Hey gents, I'm putting my '70 A65L back together after having some machine shop work completed by Bill Coleman in Baltimore after numerous recommendations to use him. I had about 2500 miles on the bike since my last rebuild, but wanted to take care of some nagging problems. 2500 miles ago, I had the journals ground to .010 under and the bike ran fine after that. I just put the connecting rods back on with new bearings, but they feel a little bit tight. We're not talking outright binding, but I have to give the connecting rod a little nudge for it to fall on its own. I also tried using the old bearings, but had the same issue. No new work was done on the crankshaft.
Mr. Coleman checked the crankshaft journal tolerances and said they were good. I checked the tolerances between the connecting rod big ends with bearings and the journals. My calipers said .0015" tolerance. I also use plastigauge which indicated it was between .001" and .0015" tolerance, but more toward the .001" side. The manual says .001"-.0025" bearing diametrical clearance, so I assume I'm within the tolerances? As it ran fine before, should I not worry about it and reassemble, or is this an issue?
This may sound like a daft solution but try bring the lump ( crank, rods) into the warmth of the house.
On my current build, the rods showed zero play on the rods, however when I put the micrometer ( calibrated) on the journals they both read .005" under spec. As it was about 1°c when I measured the journals I decided to bring the crank and the micrometer into the house for a couple of days. After the first day the journals still felt very cold, after the second the whole crank felt warmer so I measured again ( about 16°c) the journal size had grown upto the specs written in the book.
Don't forget to use assembly lube on the shells when installing.
Yeah, crankshaft and con rods are inside...have been for almost a week since it's too cold to work outside. I might try heating up the rods to see how easily they fall. Either way, it looks like I'm going to keep them as-is.