I just bought a 2015 Goldwing GL1800 and had it trike, by Motor Trike. It has 600 miles on it. Gas Milage is very bad at 24 mpg. I we expecting much better. Dealer says nothing they can do, it could improve after broken in more. We have friends who have GW trikes and getting 35-40. Any suggestions for this first time GW owner?