I'm going to be doing the 1,000 mile oil change on my '09 Street Glide in a day or two. Here at the air base in S. Korea, there aren't many options for oil to use, but to my surprise, they do have Royal Purple Max-cycle. The Royal Purple web site recommends 20W50 in the engine and 10W30 in the primary and the tranny of Harley Twin Cams. The 10W30 for motorcycles isn't available here, but I can get 10W40. Do you think this will be good to use in the primary and the tranny? Have any of you used the Royal Purple oil? I'd appreciate any advice.