I just got a box with all my old (broken) engine stuff, it was all examened by my sponsor in the use for devellopment/comparing their engine.If I could build up something for trainig, spare or as a rain engine.
I found the case of my old RB Xenon-R (Sirio based), I know it has runned just 6 or 7 liters before the rod broke. The crankpin was still OK end in good size and no play on the bearings so this must be a good start.
A good looking sleeve of a JP R01 and a fitting piston with a R7 rod must make a fit.
RB dos have some differences comparing standard Nova based engines and one of them is the location pin. A small cut on the opposite side is simple to do.
The hole in the case for the sleeve is 19.4mm while the JP sleeve is 19.5mm, I fixed an adapter to mount the sleeve in my drill station and with a piece of sandpaper I could grind it down to 19.4mm
When fitted it was clear the sleeve was sitting to low so from a 0.5mm thick plate aluminium I made a ring for under the sleeve which did set the sleeve almost to the right height looking through the exhaust.
RB has a crankpin of 5.02mm so a R7 rod with a 5mm hole will not fit. I have a dremel 5mm diamond grinding bit I have used before to do this job. Now it fits like a glove.
In the box also some heads made by my sponsor to fit Novarossi engines. It has an in one piece combustion chamber for a maximum cooling. It did not work that good because the chamber was to small and to much head clearance needed to be used. With a 10mm drill I could make it a tiny bit wider and straighter in shape to get more volume.
While I was busy I just drilled some holes to make it lighter, I did go from 70 gram to 65 gram, not that much and I think most racers do not notice that.
With a piece of solder setted the head clearance to 0.7mm to start with and mounted it all togeather.
OK, the stroke of the crankshaft does not fit the stroke the P/S set needs but 0.1mm difference (16.7 / 16.8) is not a huge difference
Now just to mount a clutch and give it a try.