Rod and Main bearings

[fixkick]

I'm reading in the FSM about how the crank has different sized bores and journals.................

1. Ensure main bearing caps are numbered for location and arrow on cap points toward timing belt end of
crankshaft.
2. Cylinder block main bearing bore size is indicated by a letter "A", "B" or "C" stamped on cylinder
block. See Fig 9. Ensure main bearing bore is within specification. See MAIN BEARING BORE
SPECIFICATIONS table.
3. Crankshaft main bearing journal size is indicated by numerical size mark located on crankshaft
counterweight end. See Fig 10. Ensure main bearing journal is within specification. See MAIN
BEARING JOURNAL DIAMETER SPECIFICATIONS table.
4. If main bearing journal and main bearing bore are within specification, replace main bearings with
original size grade (color code). If color code on original bearing cannot be obtained, use size mark
letter on cylinder block and number on crankshaft to determine proper size main bearing to be used.
See MAIN BEARING SELECTION (STANDARD BEARINGS) table. Standard bearing thickness is
as listed. See BEARING THICKNESS SPECIFICATIONS table.
5. Main bearings are available in .010" (.25 mm) undersize. Undersize bearings are coded with 2 color
code marks. See Fig 11 and Fig 12 . Undersize bearings


If I'm reading all of this correctly it sounds similar to the "gang boring" done to the cylinders in that all of the crank journals are not necessarily the same size and each needs a bearing that matches whatever size the each of the journals actually are. Is this because the inside diameter of each of the cranks 5 bores in the block could be different? Were the blocks not line bored by the factory so that all 5 bores are in line and the same size?  

Here's my question, if I have my machine shop grind and polish the crank .010 do I also need to get the block line bored so all of the bores are the same size and will work with aftermarket .010 undersized bearings or do I need to find these color coded bearings that are specific to each of the 3 possible crank bores?

that is correct it was gang bored in the factory and same with cranks done ganged and is very crude this. 1989 is long ago. there are old videos of this and super scary to watch.

gang bored means 4 cutters, all with different wear,  and not the same, it is fast cheap way, and suzuki is all about cheap production costs. and machines.

after market (go to any usa machine shop and watch for 1 hour) I spent half a day here watching my block and crank getting machined ,last time.  
the guy on my crank used the calipers like 5 or more times as he did that, to my crank then use mirco polished journal  tools.  amazing perfect sized at the end . $5 extra charge micro.
real shop:
the cranks and bores of blocks are bore then precision honed by humans 1 by1  bore or journal. never ganged.
that means new after market bearings fit, (ring and pistons too) that do not have this huge list of wild odd sizes, as OEM did.

all machine shops know that.
they mic it all and tell you , see this is a stock engine with queer parts. ; we cure that now.
gone now. (this is not japan nor is it OEM suzuki it is a real USA machine shop) after mic, is done that order hot standard oversized parts, due top knowing at this instant what they will end up at next, do to their skills and a mic.
and real parts with normal perfect sized parts fitted.  (or racing set  losers)
They do a fantastic job of it.

good luck machining.