If you've changed your fork seals and still have some leakage, the SealMate Fork Seal Cleaner might just take care of the problem. Commonly used on dirt bikes, it's also been reported to work well on Vulcans. There's a video showing how it works:
Available at Amazon and likely other bike shops near you.
Note: If you do find that you need to replace your fork seals, there's a great video on Youtube from Delboy's Garage.