3120 Spice Up thread

[Brewz]

Hi folks

I have met a local bloke who is a tree lopper with dozens of saws that he wants me to service for him in the new year as he is over using the local shops that cost a lot and do a bad job.

He rang me this arvo telling me he has a 3120 that is a 1998 model but like new, having done bugger all work.
He wants me to port it and make it go better for him. He want to be able to hear it and know he is holding onto it.
I sent him a video of my ported 084 and he said Yep, like that!

My main limitation is that I will not be able to lower the cylinder as I don't have a lathe, so I am planning a simple gasket delete and some porting matched with a good muffler mod.

My big questions are:

Will the carb on this older saw need modifying? If yes I would love to know how to do it.
I have read of a couple different coils on these saws. Which one is the best and how do I tell the difference?
Some pictures of good muffler mods for inspiration would be good

Hell, any pictures, tips, tricks, thoughts, ideas, port timings and info on what has worked in the past would be fantastic. I did a bit of searching and couldn't find a good 3120 info archive so lets build one.

 

[Iron.and.bark]

While a tuneable carb is highly desired. Find out what fixed jet size it has. If it has the 1.25 in there from personal experience it will support this

Grill in muffler outlet removed, 4 holes drilled around pipe within muffler (lots of improvement and keeps sound reasonable), exhaust port widened. Intake is pushing a fixed jet a little to much. Even with these two mods I mentioned saw is night and day diff.

Could also ream out fixed jet aswell. If anything a fixed jet may be a good idea for a tree service...

 

[Brewz]

I always thought fixed jet carbs fed more fuel which kept RPM's lower
Wouldn't boring it out limit it more?

 

[Brewz]

Ahhh The carbs have no adjustment at all?
Ahhhhhhhhhh

So porting will introduce more air and lean the saw out so you need to open up the jet to get enough fuel back in?

 

[Iron.and.bark]

Zactly.

If my case with a 1.25 jet basically killed the top end power. Mods made it leaner and gave the plug that nice chocolate brown colour.

Only l was adjustable

 

[Brewz]

Are all 3120 carbs locked down on the H?

 

[Iron.and.bark]

The original ones had primer bulbs and could be tuned. Anything afterwards is fixed as far as I know.

Ment to send mine to mastermind to add an adjustable h too, but been lazy...

 

[Brewz]

Just spoke to him.
No primer bulb
I should have it soon. Let the fun begin!

 

[Brewz]

but been lazy...

Sitting next to that 08S throttle trigger?

 

[Adirondackstihl]

 

[CR888]

Randy mods 3120 carbs nice making them adjustable. He's done a bunch and does a good job.

 

[Brewz]

Randy mods 3120 carbs nice making them adjustable. He's done a bunch and does a good job.

Thanks mate
If I find it needs it I will have to speak to him

 

[Adirondackstihl]

Thanks mate
If I find it needs it I will have to speak to him

I'd probably go that route anyway

 

[SixGun]

3120 Dual port muff, coil from husky 61, drilled main jet to 1.21mm

 

[SixGun]

Timing was dead on with advance of stock coil and ended up finishing the fixed jet with a torch tip cleaner that was 1.21 mm.
This combo with no porting made a very good running saw.
I think it was running between 11500 and 12000

 

[Brewz]

The original ones had primer bulbs and could be tuned. Anything afterwards is fixed as far as I know.

I just spoke with the owner and he is bring it along with a heap of other saws around on Sunday.
He has told me that after a better look, the 3120 does in fact have the primer bulb

Now I'm excited

 

[Crzybowhntr]

 

[Mastermind]

Glad to help out of you need it. The alerts ain't working real well now though. You might have to message me to get my attention.

 

[Brewz]

Should be right thanks mate.
I don't have a lathe so wont be able to go further than a gasket delete.
Will widen the exhaust a bit, touch up the intake a bit, a bit of directional work in the transfers, muffler mod, timing advance and see how it goes.

I just love big saws!

 

[Mastermind]

When you look at that carb, you'll be disappointed. Only the WG3 has an adjustable high side.