I was lucky enough to have this beautiful little 49cc motor come across my bench this week.
It's got one of the best quality cylinder castings I have ever seen on a Chinadoll with a huge round exhaust port and exceptionally clean fins.
It also has the long curved clutch arm I normally only see on recent motors, but the rest seems like a much older better quality engine.
It has the square head with the tiny 10mm head nuts and the older style, high quality machine grey paint (like the old bridgeport mills had)
Overall it looks to be a much better built engine than you usually see.
The huge exhaust port has me thinking it might be time for me to pick up a porting tool again after all these years since this one looks to be worth the effort even though it's only a 49cc. I recently gained access to a compressor so all I need is a die grinder and a few carbide burrs.
It's been my experience that the older 49's will rev a lot higher than most any 66cc with the better crank balance inherent in the smaller displacement.
With that huge exhaust port, it needs is a bigger intake and some transfer aiming and case-to-cylinder matching and it should really wake it up. Nice thick casting with PLENTY of room for any sane porting makes me think it will be fairly durable too!
Can't wait until it warms up a bit here to slap it on something and see what I get for a baseline!