SrTelemaster150

Since you are not re-using the bearings you can use a puller & a bearing adaptor.

I wouldn't try to remove the aluminum in the bore W/abrasives. Perhaps Kroil would loosen it up. There are also chemicals for removing metal fouling from rifle bores that might work. The chrome plating in the bores should be impervious to most chemicals.

Instal the front bearing 1st to guide the crank as you seat the rear bearing.

Freeze the crank, warm the middle bearing to 300°F & slip it on. use a small brass or aluminum punch around the inner race to assure the bearing is seated. Freeze the crank/bearing.

Freeze the front bearing, heat the case to 300°F & slip the bearing in. Use your small soft metal puch around the outer race to assure the bearing is seated. Immediately remove the crank/rear bearing from the freezer & slip it into the still warm case. Seat the rear bearing before the temperatures normalize. Use the small brass or aluminum punch around the outer race to assure the rear bearing is seated.

Clear paint on the cases is likely to yellow or discolor. Use VHT flat aluminum engine paint. Harley Davidson flat aliminum case paint is the best.