Stihl 044 12mm port iming question

[ft. churchill]

So I bought a Stihl that looked nice, run well and cylinder looked good thru the spark plug hole. I got it home and tried it out and was not impressed. I found the squish at .057" and the compression only at 118 psi. I did muff mod and no improvement, just louder. I pulled the jug off and the piston, rings and cylinder are perfect. That's when I found two base gaskets totaling .037" under the jug. So let me have it with your feed back on what numbers work well for you on the Stihl 12mm 044.
Here' the numbers I pulled with a degree wheel using no gaskets.
Intake closes at 78* atdc measured 148* duration.
Exhaust opens at 105* atdc measured 155* duration.
Transfers opens at 128* atdc 23* blow down.
Squish is .020" with no gasket.

 

[Trx250r180]

have you checked compression without the base gasket ? i think my 044 is at 170 or so psi without one ,i am not sure what timing #s are in it ,it is an early 10mm saw though

 

[ft. churchill]

No I have not, It's torn down and on the bench without rings so I can port it. I'm noticing the difference between the 10mm saw and it's smaller d-shaped combustion chamber (from pictures), and the larger round shape of the 12mm chamber. I'm going to throw some new rings on it as well. My porting is going to stay stock for now, I've already polished out the exhaust port, cleaned up the intake, (it had a burr or lip and a somewhat asymmetrical shape because of the burr on the lower edge of the intake.) I sure didn't remove any material as I don't want to lower that port any more. I think I calculated 177 theoretical psi with the squish at .020" and the port timing numbers are close to my Husky 70cc saws, except a shorter exhaust duration and longer blow down both of which should help torque. I have not checked timing since I cleaned up the ports last night, I'm putting together a horse stable today.

 

[one.man.band]

bump

sounds like a fun project. good luck with both your builds: motor and stable.

-omb

 

[ft. churchill]

Stable is almost done, only 1/2 of the roof to go. Battery died so it's in the house for pancakes, bacon and eggs. I just gave the two Catahoula leopard dogs booster shots for all the nasty stuff dogs can get, and wired in two fluorescent light fixture in the garage so I can work on saws after dark.
Now for the 044, damn it if the upper vibration mount isn't wrong. The dealer is closed and I'll have to wait. Maybe I can put the jug and intake on later. I'm still looking for timing numbers to compare mine against.