When my MK II SQ 4 crankshaft decided to part ways with one connecting rod, the rod managed to reduce the associated piston to bits of rubble.
The P.O. claims to have only ridden this bike 2,000 miles since he "overhauled" the engine back in the mid-90's. He even provided a DraganFly invoice for parts, including pistons. Sure enough, the remaining 3 pistons do look just like new. So, I ordered just a single piston from Dragan (.20 over to match the others).
Today, when I gave a close examination of the piston I find its design is considerably different from the ones they were supposedly selling in the 90's. The new piston doesn't have the diagonal slots cut in the upper area, AND, it doesn't have an arrow on top showing direction of installation:
The one with rod attached is the earlier piston. I can't imagine that these pistons would weight anywhere close to the same, but can't check until I get the rod out of the first piston.
1) Is this "new" design considered superior to the old?
2) should I just go ahead and pony up for 3 more pistons so I have a matching set? (these babies aren't cheap!)
3) Does it matter which direction I orientate the piston in the cylinder, since there doesn't seem to be a locating arrow on top?
4) Does it matter which way I install the rods on the crank (i.e., with reference to the bearing locating slots in both rod halves?
Any help would be appreciated.
Phil Auldridge Austin, Texas - USA
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53 SQ 4 MK II, '72 Norton Commando, '78 BMW R100/7, '79 Honda CBX, 2014 Indian Chief Vintage