Ok,
heres some info.
first look up mc10 heaven in this forum.
just plug mc10 heaven in the search function to find.
the bottom four are complete saw clones.
the top right hand motor is a mc10 block with saw parts added.
i know this from a little bird in my ear!!!
normally i'd tell you read everything written in the forums about mc10's and leave the rest to you.
i will advise doing this anyway but i am bored tonight so i'll write a abbriviated tutorial.
in years past i've advised people looking up the numbers and figuring out the interchanges themselves.
i was building a bunch of mc10 clones and spent months/years figuring out all this stuff.
below is info i gathered that i've never let out before but i have a few mc10's now sooooo.
FIRST:
the d44 block will be useless please send to Rick Chapman as he makes trophies out of them and donates them for vintage races.
it won't work as a decent kart motor and for this info that's all i'll ask you to do.
what you need.
mcd44 saw unmolested and either a 1-70 , 1-80, s44a, s55a saw
i've bought these motors for as much as 250$ all the way down to 10$.
if you're patient you can save money.
from the d44
you keep the center plug head , shroud,correct outer cover,flywheel,coil and inner shroud.
the conn rod bearings are useful save those though there will only be 22.
the rest either scrap or give to a chainsaw forum guy to reuse.
use only the 1-70 , 1-80, s44a, s55a saw
do not use any motor that's not listed the higher number 1-71 1-72 1-81 1-82 WILL NOT WORK RIGHT.
the cranks and points are different.
from the 1-70 , 1-80, s44a, s55a saw
take the inner powerhead = block, crank,conn rod and piston
the head ,outer fan cover and coil remove you can sell as a mc super series parts.
the inner cover and flywheel are usually mc10 type.
if you're wanting to now would be when you modify the block.
most port mods will make a mc10 a smudge faster without hurting durability.
if you've never modified a port and want to learn use the d44 block for practice.
you can freshen the existing piston with new rings and quick hone if bore is good.
you'll have a early style mc10 with fat rings.
option #2
Teds saw piston ring modification:
carefully cut a slot in the center about halfway through the thickness in the top ring of the piston.
using a thin dremel cut off set in a drill press you go around the whole radius of the ring dead center.
a steady hand and extreme care is needed or things get real exciting.
the purpose is to mimic two stacked thin piston rings as if they were in the same ring land.
heat up the other low ring till it gets red and let cool this will break it's spring temper and make it soft.
put the soft ring low modified ring in top land.
option#3
buy a thin ring mcculloch kart piston.
it MUST be for a mc10 or the port timing will be wrong.
finally replace all the bearings and seals.
they are commonly available and cheap insurance.
paint whatever color you want have fun.
dave