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Oversize Crank Bearing Question


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#1 duffdub

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Posted 25 July 2020 - 02:54 AM

I dropped my A+ 1275 crank off at the machine shop to be reground. The main journals measure at about 2.010”. I’ve read they can measure 2.005” to 2.010”. Why is this this? Wouldn’t that mean new oversize bearings may not fit? Or does the 0.005 difference not matter? Hope my question makes sense.

#2 GraemeC

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Posted 25 July 2020 - 06:06 AM

2.005”-2.010” is the dimension with a given tolerance - if it was an exact figure it would be harder to achieve and hence MUCH more expensive.

If it is being reground, the machine shop will advise the bearing size needed.



#3 duffdub

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Posted 25 July 2020 - 06:28 AM

2.005”-2.010” is the dimension with a given tolerance - if it was an exact figure it would be harder to achieve and hence MUCH more expensive.

If it is being reground, the machine shop will advise the bearing size needed.


Okay thank you

#4 Moke Spider

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Posted 25 July 2020 - 07:01 AM

Might have the decimal point in the wrong place there guys.

 

The Std Mains on a pre-A+ 1275 are 2.001 to 2.0025".

 

A+ 1275 is 2.0011 to 2.0017".



#5 duffdub

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Posted 25 July 2020 - 07:40 AM

Might have the decimal point in the wrong place there guys.

The Std Mains on a pre-A+ 1275 are 2.001 to 2.0025".

A+ 1275 is 2.0011 to 2.0017".


Oh I left some 0’s out. Thank you for the correction




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