Need help with piston bearing

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eisle89

New Member
Jun 16, 2008
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El Paso, Texas
Is there a higher quality roller bearing to fit what I think is the 12mm wristpin. I needed to
replace a piston and head because they were running into each other ( about an 1/8") around
the outside edge. The piston I got from DAX has too big of a wristpin. so now I guess I have
to find the bigger wrist pin AND a a roller bearing with the same ID assuming that the OD
is the same to all the cranks. Does anyone have a bearing chart for the different fits ?? TIA
 
Bikeguy Joe

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
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I would have returned the engine before I took it apart if the piston was hitting.

Was your old wrist pin using a bearing or a bushing?
 
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eisle89

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Jun 16, 2008
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El Paso, Texas
Well, my big theory is that after awhile the crank might have stretched a little and
the upper crank arm was sliding side to side on the roller bearing itself.
The engine is an old powerking 80 and I'm trying to figure out how I can use the 12mm
pistons from DAX and just replace the 10mm wrist pin and bearing. I did a search and read
through a bunch of posts where other people had the same trouble and replaced the bearing
and added shims.
I guess I'll try that ... or give up and buy another engine, but no one has just the engine
in stock right now. Thanks
 
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ivan H

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Oct 8, 2011
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Ok, I know this is a very old thread, & I have never heard of a piston hitting the head before unless the small end bearing has colapsed, which they sometimes do, they're low quality. You should normally have about 0.8mm deck height. The problem is they use a 13mm wide bearing & the bosses on the piston are almost 16mm between. Replace the bearing with a quality 10x14x15 bearing. Eliminates bearing float & support the piston properly
 
Toadmund

Toadmund

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Jan 19, 2012
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Any good make cheaper bearings?
My budget is tight and in another thread someone put up a link for some nice IKO bearings, only under $7.00.

Catch was, the (international) shipping charges to Canada is $24.00.

I don't like paying more postage than the item is worth.

It's one bearing for crying out loud, why do I have to pay for a one size fits all postage rate?

I can't seem to find a good cheap wrist pin bearing with a decent postage rate.

So, if anyone knows their bearings, help let me find mine.
I am sure their are lots of moped, scooters, pocket bikes, and small motorbikes that use a 10x14x15, but most websites do not list the size, just the make of bike it is used on, also the sizes, some of them are close, but just a touch off, like maybe .2mm and such.

Thanks.
 
Toadmund

Toadmund

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Jan 19, 2012
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Saint John, New Brunswick, Canada
It's bearings direct I am complaining about.

(I learned this on another forum I don't know if I can mention it) I am considering
just getting the regular size bearing and putting nylon compression fittings used on plastic plumbing pipes as spacers between the needle bearing, they are very light and apparently can withstand the heat under the piston.

So, I seemed to have forgot what the regular size of bearing searching in vain for IKO 10x14x15.

This is it right?
I am sure it is, but I want to be 100% sure:
http://www.vxb.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=bearings&Product_Code=kit945&Category_Code=NEEDEL_ROLLER

I don't need this bearing now, but I want it when I tear down my upper, I will replace that, add the nylon spacers, but before that I will trim the piston skirt on the intake.

The shipping to Canada is 10 dollars (for 2, probably same for 1), still steep, but I can live with that.
 
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vachon644

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Nov 27, 2011
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I know that the Susuki RM125 motocross uses a 10x14x15 bearing however it's not an open-cage bearing; the needles of the bearing are only seen from the inside. I don't know if that would fit but I recall that someone here has used this type of bearing in his chinagirl sucessfully. There surely is a susuki dealership near you that can order the part for you if you give them the part number.
 
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vachon644

New Member
Nov 27, 2011
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Quebec city, QC, Canada
Toadmund said:
That's a real nice bearing, but:
http://www.ebay.ca/itm/SUZUKI-RM125-RM-125-88-09-Piston-Wrist-Pin-Bearing-/400300485300?pt=Motorcycles_Parts_Accessories&hash=item5d33c4aab4
A big but, it's 15x19x20mm according to this seller.

PS, this is a non-drawn cup bearing.
A think you meant a different Suzuki model?
Click to expand...
http://www.motosport.com/dirtbike/o...TCH-(MODEL-K1)/BEARING-(10X14X15)/09263-10007

Aah! The 10x14x15 bearing I found is actually located in the clutch and not in the small end of the crankshaft. I would not use it that being said. A bearing of high quality such as the Stage6 one will probably outlast the engine (except in case of a catastrophic failure) and you could just reuse it since the wear will probably be minimal even after quite some mileage because these bearings are designed to run at rpms as high as 15'000 continually (thanks to the CVT scooters have) which the china girls won't ever go up to.. 10'000 rpm at best. I would either go with a chinese one from your engine kit seller (if available), the same size as this chinese one from a well known manufacturer (SKF, NTK, etc) or the Stage6 expensive bearing...
 
Toadmund

Toadmund

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Jan 19, 2012
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Saint John, New Brunswick, Canada
It's the Chinese bearing I want to replace, but you may be right.
The real problem is the bearing wandering that increases stress on it, not so much the quality of the bearing, IMO.

When summer is over, I am going to tear down my motor, or at least the top end, put a better bearing in and remedy the wandering problem with some sort of spacers between the bosses :confused: and the bearing.
 
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ivan H

Member
Oct 8, 2011
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australia
I just did a search of NTN bearings & they do a 10x14x16 that I'm pretty sure will fit, I'll get the calipers & measure between the piston pin bosses when I get home in couple of hours. I've got NTN main & countershaft bearings & they're good. If it fits I'll upgrade to as even with 10x14x15 there's still a fair bit of sideways movement, so I think it'll fit. Cheers
 
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ivan H

Member
Oct 8, 2011
622
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australia
Same, for bearings I just phone or drop in to the local bearing suppliers (& it's not in a large town or city), they will get any bearing they dont have in stock flown in from anywhere in Australia, no charge & its there next day, & their prices are good. Cheers
 
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ivan H

Member
Oct 8, 2011
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australia
Ok, I just measured between the bosses at 17.3mm so if there is a 10x14x17 available that would be the best option. Otherwise I'm going 2 grab one of the NTN 10x14x16 bearings & wack in there in the near future. No wonder the small ends fail in them, I mean the stock 10x14x13 is a low quality bearing to start with, & being able to drift so far its only like, 1/2 in the rod at extremes of travel. Cheers
 
Toadmund

Toadmund

New Member
Jan 19, 2012
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Saint John, New Brunswick, Canada
When I went to the bearing place, I specified an IKO 10x14x15 or something similar.
The guy looked it up and said it must be a proprietary part, he could not find it.

I think I will go back and try for the NTN 10x14x16 like you mentioned, failing that, I will ask for the 10x14x13 and use spacers, if no 10x14x13, I will go to the Stihl dealer and get the 'p/n 9512 535 2340' which is 10x14x13.

Thanks.

To add:
I wonder if anyone has an opinion on this;
If I install a longer bearing, would the extra weight affect the balance of the piston causing more vibration, or would it be so miniscule as to not even be something to worry about?
 
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