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?

 

what is the stroke?

 

total volume or displacement
pi x radius squared x stroke

doing it in mm gives you a big number just take the first three numbers
if it had 70mm stroke the displacment with the 86 mm piston would be
406.6 cc
ok wiseco online lays it all out for you. it has a 70 mm stroke they call a 86mm 407 and a 87 mm 416cc