I have a JX75 with a broken connecting rod. The piston, rings and cylinder look great. The upper bearing surface on the lid of the engine and the top of the crankshaft that passes through the lid/ bearing are both scored. I am asking for input as to how smooth both surfaces need to be…and how you would attempt to remove/smooth out the scoring. The journal on the crank for the connecting rod does not look bad at all. All of the damage is at the flywheel end of the crank just below the top seal. I assume from a lack of lubrication. This engine has an oil pump and oil is supposed to be pumped up to the top bearing. I did not take a photo of the damage to the crankshaft or the bearing surface in the lid…hopefully the description is enough.
Any and all comments and guidance is welcome
yes it is at least 30 years old. The piston and rings as well as the cast iron cylinder sleeve look great. I have not pulled the crankshaft completely out of the engine so I have not seen the lower bearing surfaces on the crankshaft or the sump/bucket look. Also I haven’t been able to completely inspect the condition of the crankshaft journal for the connecting rod…but what I have seen doesn’t look bad. I do not see any galled metal from the old rod on the journal. If there is… some muratic acid and very fine sandpaper should clean it up.
What I am asking for is anyone’s experiences with dressing both the crank and the bearing surface in the top lid for scoring. How to best dress/resurface and remove or reduce the scoring.
I know that the top lid is NLA and the bearing is not separately replaceable, so if there is no way to recondition the bearing surfaces on that lid the engine will have to be scrapped.
