Thanks AV8TOR.

I guess then the hole doesn't have to be perfectly round? I hadn't thought about the port side of the hole. I would have enlarged it all the way thru.

Another question.

I've done the porting mods on the intake and exhaust ports following the directions for blueprinting the engine and modifying the ports from the 0catch website, but the transfer ports on my Homelite 30cc are different than those pictured on the Old Homelite and New Homelite instructions.

Both transfer ports are divided by an isthsmus so it appears there are 4 transfer ports. This is a fairly new engine, less than a year old. Is the web information out of date? To make mine look like the pictures, I would have to mill out about 3/8" of material the entire height of the port