Simon,
Just checked the length of the M8 bolts that join the crankcases top to bottom around the main brgs, and they're about 10mm shy of your measurement - not wishing to teach egg sucking, but I assume that you're measuring from under the bolt head to bolt end ?
Only other place that I can recall using M8 is engine mounts, but 125 is still too long - longest bolts go into the lower crankcase from either side, but they're critical on length to avoid damaging the casting.