Now that I have my Beemer (old but golden K-75 RT) to ride, guilt in me said I really needed to fire up the wife's 2000 EN500 C-5 (Vulcan LTD) so that we could go riding together.
I knew those Keihin carbs respond poorly to long periods of not running. So I bought a set of jets (from CarbJetKits ™ [carbjetkits.com]) and surprised myself how easily I cleaned up all the parts, replaced the pilot and main jets and added a spacer that came with the kit to the main needles. BY FAR the biggest pain in the ass is getting the pair back in place, both the squeeze past the manifolds and getting the throttle cables hooked back on.
Battery charge, oil change and she fired right up!
However, the engine still bogs when you get to about a quarter throttle, and if you insist by further opening the throttle, acceleration is sluggish, punctuated by the occasional surge as a hint to how quick the bike should be.
Everything is stock. I have the petcock on PRI so I know the carbs are getting fuel. What to try next? Could the air filter be so dirty she can't breathe? (Will look at that tomorrow).
You might try and re-post this question down in the Vulcan 500 section, they may be able to help you better.
How long did you have it running? Was it able to get warmed up? Carbs don't work as well in colder weather (the fuel doesn't atomize as well). So it could be something as simple as just being cold natured. Cold doesn't necessarily have to mean below freezing either! Just being a little cooler out can affect cold running performance.
"8 But God demonstrates his own love for us in this: While we were still sinners, Christ died for us."