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PostPosted: Mon May 05, 2014 5:30 pm 
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Clutch Springs
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That is just... weird. The Haynes manual doesn't state (at least not in the engine over0haul section) anything about the bearing size/type. Only about removal and installation procedures and the REQUIREMENT to replace the bearings any time the case is split and/or signs of bearing wear/failure.

Other then that, there is no mention of a different bearing for the case or the crankshaft...


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PostPosted: Mon May 05, 2014 6:26 pm 
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I've found aftermarket manuals are not usually up to snuff in comparison to the OEM service manual but, often they do contain additional information that the OEM manuals don't. In particular, I noticed that the OEM Honda Service Manual does not explain how anything works but they do an excellent job of detailing everything else. Assembly, disassembly, testing - it's all there. In fact, I'd have to say it's close to one of the best service manual's I've seen other then that one glaring defect....

General Motors makes some great ones. Typically, each section contains a complete description of the operation of the components. In the case of electrical systems they explain the entire circuit function. If you were in the transmission section they would explain how it works as well as how to service it - something that can be really handy (such as in the case of the transmission in my bike and the 5 => 4 intermittent down-shift issue.

With respect to the bearings and the crankshaft, they are unique to Honda and specially made by NTN for Honda. Even though they are a 6207 series bearing they are fully 2mm thinner then a 6207 which makes them... a Frankenstein.

And of course, that means dealer only item. The issue gets compounded though when the dealer reports the bearing on the crank is no longer available. That specific bearing fits every CBR125 from 2004 through to 2013 and, in all likelihood, the 2014 as well. I believe it also fits every CBR150 made. So there's an issue there and it seems to be on Honda's side....and I'm caught in the middle of it.

A careful search on the Internet shows only ONE other person in the world to run into this issue and that's a fellow in Japan doing up a nice racing CBR150. He took a picture of the bearing and wrote a caption underneath it. When translated it came out to 'the evil bearing from hell' or words to that effect. He too found out the same thing. Mind you, being that he's in Japan, he could always vent his frustration by tossing the bearing through Honda's window. That would be one way to order parts :laugh:

I've got my parts people looking into it. They're going to call Honda and try and find out why you can only buy the case-side crank bearing. But, as I was saying earlier, it would be nice if they did a description of the operation. If they did, perhaps they would mention WHY they specify that the crank bearing (the one you cannot buy) MUST be replaced every time you split the case. Other then the obvious (you might as well) it would also be nice to know exactly how that crank bearing is different from the case-side bearing when they are dimensionally identical. Tighter clearances, looser clearances, tougher balls (?) , different steel, different heat-treating, higher loads on that side (and the reasons why) would all be very nice to know.

But so far, the bottom line is they are a dealer only item. You cannot go into the aftermarket for them as you can with almost every other bearing in the world.

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PostPosted: Tue May 06, 2014 7:49 am 
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The usual cause of a part needing to be replaced whenever it or its environment are disturbed is that they are expected to distort or be damaged during dismantling: witness the pretty standard requirement of replacing big-end bolts - having been torqued up to their operating tension and then released, the bolts cannot safely be used in the same context again, as they stretch during the initial torquing.
Thus I'd venture that the skinnier bearing is under-strength by dint of it's narrower races and is likely to be distorted - however slightly - by disturbing or removing it.
Why did Honda specify this "thinner" bearing? I'd take a punt on the designers being required to use existing crankcases and/or crankshaft common to other models, but needing something else (crank counter-balance weights, perhaps?) to be larger/heavier/sturdier and therefore take up more space.
Having the 'special' bearing to be no longer available is rather poor on Honda's part: the logical extrapolation is that once a CBR125/150 engine needs to be opened up, it's effectively scrap.

Tell me it isn't so!!!!


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PostPosted: Tue May 06, 2014 1:13 pm 
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Precis wrote:
The usual cause of a part needing to be replaced whenever it or its environment are disturbed is that they are expected to distort or be damaged during dismantling: witness the pretty standard requirement of replacing big-end bolts - having been torqued up to their operating tension and then released, the bolts cannot safely be used in the same context again, as they stretch during the initial torquing.

Thus I'd venture that the skinnier bearing is under-strength by dint of it's narrower races and is likely to be distorted - however slightly - by disturbing or removing it.


Good point. That could be it, or, at least, a part of it :top:

Precis wrote:
Why did Honda specify this "thinner" bearing? I'd take a punt on the designers being required to use existing crankcases and/or crankshaft common to other models, but needing something else (crank counter-balance weights, perhaps?) to be larger/heavier/sturdier and therefore take up more space.


That would make sense. Also, the width of the bike might play a role in it. The bike would be 4mm wider with the stock series of bearing. It could be anything along those lines but I suspect you're on the right track.

Precis wrote:
Having the 'special' bearing to be no longer available is rather poor on Honda's part: the logical extrapolation is that once a CBR125/150 engine needs to be opened up, it's effectively scrap.

Tell me it isn't so!!!!


