Alexander,


Your engine is probably a tapered-bore ABN design.

If it is, [link=http://www.rcuniverse.com/forum/m_1850473/anchors_1850473/mpage_1/key_tapered%252Dbore%252Cbreak%252Din/anchor/tm.htm#1850473]this thread[/link] illustrates the correct break-in procedure.

I have heard of some older versions of this engine, that are lapped meehanite piston designs, so please verify that your engine isn't one.
The correct procedure for a tapered-bore engine, will turn a lapped piston engine to junk.
This is also correct vice-versa, to a lesser degree.

So before you proceed, verify the type of engine that you have.