066 carb tuning after muffler mod

Paddymelon · Aug 19, 2012

G'day everyone,

First off, please excuse my ignorance if I ask something stupid, I've been looking around here at all the great info but need to ask some questions.

I have a 066 that I've just got 2nd hand, in very good condition but I'd like to do a muffler mod to it. Might do the same to my MS381 too if I get excited.

My question is: When tuning the carb after the mod, I know the max revs for my model is 13000rpm. With the effects that the muffler modification is to have, should the high revs still be 13000 (with more torque?) or is the mod supposed to increase actual rpm? (like I said, excuse my ignorance).

Thanks in advance!

Russell

deye223 · Aug 19, 2012

tune to the same RPM it's what i would do. if it's ported thats another story all together. wellcome to AS

D

ps if it's an aus model it should have a duel port cover on it

GASoline71 · Aug 19, 2012

deye223 said:
ps if it's an aus model it should have a duel port cover on it

Also know as the "fightin' cover". :laugh:

Gary

deye223 · Aug 19, 2012

GASoline71 said:
Also know as the "fightin' cover".

Gary

47 years young and still can't spell :haha:

roostersgt · Aug 19, 2012

I set mine to the max rpm, minus 300-500 rpm's. I like to run mine a little rich to be safe, regardless of whether or not they are muffler modded. Can't go wrong setting to factory specs. I believe in addition to ensuring the saw won't be set too lean, the factory specs also ensure you won't be damaging the bearings.

Tzed250 · Aug 19, 2012

roostersgt said:
I set mine to the max rpm, minus 300-500 rpm's. I like to run mine a little rich to be safe, regardless of whether or not they are muffler modded. Can't go wrong setting to factory specs. I believe in addition to ensuring the saw won't be set too lean, the factory specs also ensure you won't be damaging the bearings.

It's actually the piston skirts you need to worry about.

roostersgt · Aug 20, 2012

TZED,

I believe we're both correct. Either one could be damaged by excessive rpm's. Good call.

Rod Bearing Failure on Pro Saws

Piston Failure Analysis

Paddymelon · Sep 1, 2012

Cheers!

Hi,

A big thanks to all that have helped with answers to my posts...took the 066 out for the first time today after new HD2 filter, muffler mods, re-tuned, 25" bar 3/8th s.chisel (x 3 chains), nice and sharp. This thing just chews, the bar was fully buried into the redgum and didn't even look like stopping. It does use a bit more fuel but it sure does get through it faster and easier! Inspected the spark after the first tank and it had a nice tan color, I've only tuned by ear according to some instructions I found here but will see what my revs say once my digital tacho arrives (warm up first of course).

Apart from getting my ute bogged to the arse (had a lot of rain so I should have been more careful), it was an enjoyable day. Will try to attach a pic here!

Cheers!

Russell

View attachment 250908 View attachment 250909

deye223 · Sep 1, 2012

fearofpavement · Sep 1, 2012

Where's the pics of the stuck truck?

ri chevy · Sep 1, 2012

Where's the photo of the saw?

Where's the saw? We want to see the saw!

:hmm3grin2orange:

deye223 · Sep 1, 2012

fearofpavement said:
Where's the pics of the stuck truck?

are you blind

Mad Professor · Sep 1, 2012

Paddymelon said:
Hi,

A big thanks to all that have helped with answers to my posts...took the 066 out for the first time today after new HD2 filter, muffler mods, re-tuned, 25" bar 3/8th s.chisel (x 3 chains), nice and sharp. This thing just chews, the bar was fully buried into the redgum and didn't even look like stopping. It does use a bit more fuel but it sure does get through it faster and easier! Inspected the spark after the first tank and it had a nice tan color, I've only tuned by ear according to some instructions I found here but will see what my revs say once my digital tacho arrives (warm up first of course).

Apart from getting my ute bogged to the arse (had a lot of rain so I should have been more careful), it was an enjoyable day. Will try to attach a pic here!

Cheers!

Russell

View attachment 250908 View attachment 250909

I have no tach so I also tune by ear in the full cut.

The HD filter is a good investment, if you stay on top of things and clean the cover and carb area regularly all you will need to clean is the outer"sock" that covers the filter itself. Takes quite a while before the filter itself needs work. A cheap paint brush works good for getting the dust out of carb area.

Concerning the stuck truck, Fur Fish Game had a good article this month about getting unstuck, written by a man who did it for the military.

fearofpavement · Sep 3, 2012

deye223 said:
are you blind

Not blind, just stupid. I didn't realize there were two photo links and only looked at the one. So today I found the stuck truck pic and now can rest easy...

MTNBOY · Oct 12, 2012

the mods

I tend to run my 660 on the slight rich side just cause i have it set in my mill. the muffler mod deffinantly helped my saw both in power and running cooler. Noticed approx 25 degrees cooler with the non contact thermometer from cheap freight. as for the current 066 with poly flywheel and bb kit im building thats gonna be run on the edge just to see what i can do with her. dual port would be an easy way to go and decent price on scare bay for one with alittle cage work after you get it.

066 carb tuning after muffler mod

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