Hi Jethro,
I just had to do some work on a Cox with a Kohler motor on it, great motor but what a pig of a thing to get an oil filter for it.
I also love rebuilding the old Victa 24's, think I still have 7 of them here, hell of a lot of work getting them back into service but the satisfaction of keeping the going is worth it.
The Masports seem to be ok with the bigger 4 strokes, but shouldn't be too hard to fit a 2 stroke to them. Just remember if you fit a PT to anything like that you must add up to 2 kg to the crankshaft, that turns them into a mean machine