Does anyone know the torque specification for the crankcase nuts on the left side of a 250 cc (M91) engine? I can't seem to find this info anywhere. If not an "official" spec, then I would at least appreciate a reasonable figure to use in the opinion of the experts here. Please also indicate if this torque would be the same for the single recessed hex-head bolt at the front of the crankcase. Many thanks!

M 8 bolt 16 ft lbs M6 7 ft lbs

Many thanks for the reply. When you refer to M8 and M6 bolts, what is that referring to, exactly with regard to the crankcase nuts? What I have here are a bunch of 10 mm nuts with lock washers, and then one allen/hex-type bolt at the front of the engine. According to a chart I found, M8 bolts would equate to a 13mm wrench size. Neither of my fasteners are this size. Please clarify which number refers to which fastener on the engine.

Also, how is it that the M8 crankcase bolt has a higher torque setting than the 8 mm cylinder head nuts, which are spec'd at 14 ft pounds per the Chilton's manual? (I realize the larger head nuts have a 25 ft lb torque). I've already snapped one of the crankcase studs previously, and want to get it right this time! Thanks.