I have sent Patrick pictures that he has agreed to post for me.
As you will see from the pictures this modification was quite an undertaking. The person that did the brazing was certainly extremly skilled. It appears that the cylinders were first bored out for a sleeve then shortened and sleeve was pressed in against a shoulder, which is the dark area at top of cylinder bore shown in picture, and flange installed all brazing done and the final machining.
I did find out fom another racer from San Diego, Ca., Jim McMurren, who was close friends with Cal Rayburn that these rods were actually machined from scratch and not shortened stock rods as most others did. Jim said Leonard actually hired the machinist and purchased equipment for him to work with.
One problem I did not think of before inspecting these parts is the neccessity of offseting the threaded o-ring collars on the lifter bosses so the lower spring covers line up. Again you can see this mod in the pictures. Also the main bearing on the timing side has been modified to use the same size bearing as drive side. Crankcase bored out and steel sleeve installed. Timing side crank pinion shaft converted to press-in instead of taper w/nut. I believe the very early XR's used this style shaft.
I am in the process of trying to find out how this motor would have been raced, if at all, ie: RR or dirttrack, or just a dyno mule. We intend to build it into a complete bike. I am in the process of trying to contact Mel Lacher who rode for Andres in the time period this was built. Mel was a very fast Ascot specialist so I'm hoping the motor was used in a dirttacker, a lot easier and cheaper to build than a KRTT.
I will keep you all informed with updates as I proceed.