My GL650 Silverwing sat up for 3mo. It was running good when put up. Started and ran great until you got to 4000rpm. with a load on it. Then it ran like crap. My machanic has been through the whole bike and tests that can be done - we think! Still doing it. Anyone had this problem before? If we can find it, I will have almost a new bike. It has 28,000 mi. on it. Thanks.