porting chainsaw

[burrell_]

what i want to no is there a link in showing me how to porting a saw or can someone run me though porting a saw with pic please.

as some off u no iv nearly built a steam train so porting a saw can be that hard can it and any help would be much appricated

cheers martin

[burrell_]

and whats big bore all about

[Mesterh]

Porting a saw isnt a very straight forward thing to do. You can easily wreck a cylinder by doing it wrong mate.

 

A muffler mod is an easier more straight forward option.

 

A big bore is where you increase the CC of the engine by buying an oversize cylinder and piston.

[rapidlee]

here are some ideas and some photos of muff mods

 

http://www.arboristsite.com/showthread.php?t=36541

[burrell_]

is porting making the exhaust port bigger

big bore would be to put the Cylinder head in me lathe or mill centre it up fly cut or centre bore the cylinder /bore out to what ever the over size piston ring is off the bore is that rite

[Mesterh]

is porting making the exhaust port bigger

big bore would be to put the Cylinder head in me lathe or mill centre it up fly cut or centre bore the cylinder /bore out to what ever the over size piston ring is off the bore is that rite

 

Porting is altering the size and shape of the ports exhaust, intake and transfer, not necessary all of them though.

 

This affects compression and port timing so it cant really just be done willy nilly ie making them bigger etc.

 

With a big bore you usually buy a new cylinder and piston kit that has been designed to increase the CC.

 

Or you might be able to fit the piston and cylinder from the next saw model up ie ms660 to a ms460, btw thats just a guess so dont go out and buy the above.

 

You cant really mill the cylinder as it is coated with nikasil I think rather than a steel liner like the older saws/2 stroke engines.

[burrell_]

rite im starting to understand where do i get cylinder and piston kit and exhaust modes form i take it with any mod u have to richin the fuel on the carb and also does the engine run cooler with the exhaust mod

[josharb87]

hey martin, im wanting the same answers as you!

 

take a look through this thread on the treehouse, good pics im sure an engineer like you can work from, cool videos too! they take a standard 880 and 460, test their performance, then start modding them, testing their performance as each mod is done, the end results are fantastic!

 

460 vs 880 cage match - The #1 HARDCORE arborist forum, bar, and grill - Enjoy the buffet and libations!

[MattyF]

They look good but it must put more stress on the bottom end??? ok as i race saw but dont think it would last long in a proper work enviroment...that 46 sings though!

there is loadds of stuff on the saw forum on arborsite if you can be bothered to sift through it....

I just want to know what squish is??!

[TimberCutterDartmoor]

Squish: The area between the piston crown at top-dead-centre and the cylinder head. Skimming the head used to be the classic way of reducing the squish to raise compression. Did it on a mini once - compression was so high it kept stalling! Might have been fuel choice tho.