"Best" BILT cover from Cycle Gear; unless you intend to pack it, I'd recommend a LARGE size.
Absolutely guaranteed by Cycle Gear; exchanges/refunds without trauma.
Cover shredded in tornado or hurricane? Probably not warrantied under these, "Acts of God." Otherwise, satisfaction guaranteed.
Ask your "associate" about exchange/replacement/refund policy.
If you want to go, "first class," consider SPEEDWAY shelters. A medium will cover a KLR650, but a large would be more convenient and useful. Basically, a steel tubular frame provides a skeletal base for a fabric cover; a mini-garage, more-or-less (I use one).
Will post a picture, or . . . check out the manufacturer's website:
CAVEAT: I did NOT receive one of the lovely ladies shown on the website with my shelter.
Here's a trade show demo:
My experience: SPEEDWAY shelters work as advertised. (I now have a later model than shown in the video clip; has convex steel tubing on "roof" as a countermeasure to snow loading; also, fabric durability and waterproofing improved.)