Stihl 661 porting/big bore info

[Scott Kelsey]

Hi everyone. I have been doing some reading, and although used the search function here I don't ever seem to find a lot of info on the subjects I am searching (I believe its a "me" thing). I am hoping to get some info, opinions, etc. I have a Stihl 661 M-Tronic. I have a desire to possibly have it ported and a big bore done if possible. I know very little about these operations. The saw does not have what I would say to be a lot of run time. Is porting worth it? Are big bores possible on the stock cylinder? I see a 58mm Wiseco big bore piston on Ebay, but do not know if it will work in this application or what it would put the cc at. Any opinions and advice is greatly appreciated.

 

[jacob j.]

I think in order to get a big bore, you'd have to have an OEM cylinder honed out and re-plated which can run into $$. I've not seen an off-the-shelf big bore cylinder available.

Those motors take well to porting and pretty much all of our builders have souped up 661s at one point or another, so there's no real way you could go wrong there. I've only
run one ported 661 and it was very strong. I'd be happy to cut timber with one.

 

[Scott Kelsey]

Thanks for the reply Jacob.

 

[Moparmyway]

 

[Sagebrush33]

Awesome performer.
Now that's what I call a pocket knife.

 

[Kiwioilboiler]

Scott the inbuilt search function doesn't seem to work very well at all.

Try googling your search terms or variations followed by 'site colon peforum.com' where the blue face is an o ie

Stihl 661 porting/big bore info sitepeforum.com

 

[Mastermind]

Porting a chainsaw? How silly.

 

[Stump Shot]

Porting a chainsaw? How silly.

Harrumph!

 

[Sawrain]

With the performance people on this forum are extracting from the 661 while still using the original piston, I would not bother looking at big bore options unless you had an immense desire to go down that path.

I can attest that a standard bore size Tree Monkey worked 661 will give you the full ported chainsaw experience.

 

[Woodslasher]

Scott the inbuilt search function doesn't seem to work very well at all.

Try googling your search terms or variations followed by 'sitepeforum.com' where the blue face is an o ie

Stihl 661 porting/big bore info sitepeforum.com

Yer not on AS anymore buddy, you can actually type opeforum in your posts over here without it getting blocked!

 

[Kiwioilboiler]

Yer not on AS anymore buddy, you can actually type opeforum in your posts over here without it getting blocked!

Tell opeforum code writers buddy, that copy and paste transformed itself.

 

[Woodslasher]

Stihl 661 porting/big bore info sitepeforum.com

 

[Woodslasher]

Well I'll be doggone! Odd.

 

[Kiwioilboiler]

Well I'll be doggone! Odd.

Apology accepted.

 

[Woodslasher]

Apology accepted.

I didn't want to stay on your bad side, pretty soon you'd be pointing out discrepancies in my pics and poof! I'd be banned! Fortunately I sold my 346 a long time ago so I've dodged that bullet for now.....

 

[Eduardo K]

That bar is way too big for that saw.