Crank shaft bearing beds wear?

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graham heise
Posts: 238
Joined: Sun Sep 16, 2012 7:10 am
Location: gold coast Australia

Crank shaft bearing beds wear?

#1 Post by graham heise » Wed Jun 13, 2018 2:45 pm

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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Last edited by graham heise on Thu Jun 14, 2018 7:09 am, edited 1 time in total.
yamaha fanatic.

graham heise
Posts: 238
Joined: Sun Sep 16, 2012 7:10 am
Location: gold coast Australia

Re: Crank shaft bearing beds wear?

#2 Post by graham heise » Thu Jun 14, 2018 6:46 am

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.
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hondaror
Posts: 2831
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Crank shaft bearing beds wear?

#3 Post by hondaror » Sun Jun 17, 2018 4:26 am

Graham, you could always bolt the cases together and have them measured for tolerance. That would give you a better idea.
Rory

graham heise
Posts: 238
Joined: Sun Sep 16, 2012 7:10 am
Location: gold coast Australia

Re: Crank shaft bearing beds wear?

#4 Post by graham heise » Sun Jun 17, 2018 7:17 am

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.
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hondaror
Posts: 2831
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Crank shaft bearing beds wear?

#5 Post by hondaror » Mon Jun 18, 2018 3:57 am

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?
Rory

Bare
Posts: 1133
Joined: Sun Jan 29, 2006 2:18 am
Location: vancouver

Re: Crank shaft bearing beds wear?

#6 Post by Bare » Thu Jul 19, 2018 11:42 pm

Lockite bearing Lock.. Works!.. period .

graham heise
Posts: 238
Joined: Sun Sep 16, 2012 7:10 am
Location: gold coast Australia

Re: Crank shaft bearing beds wear?

#7 Post by graham heise » Fri Jul 20, 2018 4:47 am

loctite bearing lock. i use it.
yamaha fanatic.

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