I stripped two bolt holes on the engine of my Yamaha V Twin. This happened while I was replacing the side cover. Both bolts are 6 mm metric (6 x 1) The 'meat' where the bolts go into the engine casing are rather thin, so I am not entirely comfortable drilling these holes to the next size (8 mm) and re threading the holes.
On a test today with some scrap aluminium, I first drilled and tapped holes of 6 mm; then stripped them and then re threaded them to 1/4 x 20 pitch. While the threads were not perfect; the bolts held to twice the torque specified for the side covers (20 ft pounds).
Before I re thread the holes on the engine casing; I need the assurance that this repair will be ok.
On a test today with some scrap aluminium, I first drilled and tapped holes of 6 mm; then stripped them and then re threaded them to 1/4 x 20 pitch. While the threads were not perfect; the bolts held to twice the torque specified for the side covers (20 ft pounds).
Before I re thread the holes on the engine casing; I need the assurance that this repair will be ok.
