3120 Spice Up thread

[Brewz]

Will see what it is when its on the bench

 

[Postrip]

Brewz, the primer carb which is in fact a WG2, started in the 1st production of the 3120, it was phased out in 1989 when the WG6 took over with a choke shaft.

The WG2 never had an adjustable H needle, but does have an easily removed H jet(new jets are nla 4 that carb)
The WG2 has a larger Venturi than the WG6/8/10
3120's actually over fuel from new, so the gasket delete,light porting,muffler mod,ign advance will give him a beast 2 use.
Oh and a 272xp coil is the 1 to use, timing has to be advanced quite a bit with the original flywheel to make it run.
I've modified quite a few 3120's, to different specs & stages, the WG3 will NOT bolt straight on without being modified!
It's better to have an adjustable H needle put into the original carb.
I have many spares 4 the 371/2 395/3120
Maybe I should consider an informative 3120 build thread in the near future also

 

[Mastermind]

Like Jason said, to use the 272 coil on the saw with the WG2. the timing has to be advanced a great deal.

I can rebroach the flywheel so that it has the keyway in the correct place......but with you in OZ shipping is a killer. Glad to do it for you........just pay shipping if you want.

 

[Brewz]

Fantastic info
I will discuss all this with the owner when I see him.
What is the 3120 coil limited to?

I believe someone mentioned using a husky 61 coil as well as it has the correct timing.

I don't think he wants a hotrod, just wants the saw to run like a big saw should.

 

[Mastermind]

Fantastic info
I will discuss all this with the owner when I see him.
What is the 3120 coil limited to?

I believe someone mentioned using a husky 61 coil as well as it has the correct timing.

I don't think he wants a hotrod, just wants the saw to run like a big saw should.

The 61 coil will be timed the same as the 272 coil. That works on the newer 3120XPs with the green coil. But not on the older ones.

I'm not sure where the RPM limit is Tony.

 

[Brewz]

Roger that!

 

[Iron.and.bark]

Rpm limit is around 12.5k give or take a little at least on my one.

 

[Postrip]

The standard 3 legged coil is 9,600 from memory, 272 coil is unlimited.

 

[Postrip]

I never tune saws by tachometer!
I tune by ear, and in the wood, also keep an eye on plug colour .

 

[mdavlee]

Black coils is 12.5k. That's what mine is before the tach goes haywire

 

[Iron.and.bark]

Plug colour is always worth a check. Really the only way to guage if the fixed jet is running to rich.

 

[Nitroman]

I have a 3120 The Mastermind massaged. With the adjustable carb. This machine is truly a beast to behold.

You'll be really happy with the results you get.

 

[Brewz]

I stripped her down today. Its done NOTHING work wise.
hit it with a bit of degreaser and hosed it all off and its like new.

The muffler was loose when the owner bought the saw and apparently it came loose again after 5 minutes use and its done nothing since.
Quite a bit of damage to the back of the muffler and the cylinder but a file will fix that up just fine.





Carb appears to be a WG8 and does not have the primer bulb.
I have not opened it up yet byt will be ordering a set of micro drills tonight.



Also, the coil is black so 12500 it will be.
I don't think I will need it to run any faster. It wont be a race saw.

 

[Simondo]

I stripped her down today. Its done NOTHING work wise.
hit it with a bit of degreaser and hosed it all off and its like new.

The muffler was loose when the owner bought the saw and apparently it came loose again after 5 minutes use and its done nothing since.
Quite a bit of damage to the back of the muffler and the cylinder but a file will fix that up just fine.

View attachment 49509

View attachment 49510

Carb appears to be a WG8 and does not have the primer bulb.
I have not opened it up yet byt will be ordering a set of micro drills tonight.

View attachment 49511

Also, the coil is black so 12500 it will be.
I don't think I will need it to run any faster. It wont be a race saw.

Did it have the gasket behind the exhaust Brewz ?

 

[Brewz]

Went and drew some lines on the inside of the cylinder to mark where the piston runs and there is not much widening of anything going to be happening.
About all I will be doing is squaring out the base of the intake, belling out the exhaust tract and blending the bottom of the lowers a bit.







With gasket removed I get .013 squish so will take about .010 off the band.
Timing with gasket removed is 105/124/71.

Thinking I might give it just a touch more intake when I square it out and keep it a bit under square to keep the case pressure up
105/124/72 sounds good to me.

Muffler has already had the baffle removed completely. Saves me doing it.
Going to ditch the factory baffle all together and mod a large @Red97 baffle which will be longer and give me a much bigger open area to add a spark screen and stop hot gas melting the side of the hand guard
Speaking of deflectors, these are the last of the batch I bought. I may need to get some more



Gave up working on it.
Too hot in the garage.
I changed my weather thingy to F for the US folks
8:30pm

 

[Brewz]

Did it have the gasket behind the exhaust Brewz ?

No
Owner said it was loose when he got it so he tightened it down but it came loose very quickly so he stopped using it and its sat ever since.
I will be ordering a gasket.
The cylinder and muffler flanges have come up nice after a bit of a file

 

[Simondo]

No
Owner said it was loose when he got it so he tightened it down but it came loose very quickly so he stopped using it and its sat ever since.
I will be ordering a gasket.
The cylinder and muffler flanges have come up nice after a bit of a file

Having the proper compressible gasket has usually sorted out that issue with saws that have come to me without. I have tightened down.. then left the saw to cool and just a little bit of a final torque down (just like engine head bolts ).

 

[Iron.and.bark]

Pop the top off the carb and see what size fixed jet it has.

Wondering if the size of jet is reflected in carb model. Mine is a wg10 326 and has a 1.25mm

 

[Brewz]

1.12?

 

[Iron.and.bark]

1.12?

View attachment 49529

Be very careful, mine used this jet up with basically what you plan to do.