Topic: wear of crankshaft bearings CB 750 K2

[olasek18_18@o2.pl]

Hello,
 I have a question, is it normal wear of crankshaft bearings ?
 I took apart the engine and plan to measure everything, I have no experience with this yet.

Regards

[bryanj]

Thats dirty oil, shells dont look too bad but those pin markings are bad, unusual for it to be that way round

[Tracksnblades1]

Thats dirty oil, shells dont look too bad but those pin markings are bad, unusual for it to be that way round

+1 ..👍

And looks like the oil had drawn moisture (water). These old air cooled Hondas used to get their oil changed every 1000 miles back in the SD/SE oil rating days.

[olasek18_18@o2.pl]

Thats dirty oil, shells dont look too bad but those pin markings are bad, unusual for it to be that way round

where is pin markings? What You mean?

[bryanj]

The visible grooving on the crankshaft itself

[Ujeni]

A common problem from the CB750 engines I have rebuilt. Time to polish the crank journals and replace the crank bearings. Safe bet your connecting rod shell bearings will need replacing as well. Use green plastigauge to make sure you have the right shell bearings for both.

[Rosinante]

Agreed.  And all the "while you are in there" stuff that makes sense.  Like measuring.  I have rebuilt only one significant engine, and I failed to measure the big ends of the rods.  That engine is doing fine, but I always wondered whether those big ends are actually still round.  The crank main and rod bearing journals were beautiful, as new, but......