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Crank shaft bearing beds wear?

Posted: Wed Jun 13, 2018 2:45 pm
by graham heise
I have been cleaning up my 4l0 engine parts ready for re assemble. I noticed a small lip on the bottom case half where the left side inner crank crank bearing sits. (Adjacent to labyrinth seal). There is also a small lip to the outside of the outside crank bearing. I have checked over some other cases i have and none have this lip (indent). The top half of the case is good. This engine was running a few weeks ago and there was no binding on the crank and the crank has been checked and is still true. looking at the cases it shows evidence of the other inside (right) crank bearing maybe being slightly loose, causing some chattering? Any tboughts on this gents?
I now have a spare set of good cases, all be it wrong engine number. Should i be looking at using these cases instead. ImageImage

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Re: Crank shaft bearing beds wear?

Posted: Thu Jun 14, 2018 6:46 am
by graham heise
Had my lc crank trued today. show'd the crank cases to the guy. He said he's seen to many cases like it, could pull the crank out of true. Recommended i use the spare cases.

Re: Crank shaft bearing beds wear?

Posted: Sun Jun 17, 2018 4:26 am
by hondaror
Graham, you could always bolt the cases together and have them measured for tolerance. That would give you a better idea.

Re: Crank shaft bearing beds wear?

Posted: Sun Jun 17, 2018 7:17 am
by graham heise
what we be the tolerance? Maybe i could have used them but i decided to go with the spare cases. i completed the rebuild today, been through 5 heat cycles and all seems well.

Re: Crank shaft bearing beds wear?

Posted: Mon Jun 18, 2018 3:57 am
by hondaror
Good work.

As for clearances, I'm not sure what the specs are. The machinist in me says 0.0005", is the standard bearing fit. Yamaha should have a spec somewhere. Anyone?

Re: Crank shaft bearing beds wear?

Posted: Thu Jul 19, 2018 11:42 pm
by Bare
Lockite bearing Lock.. Works!.. period .

Re: Crank shaft bearing beds wear?

Posted: Fri Jul 20, 2018 4:47 am
by graham heise
loctite bearing lock. i use it.