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.
Sent from my SM-A520F using Tapatalk
Crank shaft bearing beds wear?
-
- Posts: 291
- Joined: Sun Sep 16, 2012 7:10 am
- Location: gold coast Australia
Crank shaft bearing beds wear?
Last edited by graham heise on Thu Jun 14, 2018 7:09 am, edited 1 time in total.
yamaha fanatic.
-
- Posts: 291
- Joined: Sun Sep 16, 2012 7:10 am
- Location: gold coast Australia
Re: Crank shaft bearing beds wear?
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.
yamaha fanatic.
Re: Crank shaft bearing beds wear?
Graham, you could always bolt the cases together and have them measured for tolerance. That would give you a better idea.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
-
- Posts: 291
- Joined: Sun Sep 16, 2012 7:10 am
- Location: gold coast Australia
Re: Crank shaft bearing beds wear?
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.
yamaha fanatic.
Re: Crank shaft bearing beds wear?
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?
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
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
Re: Crank shaft bearing beds wear?
Lockite bearing Lock.. Works!.. period .
-
- Posts: 291
- Joined: Sun Sep 16, 2012 7:10 am
- Location: gold coast Australia