I have an old Royal 25 that was in pretty bad shape. So, I went on Ebay and to my surprise I found a guy selling crank cases and piston / sleeves for the engine. I bought them, they arrived, new in package. I took all the parts out of the old crank case, cleaned the gunk off and went to reassemble the engine with the new parts.

My efforts were stymied when it came time to install the carb and nose bearing. The front bearing from the original engine had an outer diameter of 17mm the new crank case has a much smaller opening (I think it was 13 or 14mm). The original thrust washer is bigger too. Also, the original carb fits in a 10mm hole in the crank case, but the new case is like 6.5mm.

I guess they updated the design along the way. I've considered drilling out the case to mount the carb, but I need a replacement bearing for the nose. Any idea where I could find that part?

Thanks.
Jason