Porting... Please help

[farmguywithasaw]

Forgive my ignorance, but isn't the general rule of thumb to raise the exhaust, and lower the intake? Rather then raising both of them? Or am I wrong?

Yeah you’re correct. However you are increasing duration on both

 

[J D]

Forgive my ignorance, but isn't the general rule of thumb to raise the exhaust, and lower the intake? Rather then raising both of them? Or am I wrong?

Yes.
As mentioned my "recepie" is conservative & doesn't effectively raise or lower anything by any more than you are dropping the cylinder to achieve better squish. There's nothing stopping you from raising the exhaust a bit more & not raising the intake any... it will give you a saw that rev's better at the expense of some torque.
This porting by no means gives you the biggest gains... but it's relatively straight forward, doesn't require a lathe or use of a degree wheel, will definitely provide good overall gains, & (most importantly) is pretty hard to significantly screw up

 

[NSEric]

I dont know what a ms440 needs porting wise.
I find every different saw needs different things done to it porting wise.
The 660 clone I ported needs transfer work but the timing numbers are where they need to be. I just add finger ports to them and they rip, you need to flip the piston to do this so dont grind on the exhaust port at all if adding finger ports to a stihl.
The zenoah 6200 clones just need the lower transfers opened up and the intake/exhaust widened, they get no extra duration.
The husky 359 I did needed the transfers and exhaust raised a few degrees to get some rpm out of it but the intake just got widened.
The troy built 42cc saw I just did needed everything tweaked. I raised the exhaust and transfers a bunch and lowered the intake to end up at 106 exhaust, 124 transfers and 77 intake.
I recommend the troy built/craftmans 42cc saws for porting as they're cheap and easy to port. It's a good running little saw when ported.

 

[262freak]

Do you have to have mills and lathes to do a proper porting job? Going by what one member said to measure your squish and take off that much off the cylinder. What if you don’t have a mill or lathe?

 

[J D]

Depends what your numbers are to start with & what you're aiming for. If you don't have the machinery I'd be inclined to do the best you can working within the limits of what you can adjust with the base gasket. Usually you can still achieve a fairly measurable result.
If you really wanted to, I'm sure squish band could be roughly cut with home made tools & finished with sandpaper glued to the top of a piston. Cylinder can be lowered by carefully sanding on a flat (usually glass) surface.
The sandpaper on glass trick works well for cleaning & evening up a cylinder base in general

 

[guym3]

I'd second the advice to watch everything that Tinman saws has to offer on youtube. He taught me a huge amount. Also you need to start stripping and rebuilding saws making minor mods as you go before you think of grinding upper transfers!! Starting with doing muffler mods, then improving air intakes is a good place. Then move onto base gasket delete (check squish isn't too low). Then when you're ready to grind, look at opening and improving flow into the lower transfers before you touch anything that the piston covers ie risk chipping plating.
Agree that a 440 isn't the place to start. Buy a few non-runners off ebay and get them going first. Porting is fun but can be a steep learning curve so one step at a time.

 

[NSEric]

I'd second the advice to watch everything that Tinman saws has to offer on youtube. He taught me a huge amount. Also you need to start stripping and rebuilding saws making minor mods as you go before you think of grinding upper transfers!! Starting with doing muffler mods, then improving air intakes is a good place. Then move onto base gasket delete (check squish isn't too low). Then when you're ready to grind, look at opening and improving flow into the lower transfers before you touch anything that the piston covers ie risk chipping plating.
Agree that a 440 isn't the place to start. Buy a few non-runners off ebay and get them going first. Porting is fun but can be a steep learning curve so one step at a time.

Tinman cant build a fast saw, I wouldnt copy one of his builds.
He makes the lower transfers huge and pretty which kills case compression.
The power gains on most saws are from upper transfer work and adding compression, the two things tinman doesnt do lol.