Chainsaw porting

[jmac]

19 hours ago, spudulike said:

Yes, there are guidelines as to how large ports can be made, restrictive elements that can limit port size, minimum clearances piston to squish etc. I learnt some by looking online, some from reading a couple of books that I purchased and some by just developing my own techniques.

Just use a dremel with a carbide burr or diamond burrs for lighter work.

You can't put metal back on once you have ground it off so don't just think "wider the better" as many seem to think.

Good on you spud ? nice to see a professional porter giving advice to someone who wants to have a crack at it themselves. 

[CutterSy]

What saw is it that you are wanting to port?
I feel I should warn you, porting saws is addictive, once you go down this rabbit hole running a stock saw is just boring!
Its a good plan to just smooth out the ports first to get a feel for it, do a muffler mod as well. You will see gains from just that.
If you let us know what saw you’re planning to port I can help you with any knowledge I have of it.

[Snedding_J]

18 hours ago, Wonky said:

it’s a start

Gordons book

http://www.amrca.com/tech/tuners.pdf

 

and google mcdizzy,, maybe I’d better point you 

 

MacDizzy's Two Stroke Technology Exchange - TRX - YFS - YFZ - Glamis Sand Dunes

MACDIZZ.COM

---

Two Stroke Engine Technology Database, Large Two Stroke engine building / porting section. Visit the Glamis...

 

 

Cheers Wonky, really appreciate it. Will look it up ?

[Snedding_J]

5 hours ago, CutterSy said:

What saw is it that you are wanting to port?
I feel I should warn you, porting saws is addictive, once you go down this rabbit hole running a stock saw is just boring!
Its a good plan to just smooth out the ports first to get a feel for it, do a muffler mod as well. You will see gains from just that.
If you let us know what saw you’re planning to port I can help you with any knowledge I have of it.

Thanks CutterSy, I would like to port a Stihl ms461 and my Husky 560xp. I can imagine porting being quite addictive, a bit like always convincing yourself you need another saw! Any help and knowledge would be a great help. I'm new to the forum and it's been great having people get back to me with their knowledge and information - thanks again.

[CutterSy]

Both saws respond really well given the right treatment. 461 benefits from some ignition advance, the muffler is easy to do as well.
560 has transfer caps so you can easily work the upper transfers, be very careful with the intake as they can’t really be widened because of the piston skirt. The muffler is a bit more of a pain because it doesn’t separate like the 461, I just cut out as much of the baffle as possible and open up the exit.
Lots of info out there. Everyone does it slightly differently, the only way to see what works is to try and test.

[Snedding_J]

32 minutes ago, CutterSy said:

Both saws respond really well given the right treatment. 461 benefits from some ignition advance, the muffler is easy to do as well.
560 has transfer caps so you can easily work the upper transfers, be very careful with the intake as they can’t really be widened because of the piston skirt. The muffler is a bit more of a pain because it doesn’t separate like the 461, I just cut out as much of the baffle as possible and open up the exit.
Lots of info out there. Everyone does it slightly differently, the only way to see what works is to try and test.

All this info is great CutterSy, I've got a good bit of mechanical background but not on modifying 2 strokes.

 So on the stihl ms461, how would you advance the ignition? Alter the key on crankshaft/flywheel? Sorry for all the questions, just really keen to learn about porting chainsaws.

[Wonky]

Yeh also the 461 sans gasket... but you have to take the tops off a little on those 2 screws that hold the saddle in place,, ask if you don’t understand ?

[Snedding_J]

2 minutes ago, Wonky said:

Yeh also the 461 sans gasket... but you have to take the tops off a little on those 2 screws that hold the saddle in place,, ask if you don’t understand ?

Not quite sure I understand Wonky?

Cheers

[Wonky]

10 minutes ago, Snedding_J said:

All this info is great CutterSy, I've got a good bit of mechanical background but not on modifying 2 strokes.

 So on the stihl ms461, how would you advance the ignition? Alter the key on crankshaft/flywheel? Sorry for all the questions, just really keen to learn about porting chainsaws.

That’s all in the mcdizzy and the 2stroke t h book... to advance and how much is enough.... if you know fuel then the answer is never the same

[Snedding_J]

3 minutes ago, Wonky said:

That’s all in the mcdizzy and the 2stroke t h book... to advance and how much is enough.... if you know fuel then the answer is never the same

Will have to give mcdizzy a look. No two engines are the same. I may be picking your brains again bud ?