This one ought to be fun. It's the last of my "fix 'er up" quests since I got it. There has been this whomping sound from the engine, accompanied by bucking. It happens at any speed in any gear, but only if the RPMs are between 1300-1700. I first suspected something to do with the clutch assembly, but if it's in neutral and I rev it up, as it falls down, it makes the "whomping" noise as well once it hits that mid-1000's spot. As I said, it happens in neutral or in any gear, so I'm suspecting engine issues. Also, the lower the gear, the harder the bucking is. 1st gear feels like a rodeo and 5th gear is almost unnoticeable. Ideas?