Well, here's the thing, the bearing we apparently can't get is the one pressed onto the crank. But we can get a new crank.... I'll leave that to your imagination :laugh: My guess is that a new crank probably comes with the bearing pressed onto it...

I measured both the bearing we can get (the crank bearing that's pressed into one case half) and the bearing we can't get (which is pressed onto the crank). Both are dimensionally identical. Both have the same number of balls. Both are made by the same company and 75% of the part number from the bearing company is the same.

So, there is a difference between them, but no-one knows what it is. In my case (pardon the pun) I ordered up two of the case-side bearings from Honda. They are, after all, dimensionally identical. So I currently plan on pressing one onto the crank and one into the case. Problem solved.

But here's the thing, what is the difference between them? Same dimensions, same number of balls. Could it be that the balls are larger/smaller? I do know that bearing companies have 'loose fit' variants and 'tight fit' variants depending on the design requirements.

My guess is that to properly deduce the reasoning we would need to understand the forces on the crank and what would make Honda differentiate between left and right or view them as requiring two different bearings. One special, and one not. Even though, they actually both are.

Here's another thing...people in AUS do list the bearing on their sites along with a price (about $90 AUD!!!!!!!) :sad: :ohmy: :blink: :rolleyes:

If they actually have stock on it, methinks they might be gouging on the basis that it's an oddball bearing (pardon another awesome pun!)

I do have my parts guy looking into it though. So he will call Honda and we will get an answer. This bearing is used on every CBR125 made as well as the CBR150 so this may just be, for all I know, a mess-up by Honda. Perhaps they actually have 10,000 of the damn things in stock and they are not selling them because their parts department screwed up on the parts listings....

Rest assured, at some point we'll get our bearings on this issue (oh man, that's just too good to pass up) :laugh: In the meantime, I'm having a ball....

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PostPosted: Tue May 06, 2014 1:33 pm 
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Quote:
Rest assured, at some point we'll get our bearings on this issue (oh man, that's just too good to pass up) :laugh: In the meantime, I'm having a ball....


Oh Marvin... PLEASE don't give up your day job!! :laugh:


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PostPosted: Tue May 06, 2014 1:36 pm 
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grenadiers wrote:
Quote:
Rest assured, at some point we'll get our bearings on this issue (oh man, that's just too good to pass up) :laugh: In the meantime, I'm having a ball....


Oh Marvin... PLEASE don't give up your day job!! :laugh:


Actually, I've been thinking of re-joining the rat race :ohmy: :laugh:

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PostPosted: Tue May 06, 2014 3:25 pm 
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Puny puns aside, I expect that any material differences in the apparently-identical bearings will be down to one being, effectively, a DRIVE bearing and the other a DRIVEN bearing. Dimensions may be identical, but I'd guess they differ in material - which might also have something to do with oil supply.


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PostPosted: Tue May 06, 2014 6:48 pm 
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Precis wrote:
Puny puns aside.....


Uh huh - let's see what you got.... :biggrin:

Precis wrote:
I expect that any material differences in the apparently-identical bearings will be down to one being, effectively, a DRIVE bearing and the other a DRIVEN bearing. Dimensions may be identical, but I'd guess they differ in material - which might also have something to do with oil supply.


could be...I just heard back from out parts people and they have a call into Honda and the issue is now moving up the chain. I was told we can expect a call from someone knowledgeable in a few days. My guess though is that they won't be knowledgeable about the genetic makeup of the bearing - probably more in line with whether it really is available or what the official scoop is on getting them.

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PostPosted: Wed May 07, 2014 4:02 pm 
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OK, here's the official scoop from Honda on the crankshaft bearing (part # 91002-KPP-901)

This bearing is not available to Canada. If you want to buy this bearing in Canada you can buy a new crankshaft, which comes with the bearing :rolleyes: That's one way to replace a bearing :laugh: Another would be to buy a new bike. That would also replace the bearing :laugh:

However, Honda does sell that bearing through US dealers so you can buy the bearing from them and have them send it up to Canada (assuming you find a dealer willing to do so).

Of course, this decision makes perfect sense given that the CBR125r is not sold in the USA. So, of course, that's why you would chose to sell the bearing to them and not to the country where the bikes are actually sold. :rolleyes: :blink: :unsure: :wacko:

So you have to go to a country that doesn't sell the CBR125, buy the CBR125r bearing from them, and then import that bearing into the country that does sell the CBR125r.

What I'm going to do is just use two of the case side crank bearings as they are dimensionally identical and Honda Canada can get them. If anyone else is doing this job I'd recommend just buying that crankshaft side bearing ahead of time from the US and then buying the other locally and sourcing the others from the aftermarket.

This way you'll have all your bearings in a row before you do the job :top:

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PostPosted: Thu May 08, 2014 2:49 am 
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What is the US price from Honda dealer. I am heading south during the summer and could have a few sent to my buds house to pick up. Looks like early to mid July.
A search only turns up overseas suppliers though.

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