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TOPIC: Re:Main Bearing inserts.
#1027540
BikerRon (User)
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Re:Main Bearing inserts. 4 Days, 17 Hours ago  
If all thatís needed is scheduled oil changes, I know Iíll never have to get to that point.
 
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#1027543
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Re:Main Bearing inserts. 4 Days, 16 Hours ago  
BikerRon wrote:
If all thatís needed is scheduled oil changes, I know Iíll never have to get to that point.



 
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#1027546
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Re:Main Bearing inserts. 4 Days, 12 Hours ago  
Thanks to all who answered.
No, the crank does NOT ride on the crankcase housing. There ARE inserts. They just tell you that they're non replaceable. I'm old school too. You might have to spec out your own, but i have no doubt you could find something that would work. Even if it meant having the main journals on the crank ground down a little to match whatever you could find for bearings. where there's a will, there's a way.
The bearings are NOT installed and then line bored. from a manufacturing standpoint, this would make no sense at all. The housing has to be line bored. why in the world would you make the inserts so sloppy that they needed to be line bored also after installation. Not to mention; the babbit surface of modern bearings is typically less than .001". No room for line boring there. Bearings haven't been line bored after installation since Ford flathead V8s.

No, this (I suspect, and am seeking confirmation on), is just a giant line of bull$@!t. True; at the moment i have no need to replace any main bearings. i'm just seeking correct information. If someone could come up with a plausible reason why they CAN'T be replaced, i'd love to learn about that. I'm not claiming to be (and do not wish to be perceived as) a know-it-all, but I've been building my own M/C and automotive engines for 40+ years. I was previously employed by an engine parts warehouse, serving machine shops all over the northeast. One of my main responsibilities was to identify parts for obsolete machinery that would serve as suitable replacement parts, with or without some minor (or sometimes major) modification. (did you know Corvair pistons will work in a flathead Harley?) I'm just saying . . . I need to know why these bearing "can't" be replaced. I seriously doubt it. Yamaha may have made no accommodations to replace them. I'd like to know why. Nothing magical going on inside these engines that is obvious to me. I'm always open to enlightenment, however. So anyway, what I'm actually hoping for is for a legit Yamaha tech to give me the story that Yamaha has come up with on this, and can tell me the story without making me laugh.

And just to address the obvious error; there are no roller or ball bearings used with this crankshaft. Someone must be looking at their Harley manual.

Anyway, thanks again. Hoping to hear more.
also, . . . . it breaks my heart that this site is shutting down. I hope someone with the needed resources sees fit to rescue it. There are other Roadstar sites out there, but not like this one.

Ride safe,
Pete
 
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#1027547
davej (User)
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Re:Main Bearing inserts. 4 Days, 11 Hours ago  
Peter Blair wrote:
Thanks to all who answered.
No, the crank does NOT ride on the crankcase housing. There ARE inserts. They just tell you that they're non replaceable. I'm old school too. You might have to spec out your own, but i have no doubt you could find something that would work. Even if it meant having the main journals on the crank ground down a little to match whatever you could find for bearings. where there's a will, there's a way.
The bearings are NOT installed and then line bored. from a manufacturing standpoint, this would make no sense at all. The housing has to be line bored. why in the world would you make the inserts so sloppy that they needed to be line bored also after installation. Not to mention; the babbit surface of modern bearings is typically less than .001". No room for line boring there. Bearings haven't been line bored after installation since Ford flathead V8s.

No, this (I suspect, and am seeking confirmation on), is just a giant line of bull$@!t. True; at the moment i have no need to replace any main bearings. i'm just seeking correct information. If someone could come up with a plausible reason why they CAN'T be replaced, i'd love to learn about that. I'm not claiming to be (and do not wish to be perceived as) a know-it-all, but I've been building my own M/C and automotive engines for 40+ years. I was previously employed by an engine parts warehouse, serving machine shops all over the northeast. One of my main responsibilities was to identify parts for obsolete machinery that would serve as suitable replacement parts, with or without some minor (or sometimes major) modification. (did you know Corvair pistons will work in a flathead Harley?) I'm just saying . . . I need to know why these bearing "can't" be replaced. I seriously doubt it. Yamaha may have made no accommodations to replace them. I'd like to know why. Nothing magical going on inside these engines that is obvious to me. I'm always open to enlightenment, however. So anyway, what I'm actually hoping for is for a legit Yamaha tech to give me the story that Yamaha has come up with on this, and can tell me the story without making me laugh.

And just to address the obvious error; there are no roller or ball bearings used with this crankshaft. Someone must be looking at their Harley manual.

Anyway, thanks again. Hoping to hear more.
also, . . . . it breaks my heart that this site is shutting down. I hope someone with the needed resources sees fit to rescue it. There are other Roadstar sites out there, but not like this one.

