Quote Originally Posted by oliver13 View Post
If anyone has any tips for radiusing the compression side of the transfer port I'd be grateful. I use a 6mm drill welded to a length of welding rod in a battery drill. It just takes a second but would be very easy to go wrong, if anyone's come up with something better I'd be grateful if you would share?
I used a length of aquarium tubing taped to a piece of rod for stiffness. Put in a drill bit that was snug in the tubing, and rotated by hand. A bit wobbly but no matter as just knocking off the sharp edge. I followed this up with a dremel stone in the same tube for a bit of smoothness.
Cleaned up TP port, and .125 size still got me 16fpe, so I don't think there is much to be gained by a mirror smooth TP.

It seems as if I have read this in regards to porting 2 stroke engines also as I was doing an RD350. Biggest areas of concern were said to be sharp edges at castings.