First off a kind hello to the Xs community from Italy
@spungle
Nice bike you have there, but if you don't mind me saying the info about no return valves on the crankcase, d-shaped ports in combination with the recommendation of the use of of a higher lift reasonably short duration Megacycle or web cam profile has been for years on the German forum.
@Jack
Compliments to your nice d ports, don't mind the critics of some people that might not fully comprehend the theory about such (btw very nice looking) d-ports.
I have been using D-ports, where needed, for decades now and with proven track success on Sr/Xt engines (did not find the time for my Xs engines within the last year's due to work) among several other brands (honda, Ktm, Norton, triumph, and among other mod's even DBD34 Goldie's) and makes.
The only thing that remains crucial in doing such work is that the cam should be chosen accordingly to the port properties or better said the port should be shaped according to chosen cam profile spec's (mean flow, maximum increment flow which is not maximum flow and maximum flow lift etc etc).
Kind regards
Christian
Ps: sorry just read it now, spungle, if you don't mind me asking, who welded and how the crank I assume in Germany? Given the fact that the crank and iniin particular the pin is of a higher alloyed
steel it is important to weld it in a certain temperature releasing / inducing mode in order to not brittle out the HAZ.