Ride safe,
Pete


Plain and simple Yamaha says they are non replaceable because they don't sell them and they had no intention on them being replaced. The reason the dealer gave you is a line of BS I agree. You are also correct about where there is a will there is a way but at what cost??? You may be able to bring in the cases to a machinist or Crankshaft shop to see what they could do for you but IMO that would be a waste of time and money. You can get a replacement engine for less than it would cost to devise a way to replace something that rarely needs replaced. In my 9 years of owning a Roadstar I have only heard of 1 motor going bad to the point of being scrap. I also know quite a few members that have well over 100K and some 200K without an issue and refreshment of the motor is not yet needed.
I'm not quite sure what magical answer you are looking from here at the RSC, maybe a call to Yamaha tech support would be a better avenue for you. BTW I have also been a Master certified mechanic in Auto and heavy duty truck ( I didn't see that in your short list of qualifications)along with being a Journeyman Equipment Repair Specialist and retired after working as a mechanic for over 35 years and have a bit of experience in rebuilding engines of all sorts so I take a little offense to your tone with the members here that have thrown around a couple thoughts trying to help you. With none of us being Yamaha engineers we obviously can't give a absolute answer all we can do is to throw out thoughts for questions like the one you have. As far as looking for a legit Yamaha tech as you call it, you have already talked to one that gave you the lining up the hole answer.
 
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Last Edit: 2018/01/14 12:02 By davej.
 
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#1027552
BikerRon (User)
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Re:Main Bearing inserts. 4 Days, 9 Hours ago  
No, the crank does NOT ride on the crankcase housing. There ARE inserts.

And just to address the obvious error; there are no roller or ball bearings used with this crankshaft. Someone must be looking at their Harley manual.


How many times you going to shove that in my face?

Yea, I revised my observation about them being ball bearing in a later post. No harm, no foul.

Looking at .pdf files on an iPhone can be taxing, at times.
 
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Last Edit: 2018/01/14 08:59 By BikerRon.
 



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#1027556
Father_Pobasturd (User)
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Re:Main Bearing inserts. 4 Days, 5 Hours ago  
It's all good guys, brothers fight all the time. This is more like the spirit of the old RSC...I welcome it.

I have seen this discussion on here before, and I came away with more questions than answers. Why would a manufacturer build an engine with plain bearing main bearing inserts, and not offer the plain bearings as replacement parts? It's entirely possible those plain bearings are used in a different motor where they are replaceable. To figure that out would take a lot of research. Let me pose this question..do the Road Star plain bearings have a part number? If so they could possibly be cross referenced to another Yamaha P#. If they don't. they would have to be removed from the cases, measured, and searched for by their size (a real pita).

With the bikes discontinued, this issue will come more to the forefront as time goes on. More bikes going over 200K, oil pump failures, abuse, any number of reasons will conspire to make this a more prominent issue than it is now. Perhaps finding a solution sooner than later may be a good idea.




 
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#1027566
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Re:Main Bearing inserts. 3 Days, 23 Hours ago  
Again there are enough replacement engines available along with the miles these engine live and the low value of these bikes main bearing replacement should never be an issue. This is also not an issue that needs any attention and if the OP wants to know how and why, maybe he can be the pioneer and give us the answer. Hell like he said anything is possible. Hell anything IS possible, machine the case and crank then find a ball bearing that will spec and fit. It just take time and money. If someone wants to spend time and money on what at the time and mileage that a main bearing will be needed on what will be $1000 bike if it was in running condition. I hope they have fun. At that time the bike will barely be worth buying and installing a replacement engine. You would be ahead of the game parting the bike out from what is left.
 
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#1027573
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Re:Main Bearing inserts. 3 Days, 19 Hours ago  
I was just thinking down the line, say, maybe 10 years, there may not be so many spare engines / cheap bikes like there are now. It could come to a point where it's a viable option to replace those plain bearings. Not on a level that would create a market for them.
 
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#1027575
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Re:Main Bearing inserts. 3 Days, 18 Hours ago  
Father_Pobasturd wrote:
I was just thinking down the line, say, maybe 10 years, there may not be so many spare engines / cheap bikes like there are now. It could come to a point where it's a viable option to replace those plain bearings. Not on a level that would create a market for them.


The bikes have little value now and in 10 years the older ones won't be worth fixing if all of the sudden they mysteriously start having main bearing problems that they don't have now. After a few 100K miles it may just be time to move on. Kinda like who is looking for a motor or fix for a 1989 goldwing? The answer is probably no one.

Trying to find a fix for something that isn't and hasn't been a broke or problem part is silly. But if someone wants to devise a repair without really doing the repair, (we will call it a virtual repair) they are welcome to report back their findings.
 
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Last Edit: 2018/01/14 10:58 By davej.
 
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#1027578
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Re:Main Bearing inserts. 3 Days, 14 Hours ago  
Virtually, of course.

As much as it pains me to say, the affordability of the Roadie goes right out the window, when the repair is about 2 or 3 times the price of the bike. People will still be finding these with minimal miles in their dad's garage, long after I'm taking a dirt nap. I don't think they'll ever have the longevity of interest shown to some things that go varoom. Then again, I can't figure out what button you'd hope you were pushing when you accidentally pushed the wrong one and sent millions of people into a panic. That's just me. I lack imagination.
 
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