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Discussion Starter · #1 ·
I'm trying to figure out 400ex bore info.

If I have a 400ex and bore it from the stock 85mm to 86mm.
is that considered a 416 bore?

and if i have it bored to 87mm.
is that considered 426 bore?
 

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Talk to moose.He knows the math.
 

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Discussion Starter · #3 ·
Standard bore- 397cc or 85mm
402cc- .040 over or 86mm
406cc- .060 ever or 86.5mm
416cc- .080 over or 87mm
426cc- .120 over or 88mm
440cc- .160 over or 89mm
also...
440cc with an extra 4mm stroke = 460cc
416cc with an extra 4mm stroke = 440cc

Is this correct for a 400ex?
 

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That sounds about right.
 

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Looks right to me!
 
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