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main journal and crank pin bearing selection

Posted: Sat Apr 13, 2013 9:04 pm
by gsxridiot
getting ready to reassemble blown 600 motor with new crankcase halves
need help with plane bearing selection
case upper has numbers:
3HH 039275
first 6 numbers on crank are:
221222
manuel says to subtract respective crank #'s from case numbers
first issue, subtracting 2 from 0 ???
so i call that a #2 size bearing? ok
next issue:
9-1= 8, well there is no bearing sized at 8- stops at 5

bumming me out

crank pin issue:
rods have been polished, ink #'s on connecting rod caps are gone on all but 1 rod
and its # does not corrolate to what it is supposed to be, goes like this:
45EJ ... i knoe the "E" is to aid in alining the cap to the rod- not really an issue because the rods and caps have a detent for indexing the bearings, the problem is that the #'s are on the rod and not the cap- and there is two numbers- the "J" is where the sizing number should be stamped
i have a full selection of NOS plane bearings -all colors- but no way to know whitch to use

i beg for some assistance here, thanks
-eric

Re: main journal and crank pin bearing selection

Posted: Sat Apr 13, 2013 9:59 pm
by DonTZ125
I think you're reading the engine serial number. The journal numbers are on the back of the engine, under the mounting bolt lugs.

If you have no starting point with the con rods, you may have to use the brute force method:
  • install the rod with a bearing and some plastigauge
    remove the rod
    check the plastigauge measurement
    if in spec, that rod's done
    if not, go up or down as needed
    lather, rinse, repeat
This is why I really don't like Yamaha's 'we do the thinking for you' method. It shouldn't be that hard - measure the pin OD, measure the rod ID, determine the appropriate bearing thickness to get the necessary clearance, select bearing of the appropriate thickness ...

Re: main journal and crank pin bearing selection

Posted: Sat Apr 13, 2013 11:31 pm
by gsxridiot
"I think you're reading the engine serial number. The journal numbers are on the back of the engine, under the mounting bolt lugs."
um, well, duh! thanks for helping me pull my head out

ok, i understand the "brute force" method
the bearing part numbers look like this:

1WG-11656-00-00
1WG-11656-10-00
1WG-11656-20-00
1WG-11656-30-00

i assume that the "00" number is the thinnist and the "30" is the thickest
is this correct?
thanks again Mr TZ, i had my head spinning

Re: main journal and crank pin bearing selection

Posted: Sun Apr 14, 2013 12:44 am
by DonTZ125
I'm actually not sure of the relative thickness of each part number - grab one of each and measure! Actually, if you could measure and catalogue each of the rod and journal bearings, that would be a tremendous resource for the Wiki, and a great help for the next poor bugger in your position.

As for the reality check - no problem. I've received more than a few myself ... :whistle