I too am new to the hobby. And since I am about to break in my second engine I have been following all the break in threads with interest. My engine came with a pipe. So I don't have a choice here. It will be broken in on the pipe.

Here are a few things I have gathered about breaking in a ABC engine from various sources:

1. If supplied, follow manufacturers' instructions. They should know what is best for their product.

2. During initial break in you are primarily breaking in the connecting rod bearings and journals. The piston and liner are not the primary concern during breakin. There is nothing to 'seat' on an ABC piston/liner. The piston/liner will wear itself in during normal operation.

3. You want to break in the engine in it's normal operating temperature range. 230-270 degrees or three quarters to full throttle. Under no circumstances would you want to idle the engine for extended periods. The piston and liner need heat to expand to their proper tolerances. As soon as the engine fires up bring up the RPMs and get the engine to the proper operating temp as fast as you can.

4. Sloppy rich or four-cycling is bad. You will damage your connecting rod and journals. Run moderately rich.

I think all this makes sense to me sofar. I should be ready to break in my engine this weekend. If I left something out please let me know.

Tom