I was tapping out a bolt hole in my brothers YZ 450 to helicoil it and while treading the hole, the bottom broke through. THere were two pieces of metal from the crankcase cover that fell right on the lip of some gears. I was able to get the bigger of the two pieces, but a small piece about the size of an "a" maby a little smaller fell down into the cases. What should I do? Could I use a small vacum with a hose on it to try and find the piece? Anything besides splitting the cases. Advice?