k miles, not terrible looking, was considering a good cleaning/lubing. The bike WONT see much ride time and none out of town. If cleaning, is is OK to gunk the chain on the bike and then hose it off, then blow it dry and lube?
Check to be sure none of the O-rings are missing or cracked, and all the links move freely. If there are, replace the chain. Many use a rag dampened with kerosene (lamp oil) or diesel fuel and held against the chain while it is rotated by hand. Continue until the rag is clean, wipe dry with a clean rag, and lube it. Wax or Teflon based lube sprays don't attract road grit like some lubes. I've used Liquid Performance chain lube with very good results.
Here's one review: Liquid Performance Chain Lube
Type: Spray Liquid
Cost: Very Low
Fling-off: Very Low
Sticky Factor: Low
I couldn't find any reference to using Gunk engine cleaner on a chain, and would be concerned about possibly damaging the O-rings. I wouldn't use high pressure water or air on the chain if you decide to use Gunk.
Keepin' all the left over parts. Gonna use 'em to build another bike!
Don't know about the Nighthawk, but the Rebel had OEM O-ring chain with a riveted master link (as you say, endless). I've always used clip-on master links when replacing the chain. They come with lube and O-rings and are much easier to install IMO. If you look closely between the two (inner and outer) links, there should be some rubber showing.
The only thing that keeps me from getting a Nighthawk 250 is the front (drum) brake. Not quite as good IMO as a disc. I'm probably older than you are.