MRT1750, a couple of other ways to tell if your's is a 105 instead of a 102. . first off . .BOTH exhaust ports will show that the piston is about .5-.75 mm (.020-.030") below the exhaust port. This is because the 105 crankshaft is actually a 110 crankshaft, with a 1mm longer stroke, and the 102 crankshafts and crankcases were set up to have the piston come to dead even withthe bottom of the exhaust port, or about .010" below it. The second way is to pull a jug and see if there is ahole in the counterweight. If so, it's a 110 crankshaft, because the crankshaft design was changed to facilitate balancing the 110, which have a lighter piston. It does not cause undue imbalance in a 105, since the pistons basically self-cancel when they move, but it IS a design difference.

I've enclosed a pic of the 4 crankshaft designs that BME has used. . the 110 crankshaft is in the middle, rear, and the 102 crankshaft is on the left. ON the right is the first edition 102 crank and at the bottom is the old 5.8 crank assembly.

Hope this helps