"I just picked up a 1979 Honda PA 50 in very good shape, just rehabbed and overhauled, but I'm concerned about the pick up. This thing is slow and really struggles with the hills. I think I've been over 20 MPH flying down a hill, but can barely do 20 on a straight a way. Is this normal for this model? Anything I can do to increase the speed or pick up? Any follow up would be appreciated.<br>Thanks."