Testing different timing advances on tree monkeyed 661

[Redbull661]

Friend of mine @Tbrown milled up some timing keys for me with various amounts taken off.

Tested

.0755 (stock)
.0650
.0550 (.02 off ...what I most often hear)
.0500
.0450
.0375

The setup: Tree monkey 661 36" cannon bar. 6 new stihl .404 RS full comp chains. wood is oak ties banded together approx 29 x 36"


Tools

new chains taken off the roll in order.

keys - perfectly milled... so .0550 is .0550 exactly!

pic of results attached.

 

[mdavlee]

450 sounded crisp to me.

 

[Chainsaw Jim]

Thank you for taking the time to do this and sharing it with us.

 

[Backtroller]

Cool display. I always wanted to see what various amounts off would do. The temperatures were interesting.

 

[Gunn]

So based the times if we figure some sort of margin of error to account for knots and different variables from cut to cut, one might say they are really So close that there's barely any difference if any.

 

[Definitive Dave]

gotta love a real scientific test!!!
bravo and huzzah!!

 

[pro94lt]

Sure beats grinding a little slapping her back together and hoping for gains...

 

[Mastermind]

Redbull's tests have taught me a lot.

Big rep for you sir.

 

[junkman]

Does the m-tronic readjust for timing as well as the fuel ?
the last one seemed peppier at first then the times went back to the above ones on the second cut .

 

[Mastermind]

Does the m-tronic readjust for timing as well as the fuel ?
the last one seemed peppier at first then the times went back to the above ones on the second cut .

I don't think it does at all Brian. I believe it has a start mode (retarded) an idle mode, and an advance mode.

 

[Stihl working Hard]

Awesome thread @Redbull661 iam learning all the time thanks for putting this thread together

 

[Stihl working Hard]

Would be curious if there were any gains on a manual carb and euro coil on the 661

 

[junkman]

Redbull's tests have taught me a lot.

Big rep for you sir.

Whut he said times 2
Green rep for you for these tests

You guys make sure to buy the test chains when he puts up for sale ,He has a great price on oem stihl chains ,and real fair shipping prices also .

 

[Backtroller]

It would be nice to try this with other saws. Too bad it's such a large undertaking and very time consuming.

 

[junkman]

It would be nice to try this with other saws. Too bad it's such a large undertaking and very time consuming.

On my reg carb saws i only notice the difference when limbing,throttle response is quicker ,felling and bucking it may be different ,but i do not notice it as much .

 

[Redbull661]

It would be nice to try this with other saws. Too bad it's such a large undertaking and very time consuming.

I thought I could do 3 changes per hour...so about 2hrs. It took me 5hrs. Still don't understand how it took so long. I didn't even get side tracked talking to Scott!

process
- warm up saw in "burn" log with warm up chain.
- knock out filter
- new chain
- start saw and run full throttle to stretch chain
- re-tension chain
- get thermo started up
- top off with gas and oil
- do test cuts
- quickly take jug temp
- take off air filter cover and put on hard wired tach
- piss rev saw like heck ot get max no load reading
- write down your readings
change:
- take off cover and flywheel - you have to let key cool down or it deforms too easy punching it out
- while key is cooling down top off fuel + oil and pick up square cookies.
- measure and double check key - diamond file any mini burrs
- install key, flywheel etc.
- start saw and let it idle for 30 sec or so
- go do 5-6 cuts in "burn" log
-repeat.

So based the times if we figure some sort of margin of error to account for knots and different variables from cut to cut, one might say they are really So close that there's barely any difference if any.

Jug temps - I've heard people say that jug temp rises with more and more advance. I thought it was interesting that they all operated inside of 5 degrees difference

Max no load RPM - I think it's interesting how rpm started lower with stock key and rose til .045 and then we lost back to stock levels with the .0375 key. Pattern/trend is there.

Times dropped a little bit with each increase in advance up until .045 Then we lost again at .0375.

Differences in cut 1 to cut 2 - up until .045 the difference was minimal. both .045 and .0375 have a wider gap.

For me at least me personally - I am looking at all the data points and I am thinking ok I should redo 3 of these... start out with .0375 then go to .0450 and then depending on those results (do I repeat my earlier results? something new happen?) go to .0425 or .0475.
-----------------------------------------------------

and here is the real kicker!... So I am looking at all the data and saying most likely the best is between probably .0400 to .0450. Now the key that @tree monkey did which I removed for the test...he did it on a grinder by hand...just eye balling it...saying "yeah that looks good." .04350 LOL Which is probably perfect given the results.

Not only that, but I checked the other key in the other tree monkey 661 and it was .04380. Sooo that means he eye balled two them at different times by hand on a grinder to within .0030!!!

 

[stihl saws]

Awesome info, as always. Thanks for your efforts!

 

[stihl saws]

Whut he said times 2
Green rep for you for these tests

You guys make sure to buy the test chains when he puts up for sale ,He has a great price on oem stihl chains ,and real fair shipping prices also .

Yes he does. Great guy to deal with.

 

[Rains]

I Always enjoy your tests !! Thanks for all your hard work.

 

[jmssaws]

I thought I could do 3 changes per hour...so about 2hrs. It took me 5hrs. Still don't understand how it took so long. I didn't even get side tracked talking to Scott!

process
- warm up saw in "burn" log with warm up chain.
- knock out filter
- new chain
- start saw and run full throttle to stretch chain
- re-tension chain
- get thermo started up
- top off with gas and oil
- do test cuts
- quickly take jug temp
- take off air filter cover and put on hard wired tach
- piss rev saw like heck ot get max no load reading
- write down your readings
change:
- take off cover and flywheel - you have to let key cool down or it deforms too easy punching it out
- while key is cooling down top off fuel + oil and pick up square cookies.
- measure and double check key - diamond file any mini burrs
- install key, flywheel etc.
- start saw and let it idle for 30 sec or so
- go do 5-6 cuts in "burn" log
-repeat.



Jug temps - I've heard people say that jug temp rises with more and more advance. I thought it was interesting that they all operated inside of 5 degrees difference

Max no load RPM - I think it's interesting how rpm started lower with stock key and rose til .045 and then we lost back to stock levels with the .0375 key. Pattern/trend is there.

Times dropped a little bit with each increase in advance up until .045 Then we lost again at .0375.

Differences in cut 1 to cut 2 - up until .045 the difference was minimal. both .045 and .0375 have a wider gap.

For me at least me personally - I am looking at all the data points and I am thinking ok I should redo 3 of these... start out with .0375 then go to .0450 and then depending on those results (do I repeat my earlier results? something new happen?) go to .0425 or .0475.
-----------------------------------------------------

and here is the real kicker!... So I am looking at all the data and saying most likely the best is between probably .0400 to .0450. Now the key that @tree monkey did which I removed for the test...he did it on a grinder by hand...just eye balling it...saying "yeah that looks good." .04350 LOL Which is probably perfect given the results.

Not only that, but I checked the other key in the other tree monkey 661 and it was .04380. Sooo that means he eye balled two them at different times by hand on a grinder to within .0030!!!

You do this long enough you get a good eye for guessing thousands.
I've not done this as long as him but I and I'm sure he can cut 030 by hand out of a chamber and damn neer hit it dead without measuring,I do it all the time.

File a couple hundred keys and you know how much just by looking.