porting and muffler add ons?

[symamania]

Gday guys,

This May have been already been covered or could even be a dumb question, But can you guys explain to me about porting and buying better exhausts to get more out of your big saws.

Can you still do this sort of thing for older saws say a Stihl 076 for example. Ive recently purchased one for CSM work and am wondering with its worth upgrading this big old saws for more power and the rest.

cheers

[ZeroJunk]

The 076 was made before EPA restrictions started choking them, so I don't know that a muffler mod would be much gain if any.

[symamania]

oh right fair enough what mods do you make to modern saws to get more power

[sharkey]

To change the compression ratio some will cut the 'squish band' at the combustion chamber whereas others will use a 'pop-up' piston.  Ports are then shaped for optimum flow.  The cylinder is then decked to set the squish.  Intakes and exhausts are opened for the same reasons.  You can do the work yourself if your highly motivated otherwise it would be best to send the saw out to someone who knows what theyre doing.   

Here are a couple of videos that will help you understand part of the process;
https://www.youtube.com/watch?v=t3Q6OsmMXEU
https://www.youtube.com/watch?v=oyuhi12zlp8 

[HolmenTree]

Can you still do this sort of thing for older saws say a Stihl 076 for example. Ive recently purchased one for CSM work and am wondering with its worth upgrading this big old saws for more power and the rest.

For CS milling work it's  not the best idea to raise  compression and do other  mods to the cylinder. Durability  can be compromised with long cuts milling with those  mods.
Muffler modding is OK though.

With my Stihl 090 for CSM I left the cylinder and piston stock....never had the cylinder  removed to date.
But the biggest gain I got in performance was disabling the speed governor anf made sure I kept an eye on the correct carburetor H and L setting.
I'm  not sure if your 076 has the same flywheel wind vane governor as my 090. But it would definitely be something  to look into.

[symamania]

Gday holemen what does removing the governor do and why did you do it

[HolmenTree]

Gday holemen what does removing the governor do and why did you do it

Disabling  the governor  makes the saw run its  full rpm potential  at wide open throttle,  making the most power . But great care is needed to not run the carburetor set too lean.
As I said  my 090 Stihl had a wind vane governor  operated by the wind off the flywheel  which  moved a rod and partially  closed  the carburetor  choke shutter. This made a rich condition  and kept the rpm in a low safe range.
Not sure if your 076 has the same style of governor  ...........