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I bought a crank on ebay. It was from an engine that had never been bored. I checked run-out, rod side-to-side play, no up and down play. I replaced outside bearings for good measure, got new seals and assembeld crank cases. After mounting in bike frame, I happened to notice that one side of one rod was pink at the bottom end. Is this bad?  I took pics of both rods. see images

I do not know how to start a new topic.  So, I also bought a RD400C crank on ebay. It came from a low-use engine. I checked the rod bearing play side-to-side. There is no up and down play and checked crank shraightness, replaced the outside bearings and got new seals. After putting engine in the frame, I then noticed that one rod has a pink area on one side at the crank bearing.
Is this bad? I took pics of the other side and other rod. see pics

My crank is removed from the engine. I need to tighten the primary gear nut. The service manual sequence to tighten the nut is to place someting soft between the clutch gear and the crank gear and tighten.  I worry about causing damage to the bearings, shafts, gears or cases. Since I have the crank out of the engine, shouldn't I use a clutch holding tool and torque wrench to tighten the primary gear nut, insert the crank and then assemble the engine cases? A different service manual suggests putting the bike in gear and torqueing the nut!

I saw no place to start a new topic. So.... My RD400C service manual instructs me to bolt together the cases and then tighten the crank gear nut with something soft between clutch and crank gears. To me, I worry about doing damage to the gears, bearings, cases or the shafts. Why not tighten the crank nut while holding the crank with a clutch holding tool before putting the cases together?

If it helps, I sent a RD400 crank for an estimate. Labor is $375 to rebuild, but the estimate is much less. To rebuild with 4 new roller bearings, both rod bearings, rod thrust washers and both solid pins, it is $651. Crank Works is busy and wait time might be long.