I bought an old 124 that is rough and would not run.when I got it running the clutch and release brg.were noisy.I fixed this problem and now engine sounded like a loose rod.when I changed the oil it looked like tar.I pulled the engine down and to my supprise the crank and rod were slick and in specs. the piston looks good but I cain`t measure the bore. the crank brgs.feel good .every thing is std.I made a small adj. on exhaust valve.valve guides are not loose. end play on crank shaft is on low spec.are these engines normally noisy? any ideas appreciated mesmith.