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TOPIC: Re:Main Bearing inserts.
#1027501
Peter Blair (User)
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Main Bearing inserts. 5 Days, 11 Hours ago  
Ok, so i'm not doing an engine job on my Roadstar at the moment, but i couldn't help but notice;
In the service manual, they say that you cannot replace the insert type main bearings. They say the crankcase should be replaced. I thought that maybe some new technology has been applied during factory assembly, preventing the successful removal and replacement of said bearing. I called a local dealer and spoke to the service department. They told me it was because replacing the bearing would require accurate alignment of the oil hole in the bearing, to the oil galley hole feeding the bearing housing in the case. I said "thanks for the information". So . . . do they think that someone who could strip an engine down to this point might not posses the skill to line up two holes upon assembly? This just doesn't seem right to me. Is there someone out there who could verify this, or give me the strait dope, whatever the case may be? Preferably from a legit Yamaha tech (my preference, but I'd be happy to hear from any/ all that have information on this).
Thanks in advance for the help.
Pete (waiting out the winter)
 
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#1027502
Salem (User)
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Re:Main Bearing inserts. 5 Days, 11 Hours ago  
Lining up holes isn't a big deal. It's done all the time with automotive cam bearings.
 
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#1027503
BikerRon (User)
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Re:Main Bearing inserts. 5 Days, 10 Hours ago  
We talking main bearings on each end of the crank?

Those are ball bearings used for mains. I saw nothing about replacing the cases in my manual.

Just gives the tolerances of the crank that fits in the inner races of those two bearings and replacing the crankshaft if out of specs.
 
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#1027513
davej (User)
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Re:Main Bearing inserts. 5 Days, 9 Hours ago  
BikerRon wrote:
We talking main bearings on each end of the crank?

Those are ball bearings used for mains. I saw nothing about replacing the cases in my manual.

Just gives the tolerances of the crank that fits in the inner races of those two bearings and replacing the crankshaft if out of specs.


Where did you find Ball bearing mains in the parts fiche? The fiche don't show any replaceable bearing.
 
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Last Edit: 2018/01/12 19:20 By davej.
 
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#1027524
BikerRon (User)
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Re:Main Bearing inserts. 5 Days, 9 Hours ago  
Never saw them in the parts fische, either. But, in the service manual it describes the journal’s specs.

Just never saw anything about replacing the cases if you pull the crank. Guess they figure those are ‘forever’ main bearings and never need replacing.

https://imgur.com/gallery/3ZHoK
 
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Last Edit: 2018/01/12 20:03 By BikerRon.
 



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#1027535
davej (User)
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Re:Main Bearing inserts. 4 Days, 23 Hours ago  
I'm not 100% sure because I never had one apart to that point but I'm almost sure the case surface is the bearing just like on some of the smaller air cooled engines. JMO but if I was gonna freshen up a motor I wouldn't worry about it unless there was a specific issue in that area or unless the motor was run out of oil or lost a oil pressure for some reason. Again IMO a valve grind,oil pump,set of rings and rod bearings to freshen a motor that has a couple hundred thousand miles on it would be all that is needed.
 
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#1027536
BikerRon (User)
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Re:Main Bearing inserts. 4 Days, 21 Hours ago  
....but I'm almost sure the case surface is the bearing just like on some of the smaller air cooled engines.


I stand corrected, Dave. I believe you’re right about the crank spinning in the case’s own material for bearings and I’m blown away. Briggs and Stratton comes to mind. After looking through dozens of pictures on the web of XV 1600 and 1700 engine cases I never saw a plain bearing insert in any of them.

Further research in the service manual did show the specs for the case ID limits for wear and said the cases would have to be replaced, if exceeded. What in the world? No inserts?

So, what was that service guy feeding him about lining up the galley holes?

What amazes me is all the threads in RSC about people losing oil pressure due to pump gear failure and riding for miles until the lifters collapsed and brought it to their attention with all the racket that something was up.

I just don’t see how the crank bearing material (aluminum) survived an episode of that magnitude after they replaced the pump gear and kept going.

Edit.

Tho this is a 1600 case, now, I see bearing inserts. Can even see the notches for proper alignment and to keep them from spinning. But, they’re non replaceable?

https://m.ebay.com/itm/2001-Yamaha-Road-Star-Xv1600a-Left-Engine-Motor-Crankcase-Crank-Case-Block-XV-01/252823860156?hash=item3add79f3bc:g:wdQAAOSwax5Y0WsN
 
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Last Edit: 2018/01/13 07:56 By BikerRon.
 



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#1027537
davej (User)
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Re:Main Bearing inserts. 4 Days, 19 Hours ago  
Good pic!!! That explains alot
 
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#1027538
jinxpress (User)
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Re:Main Bearing inserts. 4 Days, 17 Hours ago  
Wow ! I hope I never need to get to this point

Quote "Can even see the notches for proper alignment and to keep them from spinning. But, they’re non replaceable? " Unquote

They are inserts, someone put them in there. I'm old school when it comes to taking something apart. My thought is (hey, someone put it together, so it otta come apart).

Could it be that the inserts are installed in cases, assembled, line bored, then taken apart. This would mean that the cases are a MATCHED set.

I'm confused
 
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#1027539
davej (User)
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Re:Main Bearing inserts. 4 Days, 17 Hours ago  
good chance of that Tom. I'm going back to what I said earlier about not worrying about it unless it is trashed and then if it is a replacement engine would be cheaper than trying to figure out how to repair. I would sure hate to buy a case 1/2 just to find out that things didn't fit proper.
 
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