Help with modding 3120

[Lakeyboy89]

Hi all, I've reading and reading for weeks about sprucing up my 3120 (non EPA) I've collected all the bits I believe I need. Now I could just dow with some help putting it into action.

The saw will mostly be used for milling, but occasionally felling/cross cutting of oversized stems.

Milling I use a lo-pro setup which it pulls fine. I just want a little more poke out of it for felling and cross cutting.

I have an unlimited coil ready to go in, some micro drills to open the jet up if I need to, muff mod will happen also. If anything just to keep temp down when milling (can't hurt right?)

I am wanting to know how much the flywheel needs to be advanced to suit the coil. Also would I be able to get away with not rebroaching the flywheel, would the the taper hold it in place enough?

If there's any tips or ideas you guys have I would be incredibly grateful for your help.

 

[kneedeepinsaws]

For mine I use 40:1 in the summer and 50:1 in the winter with the stock jet. This variance in oil ratios for me was enough to have the saw running just right for tuning. The stock jet was rich at my 3500’ elevation
This will save you time and hassle drilling out the main jet. I would try this first before you start drilling and see what you think.

I found with the stock muffler and unlimited coil I did not have a problem with it overheating or running too lean milling.
To tell you the truth 9600rpm in which the stock could limits too was more than ample enough for the power curve while in the wood. The saw will not make power past this in wood without porting, at least mine didn’t. The only reason I changed the coil was because I hated the sound of the rev limiter. I will probably change it back at some point as the coil I am using is aftermarket.
This particular saw is heavy and cumbersome, in my opinion, it is strictly a work saw and doesn’t need a flashy unlimited coil or adjustable carb for milling. By the time you are done cutting slabs for 4 hours you aren’t gonna care about how it looks or sounds lol, your just gonna wanna get that fat pig back into the truck!!!!
I found bucking with the saw impractical given it’s weight, you wanna show your friends a wicked bucking saw grab the 395 as it is much more easy to handle than the 3120.

this saw is meant for two things, milling and redwood trees that justify a 42”+ bar.
If you use it outside of that your going to come to the same conclusion I have posted above eventually. However if you want to sex this thing up and it’s your pride and joy, go for it still is fun, for the first while

 

[Lakeyboy89]

Thankyou for the quick reply! Hands down I agree a 395 is a much better saw handling wise, used them a few times! I have 500i with west coast goodies running a 28 for almost all my felling needs (not much that It can't manage when double cutting in the UK really). I'd just like to give the 3120 a little more fun factor for when it does come out on the bigger jobs. Crosscutting a large beech stem a few weeks ago it felt absolutely gutless compared to my friends old battered 880 fulling the same length bar (42). I run aspen 4 mixed at 40:1 for milling already.

 

[Moparmyway]

Flywheel advance : What coil do you have on it now, black or green ?
If you need to advance it, its just about here ........


Carb : Send to Randy or Kevin to add the high jet, well worth every penny to have done

 

[Lakeyboy89]

I have the black coil installed from when I bought the saw. It's an older model. Thankyou for the pic that helps no end! What do you use yours for mostly? How does it perform with the mods?

 

[Normzilla]

Good post. I have a 3120 myself.

 

[davidwyby]

A ported adjustable H jet 3120 is something…

 

[srcarr52]

My ported 395 kept breaking my lo-pro milling chains. They were Carlton semi-chisel and I was cutting around 30" of red oak, running an 8 pin sprocket. I think Stihl lo-pro will hold up better but you might start breaking chains if you add much more power.

 

[Moparmyway]

I have the black coil installed from when I bought the saw. It's an older model. Thankyou for the pic that helps no end! What do you use yours for mostly? How does it perform with the mods?

If you already have the black coil, I believe you will not have to advance the flywheel.

I have to double check, I'm smart enough to know that I'm too dumb to remember for sure


I use mine for milling and for the bigguns, you decide how it works with 404, 50", 8 tooth .........

 

[huskihl]

If you already have the black coil, I believe you will not have to advance the flywheel.

I have to double check, I'm smart enough to know that I'm too dumb to remember for sure


I use mine for milling and for the bigguns, you decide how it works with 404, 50", 8 tooth .........

Opposite. If you have the green coil, 272 coils are direct replacement

 

[Moparmyway]

If you already have the black coil, I believe you will not have to advance the flywheel.

I have to double check, I'm smart enough to know that I'm too dumb to remember for sure

I'll get it right sooner or later, I just don't remember ...............

Opposite. If you have the green coil, 272 coils are direct replacement

BAM !!!!
Thanks Kev !!!!!!!!!

 

[qurotro]

Opposite. If you have the green coil, 272 coils are direct replacement

Kevin is right. Black coil need work to the flywheel and green dont.

 

[huskyhank]

Adding an air screw to the carb is the big thing, then an unlimited coil and opening up the muffler. Those 3 things will show huge improvement. The air screw is needed when you up the rpm with the coil and move more exhaust out. You need more fuel in the mix. Porting would be the next step.

 

[Lakeyboy89]

I use mine for milling and for the bigguns, you decide how it works with 404, 50", 8 tooth .........

[/QUOTE]

Now that's how I expect a big saw to perform!

 

[Lakeyboy89]

Adding an air screw to the carb is the big thing, then an unlimited coil and opening up the muffler. Those 3 things will show huge improvement. The air screw is needed when you up the rpm with the coil and move more exhaust out. You need more fuel in the mix. Porting would be the next step.

I have some micro drills to open up the hi jet when I get there, I would really like to have a fully adjustable carb but being in the UK there isn't anyone I know of that can do the mod for me and I wouldn't trust my self to take that on

 

[jcf86mod]

I recently got possession of an XS3120, highly recommended to get ported if you can.
I'm running Oregan 27RX super skip, which was recommended to me for milling.
Running 72" bar

 

[Lakeyboy89]

I recently got possession of an XS3120, highly recommended to get ported if you can.
I'm running Oregan 27RX super skip, which was recommended to me for milling.
Running 72" barView attachment 334923 View attachment 334924

Nice man! Been using a 48" lo-pro bar for milling work just bought myself a nice new cannon bar and skip chain for cross cutting and felling work!

 

[Maintenance Chief]

I recently got possession of an XS3120, highly recommended to get ported if you can.
I'm running Oregan 27RX super skip, which was recommended to me for milling.
Running 72" barView attachment 334923 View attachment 334924

Super skip nice for sharpening I bet.

 

[kneedeepinsaws]

Super skip nice for sharpening I bet.

Lol can u imagine?
I get irritated with 27” full comp sharpening

 

[jcf86mod]

Super skip nice for sharpening I bet.

Yes, unfortunately a reality when it comes to big bars