stihl 066 porting

[Keith Gandy]

I bought my bar and chain off redbull661. He told me whatever I have was .050.

It was grabby, to say the least.

Yeah, my MM066 is ballsy.

Heck ya !! It better be ballsy at .050 . Alota raker to pull too. Does it pull hard? Gotta hold it off the dogs?

 

[drf256]

Now I need to measure it.

Yes, it pulls the dogs in.

 

[Dieselshawn]

Hello fellas, I'm wondering if different places mean different tunes?

My mastermind 066 came from missori up to Canada to me.

When I first got it, I checked with the tach and it was running 13,200 rpms. So I left it alone as that's what mastermind wants.

After a while, it became obvious the saw is running really rich. Spark plug is black and exhaust port is really wet.

Also I wasn't winning dyno competitions against other 660's tuned to 14-15,000. For 1-2 seconds my saw would produce the highest number by far on the machine then fall flat on its face under heavy load from the dyno.

So I had a guy tune the saw to 14,100 which is the best and fastest tune in the wood with a 36" bar.

The dyno now reads high amounts of torque.

Just last night at the last minute ported big cube saw gtg, my mastermind saw won.

The exhaust opening on one side is large enough to stick a finger in, so I can clearly see the piston and exhaust port.

It's still shiny and wet looking.

I'm liking that Yamaha 2R oil as well....

 

[Mastermind]

I think fuel plays a huge role in tune.

 

[huskihl]

Hello fellas, I'm wondering if different places mean different tunes?

My mastermind 066 came from missori up to Canada to me.

When I first got it, I checked with the tach and it was running 13,200 rpms. So I left it alone as that's what mastermind wants.

After a while, it became obvious the saw is running really rich. Spark plug is black and exhaust port is really wet.

Also I wasn't winning dyno competitions against other 660's tuned to 14-15,000. For 1-2 seconds my saw would produce the highest number by far on the machine then fall flat on its face under heavy load from the dyno.

So I had a guy tune the saw to 14,100 which is the best and fastest tune in the wood with a 36" bar.

The dyno now reads high amounts of torque.

Just last night at the last minute ported big cube saw gtg, my mastermind saw won.

The exhaust opening on one side is large enough to stick a finger in, so I can clearly see the piston and exhaust port.

It's still shiny and wet looking.

I'm liking that Yamaha 2R oil as well....

At $4 a gallon in canucky, I'd be leaning that beotch out too lol

 

[Definitive Dave]

fuel
oil
oil mix
atmospheric pressure
temperature
humidity
air filter condition
probably even what the operator had for dinner Everything matters
Dave

 

[jmssaws]

Tune changes constantly, anything can change it. I fund a 66 is strongest around 14200 give or take a few hundred. The way I port one anyway, I usually have the exhaust over 100 though.

 

[Moparmyway]

I think off the roll is .030?

.050 is low takes a good saw to noodle with that

I have measured both new RS and new RSL in .404 ......... Got anything from .030 to .050 and everything in between, same roll in each too

 

[Keith Gandy]

I have measured both new RS and new RSL in .404 ......... Got anything from .030 to .050 and everything in between, same roll in each too

I measured brandnew rslf yesterday with a straight edge and feeler gauges. .018

 

[Moparmyway]

I measured brandnew rslf yesterday with a straight edge and feeler gauges. .018

I use calipers on a .100 shim
EasyPeasy

 

[Keith Gandy]

View attachment 13437
I use calipers on a .100 shim
EasyPeasy

Ya I just measured rs 404 and got .026 to .028

 

[Keith Gandy]

Wonder why the round rakers r so much higher than square rakers?

 

[Deets066]

Tune changes constantly, anything can change it. I fund a 66 is strongest around 14200 give or take a few hundred. The way I port one anyway, I usually have the exhaust over 100 though.

Two badass 66's both were tuned at 14,100-14,200

 

[stihl_head1982]

Two badass 66's both were tuned at 14,100-14,200

LOVE-LEE!
Very impressive. Are you holding it off the dogs so it can progress faster thru the cut? (forgive my ignorance, I am learning). Did you do these two saws or was it another porter?

 

[jmssaws]

I ported the first one and deets ported the second. Both are strong

 

[stihl_head1982]

How many steps are you taking to increase performance.
Cut base, squish, change port timing, file the flywheel key, mod the muffler...? Or is this asking for too much in a nutshell?

 

[jmssaws]

How many steps are you taking to increase performance.
Cut base, squish, change port timing, file the flywheel key, mod the muffler...? Or is this asking for too much in a nutshell?

All of that,what do you want to know?
I keep notes secrets,I'll share with anyone who's interested.

 

[Canadian farm boy]

@jmssaws My big question is how do you know how much you need to cut from the squish and base? Is this just something that comes with experience on a certain model or is there a science behind it?

 

[Red97]

All of that,what do you want to know?
I keep notes secrets,I'll share with anyone who's interested.

Pics of the muffler mod?

 

[Red97]

@jmssaws My big question is how do you know how much you need to cut from the squish and base? Is this just something that comes with experience on a certain model or is there a science behind it?

Where you want the intake to land.