Chain Speed/sprocket change

[hal9000]

I read somewhere recently that for small logs, chain speed is more important than power (which makes sense). I don't cut anything over 14" diameter or so, and deal almost exclusively with softwoods like Aspen and Pine....

Is there any reason that I shouldn't put an 8 tooth sprocket on my MS390? Are there any disadvantages that I need to take into account?

Thanks all

 

[jackjcc]

That should work out for you, keep the rpms up and the rakers down. If you lean on it you will stall the chain easier with the 8 pin.


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[HarleyT]

Get a rim sprocket setup, and get both rims and try it out.

 

[hal9000]

Get a rim sprocket setup, and get both rims and try it out.

Thanks for the quick responses....

Mine's already a rim sprocket setup, but it's the small 7. To go to 8T I'll need to swap drums. No big deal, but if the swap isn't worth it it does add a few more dollars to the "oh well" pile.

On that note, does anybody know off the top of their head which standard 7 drum will fit the ms390? I know oregon makes one (P/N 34162 ), but not sure if there's a stock item off another saw that I can look for as well?

 

[rd35]

Hmmm! I could've sworn I had an 8-tooth sprocket on the shelf for my small spline drum. I'll check when I get home.

 

[hal9000]

If it turns out that you do, please let me know if you can find a manufacturer & P/N. Oregon doesn't list one and I haven't found an OEM type anywhere online yet.

Replacement drums are inexpensive enough that it won't be a big deal to swap. But if I can run what I have, I will.

 

[rd35]

.325 pitch or 3/8? Sorry I forgot to ask. My 8-tooth is .325

 

[blsnelling]

I highly recommend you stick with a 7-pin on any 60cc saw.

 

[SawTroll]

There is nothing wrong with testing the options - rims usually are cheap.

However, there hardly is much point in trying 3/8"x8 on that saw.

 

[HuskStihl]

I highly recommend you stick with a 7-pin on any 60cc saw.

That would normally be good advice, but this is an MS390 we're talking about. I've read they will pull a 28" full comp in oak all day. Torque of a diesel dually in one bad-ass little package!

 

[SawTroll]

That would normally be good advice, but this is an MS390 we're talking about. I've read they will pull a 28" full comp in oak all day. Torque of a diesel dually in one bad-ass little package!

Then your hearing isn't much good, as you obviously heard wrong!

 

[undee70ss]

I highly recommend you stick with a 7-pin on any 60cc saw.

What would be the minimum cc and bar length to consider a 8 pin, with 3/8 pitch chain?

 

[blsnelling]

A ported 70cc class saw would be the bare minimum IMHO. I've seen a lot of ported 90cc saws that were still faster with a 7-pin.

 

[wde_1978]

As has been said, try it and decide for Yourself!

I don't like the 8pin on my PS-7900 (79cc) with a 20" 3/8" B&C setup as a permanent work setup - but I am mostly bucking oak and beech tree trunks.
For reference, my PS-7900 is able to pull a full comp 36" 3/8" chisel tooth B&C setup buried in a walnut root ball - that been said, the power to pull a 8pin is there but the benefits (in hardwood) are not.

A larger diameter sprocket will increase wear of chain tie straps and bar rails, as well as reduce lubing as the faster moving chain will fling off more oil at the bar tip.

I think that a 8pin is making for a fun-to-play-with setup, but I wouldn't recommend it as a permanent work setup!
Just my humble opinion, each to his own.

Have fun experimenting.

And as we all love pictures:

 

[Ryan'smilling]

I put an 8 pin on my ms460 with a 20" B&C. I took it off shortly thereafter. I just didn't like that it was easier to stall. If I was cutting small softwoods exclusively, then I'd keep it on there. I think in your case, if that's all you're doing it'd be worth a try. Especially if you've got the logs in a nice bunk-type situation where your bar isn't getting pinched or bound regularly.

 

[Huskybill]

The bar length plus the size of the wood dictates what sprocket size to use. I run a 2100(99cc) saw with a 8 tooth sprocket and 404” chain, a 16” bar. She destroys 15” hardwoods. after running the 2100’s for many years I had arms like Popeyes. The forest was my gym.

This was my race saw setup for the local fairs. I took it in the forest to work. Great saw to run in ten degree weather. A cord of standing hardwood on the ground bucked up in 50 minutes.