That is typical, even when stock. The 441 does the same thing.
Stihl MS661 Chainsaw Very First Cuts:
Stihl MS661 Chainsaw Very First Cuts:
It's here!!!!............Inside the MS661
- Thread starter blsnelling
- Start date
Help Support Arborist Forum:
- Status
porsche965
Addicted to ArboristSite
Hi Brad,
Are you running the winter/summer shutter open or closed?
Are you running the winter/summer shutter open or closed?
Mastermind
Work Saw Specialist
Looks like that saw needs the squish cut.
Why would I want to go and mess with what already works very well? Both compression and port timing are right where I like them. I see no advantage to cutting the squishband in this case. This saw isn't like a 660 that needs the exhaust port lowered. I'm very pleased with how these saws are turning out.
Mastermind
Work Saw Specialist
Just messing with you Bradley.
I'm not liking the intake after any machine work, popup, or cut squish.
I'm not liking the intake after any machine work, popup, or cut squish.
Four Paws
Addicted to ArboristSite
Any options for an alternate piston with a longer skirt?
Mastermind
Work Saw Specialist
You seem to think the same timing numbers work well in every saw......I don't see it that way.
We just have different ideas about what a real world work saw is I suppose.
Peace?
We just have different ideas about what a real world work saw is I suppose.
Peace?
Mastermind
Work Saw Specialist
Adding to the skirt would be a great thing from where I see things.......but would it hold up?????
At this time some filler in the intake is the only solution I'm seeing.
spencerpaving
ArboristSite Guru
Just curious...what are ya getting for compression?
Mastermind
Work Saw Specialist
Not as much as I wanna get. You?
Four Paws
Addicted to ArboristSite
I wasn't implying welding it up...possible but you need an expert on the TIG. Then some machine work, potentially destroy the piston during either process.
You will know soon enough how the filled jug performs with a shorter intake duration. If it works, no reason you couldn't look for a piston from a different saw that would swap? If you could find something with more skirt length or more compression height, or both, you will have a lot more to work with. Selling the OEM piston would recoup some/all of the cost.
Are these 661s using a 54mm or 56mm bore?
Mastermind
Work Saw Specialist
56mm......
But the piston is pretty "different".
I'm looking at a 395XP piston now......
But the piston is pretty "different".
I'm looking at a 395XP piston now......
I know
. I thought that I'd go ahead and give a real answer though.
Mastermind
Work Saw Specialist
I know
Quit picking on me dammit.
I'm sensitive.
About 180 I'm cool with that. I like 180-190, 200 max.
Mastermind
Work Saw Specialist
I think the 395 piston might just work.
Brad, if I get this intake timing down some.......you be eating my dust again.
Brad, if I get this intake timing down some.......you be eating my dust again.
Not the case at all. Where did you get that idea? There are saws that I would never use a low intake. Others respond very favorably. Some saws love a short blowdown, others not do much. I look at every saw as an individual. I actually cut the squishband and a 660. IMHO, most saws don't need it. In those cases, AFAIC, it's simply a matter of personal preference and build style.
I don't mind the low intake on this saw at all. I am curious to see how Randy's R&D saw responds. I would personally hate to think I had to epoxy a work saw to make it run like I like.
Four Paws
Addicted to ArboristSite
Understood.
Right on! I like pushing the envelope...any problem can be solved, it is just finding the best solution.
Is the wrist pin 13mm? 56mm is a popular dirt bike bore for the 123cc bikes. The 2100 used a 56mm bore, too I think. And the 056 mag2.
That would be cool. However, I'm not seeing this universal rule of 40° of primary compression. I've seen too many saws that run stronger when breaking that rule. Others run best like that. I just don't see trying to apply it universally. Again, every saw is an entity unto itself, and built accordingly.I think the 395 piston might just work.
Brad, if I get this intake timing down some.......you be eating my dust again.
- Status
