I was aided in setting the timing on my BN2 by a Norman Nock article in his Tech Talk book. He lists the following timing measurements for stock diameter crankshafts: 100-4, 6 degrees before TDC, 5/16 inch on the pulley. 100-6, 6 degrees, 3/8 inch. Mk I, 5 degrees, 5/16. Mk II & Mk III, 12 degrees, 3/4 inch (Dave - good guesstimate). I believe the 100M with the advanced curve is 14 degrees but am trying to confirm that and will interpolate from the 5/16. Mike