Sprocket size questions

[josharb87]

Am i right in thinking a larger sprocket will increase chainspeed, but decrease torqueyness?

if correct a shorter bar will benifit from a larger sprocket, but a longer bar will benifit from a smaller sprocket yes?

 

What sprocket will suit an 880 best with 36inch bar, what sprocket for 50inch bar?

 

Same question with a wojo style muffler mod?

[Charlieh]

is the 880 on .404 or 3/8?

[josharb87]

.404, rollomatic bar, standard saw

[Charlieh]

i run an 8pin on mine just makes it quicker on 36" with no loss in torque. Any bigger than 8pin you need to start modifying the tail on the bars to allow for a larger sproket! so i would consider that the upper limit without pratting about with bars etc, you can then also have issues with the chain entering onto the bar groove if you go any bigger.

 

also it will be dam tight getting a new chain on, be prepared for a bit of screwdrivering to get it all on

[josharb87]

Thanks Charlie, am i right in my other assumptions? What about 50inch, down to 7?

[Charlieh]

if you have the full bar burried then probably yes, but i have only run my upto 36" and it certainly doesnt loose any torque on that, so i would say see how you get on try the 8pin on it,

 

one thing i didnt mention the bigger issue with increased chain speed is chip clearance from the cut i noticed on mine since going to full compliment of cutters from a couple of loops of semi skip that i got with it, it can pack the cut up with sawdust very quickly

[Rob D]

I think the 8 pin is fine to use on a 50" bar (that's what I'm using) but then maybe if the woods hard and the saw is bogging down you could switch to an 7 pin. But it depends a lot on the wood and how the chain is cutting.

 

With an 8 pin if the chain is super sharp it gets up to speed and stays there regardless but if the depth guages are set a little low/uneven the chain bogs a bit easier.

 

It's hard to tell unless you spent a day experimenting.

[Rob D]

 

Same question with a wojo style muffler mod?

 

 

I have a wojo style muffler and it was superb on my old 880. Not that much louder and I'd say a 15% to 20% increase in power.

 

But one day I had a milling job far away, was using skip link full chisel ripping chain, in a bit of a rush reduced the depth guages too much. This caused big vibration. But I carried on and milled the tree..... (was a couple of years ago)

 

The increased power meant the vibration was greater and it caused a hairline crack in the crankshaft.

 

An expensive lesson but I got a new 880 only to see they'd changed the muffler! So I still have the wojo one which I'll sell for £120-00 inc vat. Bear in mind a new Stihl muffler is £259-00 + vat.

 

This has helped with me becoming more obsessive about chain sharpening!

[Mike Hill]

Sharpening the Chain with the File pointing down will make more of a difference with longer Bars than what size Sprocket you are using.

 

A longer Gullet on the Tooth means the Tooth has more room to "Coil" the Chip coming from the Cut.Try it.

[Rob D]

Sharpening the Chain with the File pointing down will make more of a difference with longer Bars than what size Sprocket you are using.

 

A longer Gullet on the Tooth means the Tooth has more room to "Coil" the Chip coming from the Cut.Try it.

 

 

Have to say I've not heard of that before.... I can't quite picture how the file pointing down would give that much longer a gullet to effect how the chip came out of the cut... can you put up any pics to illustrate?