What sprocket to use on a MS660 for stump work?

[Mark71gtx]

What pin sprocket would you suggest for stump work on a stock MS660? I work on saws for a local tree company and they have two MS660's. I have completely rebuilt one of them and the other I have put a new top end on it. The one I completely rebuilt has one of the more experienced fellers swearing I ported it because it runs so well and cuts like crazy compared to the other one. They are both in for servicing now and I noticed that the "hot rod" has an 8pin sprocket, while the one that gets no love has a 7 pin. Both are 3/8" and both saws wear 36" bars. Should I put 8 pin sprockets on both saws and see how it goes?

 

[Brewz]

Fast is good for fun or youtube vids, but cutting stumps all day, I would go with the 7 Pin.
Less stress on the saw, clutch, sprocket, the chain and the user when cutting for long periods.
It might cut a couple seconds slower but will have more torque and wont stretch the chains as much.

I guess if the saw is a good runner and pulls the 8 pin well, run it if your happy with it.

Have you opened up the mufflers? Chopped the baffles out?
That makes a BIG difference to these saws.
makes them really loud though

 

[Mark71gtx]

There is a an aftermarket dual outlet muffler on one of them, the other is bone stock. I was thinking the 7 pin would be the way to go for longevity, but wanted a second opinion.

 

[Canadian farm boy]

IMO I'd be putting a 7T rim on that saw. If it gets used for stumping and wears a 36" bar a 7T rim would be best.
Now if the saw occasionally wears a 25" bar or smaller I'd be tempted to try it with a 8T.

Just my $.02

 

[Mark71gtx]

Always 36"

 

[Brewz]

I run an 8 pin with my 25" bars on my 066's. It does that easy, even with 404 chain.

30" will run 8 pin well with 3/8 chain but is far more comfortable and lower stress with a 7 pin.

A 660 will love having the baffle cut out and the openings taken as far as you can.
The better they breathe the better they go, just wear hearing protection

 

[DELETED (Struggle)]

Flushing stumps always gets the chains dull fast so 7 pin.As you know a 3 pin wouldn't be any better if it was possibly to force a dull chain around so a 8 pin on a dull chain is even worse.


Sent from somewhere

 

[Moparmyway]

I cut stumps, mostly hardwoods
I've found my 066's and 661 love 404 with a 7 tooth and the 36" setup

3/8's dulls too fast to be a viable option with stump cutting

See if you can get an exhaust exit on the starter side to help get the exhaust and heat away from cooking the saw and the hands of the operator
@Red97 makes perfect deflectors

 

[Mark71gtx]

Not my saws. I can recommend, but that is all. I will pass along the word though.

 

[Chainsaw Jim]

So you basically have a magnum vs a stock saw. No wonder they think it's ported because it technically is....dual ported muffler.

 

[Mark71gtx]

I just put the dual port muffler on it. The accolades came before that install. Both saws claim to be Magnum's.

 

[Chainsaw Jim]

You think they were happy then. They're really gonna like it now.

 

[Mark71gtx]

As long as it wasn't the chain speed that had him all worked up!

 

[Chainsaw Jim]

Oh it was for sure, but now it's going to maintain that speed better under load in bigger wood...even with a 7 pin.

 

[Moparmyway]

Oh it was for sure, but now it's going to maintain that speed better under load in bigger wood...even with a 7 pin.

A 7 tooth 404 is about the same size as an 8 tooth 375

 

[jmssaws]

7pin for work 8pin for play.
Lots of saws can work with long bars with a 8pin but a 7pin is much more forgiving.
Easier on parts and the operator

 

[Chainsaw Jim]

A 7 tooth 404 is about the same size as an 8 tooth 375

Oh yeah!? Well your muffler screen ain't legal in my state.

Even if he does maintain the sprocket size by jumping chain gauge it'll still rip chit up more with the better muffler.

 

[stihl saws]

Only a 7 tooth for my 660 stumping with a long bar.

 

[DELETED (Struggle)]

Most of the stumps I flush I do use an MS880 just for the reason being more grunt and .404 chain.


Sent from somewhere

 

[Moparmyway]

Oh yeah!? Well your muffler screen ain't legal in my state.

Yup, shoot, it ain't legal in my state either