Thanks so much for the advice, I'll redo the break in this way. I have a question on the cylinder head. Like the hasty fool I am, I changed the glow plug because the engine would not idle without the battery attached. I managed to strip out the glow plug threads in my haste to change it. Question now is, I went to get a replacement head, but it was from the TT gp .61. It wouldn't fit! it was just under a mm wider, but everything else was the same size. I tried it with a piston liner for the gp .61, and it still wouldn't fit. What is going on here? i am assuming that both engines are using the same sleeve and piston, even though the parts numbers are different, as the gp uses the same body as the pro. I guess the major differences would be different carburetors and bushings instead of ball bearings. This has me stumped. Anyway, the dealer had to backorder the head, and it should arrive by the beginning of next month. Any comments on the different sized head?