Big Island Harley Davidson in Kailua- Kona
Unfortunately is on the other side of the island .Call them and they might have ways to get a bike over to you.
I've rented from Big Island H-D mentioned by DandSPro, but on Maui I've used the folks at the following link. Picked up a bike in Lahaina. I'm pretty sure they have a location on the big island. Aloha!