I acquired a 1999 Honda XR70 and was changing the oil for the first time. I don't have a manual yet and I took off the wrong bolt on the bottom of the crankcase. When I removed the bolt, a metal tube with several holes in it came out. I replaced it (making sure that I put it back the way it came out) and then removed the correct bolt to drain the oil. I replaced the oil, but now when I start it, it makes a funny pinging sound from the crankcase. Any ideas? Thanks in advance! P.S. Yes, I am ordering a manual!!