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Post Info TOPIC: Bottom end bearings


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Bottom end bearings
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Hi there,

 

I am in the process of repairing the bearings in my crank cases whilst it is apart. I have used the oven to remove all bearing and replaced most of them however there are two which I am not sure about. I have tried getting my head around codes but I'm making no progress.

I have 2no. I am looking for.

 

1)Koyo 83c107, black, sealed on one side, smallest bearing.

2)Koyo 6203DLAB, red, sealed on one side, 39mm outer, 17mm inner.

I purchased the following one but I'm unsure as the outer and inner walls look thicker so surely the ball bearings are smaller?

3)Koyo 6203DU

 

I have searched online and cant find an exact match. Has anyone else had the problem and resolved it?

 

Can't wait to build the engine up now!

 

Thanks 

 

 

 

 



-- Edited by dlee22 on Wednesday 30th of October 2019 08:58:33 PM



-- Edited by dlee22 on Wednesday 30th of October 2019 08:59:48 PM

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Thanks

Daniel Lee



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Hi Dan

when I was doing mine I found that 2 bearings are only available from Yamaha and they cost quite a bit



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Oh no!!

I best look on csmnl or somewhere too then!

Thanks

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Daniel Lee



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I rebuilt mine didn't do the crank or balencer but the gear box bearings were of the shelf at the local besting shop cant recall the sizes 



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Hi ttboof,

I didnt think about going to a shop, I instinctively go online now

I went to one this morning and they replaced them no problem!

Cheers for your help!

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Daniel Lee



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Old skool!

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I tried my local bearing company and they could not match it, so well done, please post us a link to your bearing supplier smile



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http://www.midcoastbearings.com.au/

They have been around forever and know their stuff 



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I went to Transpower Drives Ltd, Wellingborough, Northamptonshire, UK.

It wasnt an exact match for codes but same application and sizes etc.

Hopefully it holds out as the engine is back together now :)

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Daniel Lee



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Sounds like they did the same as my local guy 

They will be OK maybe even a bit better as the ttr gearbox speed and loads arnt a tough job  from memory they are the same as a lot of alternator .pulley ect bearings I used in my auto elect days 

I did ask if I should take the rubber seals out to be more like the originals they insisted I leave the seals in as they are pre lubed and over time oil will work it's way in 

 

 



-- Edited by ttboof on Monday 4th of November 2019 07:16:08 AM

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I would take the seals out if that's how the originals are. Oil is a better lubricant than grease, and will also help with heat transfer, but it shouldn't do any harm.

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plus one on that one

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I kept the side where the butted the casing edge on and remove the exposed side as per the ones I replaced :)

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Daniel Lee

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