660 same wood w/ 20 24 28 32 36" also 461

[redbull660]

22-23" piece of oak, new stihl RS chains for each bar length, full oiler, cleaned filter & topped off gas/oil after each run, double checked tension, saw warm before I started testing,

Tune - just had to richen H some with the 20" and lean a hair as I went up in bar length to maintain 13,300 according to the fast tach.

28-36" and above seemed the smoothest. 28" probably the best feel.

20" Tsumura & new RS Chain - 17.6 , 18.6
24" Tsumura & new RS Chain - 16.4, 17.0
28" Tsumura & new RS chain - 15.8 15.9
32" Tsumura & new RS chain - 17.6 17.2 - thinking a little rich here tach'd at 13k (figured it was fine, was in running out of daylight)
36" Tsumura & new RS chain - 16.6 15.8 faster than the 20" ???!? wtf. (plus I cut the piece smaller for the 20" cuts...must have been cuz nose buried?) I don't think the wood changed. Maybe the longer bars keep the chain cooler?

 

[mdavlee]

Nice tests.

 

[redbull660]

note: I did check the log this morning and it shrunk from 23" across to 22" So might explain why the 461 was as fast as the 660. In any case amazing they are so close, and amazing the long bars did so well vs shorter.


461 - not sure what to think on the 461... Did everything the same as the 660. Only thing that would be different is how I tune it. Even with the H turned out to max rich, the saw will still go right to the 13.5k limit. Which screws up the Fast Tach. So i just leave it max rich all the time figuring if I pulled the caps I could go even richer and still hit the limiter 13.5. Guess I'm not sure how I should tune this damn thing.

Note both the 660 and 461 have triple ported muffler setups. Seems to work awesome in the 461.

Anyway - 461 times are faster. But it's later in the log and the temp dropped. But still that shouldn't matter that much? However, I must say every little mini test I've done between the 461 and 660, where the cuts were back to back, the 660 won. Not by much, usually a second.

Here are the 461 times

20 tsumura & new rs chain - 17.1 17.1 rough in cut
24 tsumura & new rs chain - 17.3 18.1 rough in cut
28 tsumura & new rs chain - 15.6 15.5 SMOOTH
32 tsumura & new RS chain - 15.5 15.4 ??!??
36 tsumura & new rs chain - 16.5 15.5 ?!!??

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36 - loading yet...

 

[big t double]

Neat-o

 

[Trx250r180]

your tach will maybe read better if put an ms460 coil on the 461 ,my 461 was bouncing off the rev limiter all the time till i did the change on mine

 

[mdavlee]

You'll have to play with it in a log tuning and making a cut and timing it. That's how I do the 7900. Just video it and each time I change the tune to get the best cut speed and sound in the wood. I'm beginning to really not like limited coils. I swapped the one from the 372 and it was hitting 14.5k with just a coil change.

 

[SawTroll]

Maybe your tuning suited the longer bars better - like the setting was a bit rich with the shorter bars?

 

[SawTroll]

Also, maybe the saw was warmed up better as you worked through the testing?

 

[redbull660]

as stated in first post, saws were warmed up. (I cut with both of them probably 15-20min, prior to starting the testing. )

 

[SawTroll]

I could see that on the 461. But not the 660...I was at 13,200-13,300 for all the tunes except the 32 which was like 13000-13100. or am i missing something?

You are "missing" the fact that you leaned the carb as the bars got longer, to maintain the rpm.

 

[Trx250r180]

Like mike said tune in the wood with the bar you are going to use ,i never use a tach ,i just drop the saw into a log and adjust till it pulls the hardest ,13500 may not be the happy spot for one but may be for the other for example


also think of that 660 like a truck diesel engine ,the more it is loaded the happier it will perform ,that is why you do not get fast results with a 20 inch bar for that saw ,it was not made to run a small bar ,mine does not shine over the 75 cc saws till you get in 36 inch bar territory ,32 they are real close ,28 it loses

 

[SawTroll]

Never really thought of it - but tuning for best performance with each bar length, instead of a set WOT rpm out of wood rpm, seems right?

 

[mdavlee]

Tune for performance and reference with a tach for later.

 

[redoakneck]

nice work. A 20" bar and out of the box chain isn't going to load a 660 nearly enough, kinda like snow tires on a dragster.

 

[SawTroll]

nice work. A 20" bar and out of the box chain isn't going to load a 660 nearly enough, kinda like snow tires on a dragster.

Larger drive sprockets really should be tested with the shorter bars - which of course would expend the project even more.....

 

[redbull660]

already in my plans to do just that. lol

 

[Ron660]

22-23" piece of oak, new stihl RS chains for each bar length, full oiler, cleaned filter & topped off gas/oil after each run, double checked tension, saw warm before I started testing,

Tune - just had to richen H some with the 20" and lean a hair as I went up in bar length to maintain 13,300 according to the fast tach.

28-36" and above seemed the smoothest. 28" probably the best feel.

20" Tsumura & new RS Chain - 17.6 , 18.6
24" Tsumura & new RS Chain - 16.4, 17.0
28" Tsumura & new RS chain - 15.8 15.9
32" Tsumura & new RS chain - 17.6 17.2 - thinking a little rich here tach'd at 13k (figured it was fine, was in running out of daylight)
36" Tsumura & new RS chain - 16.6 15.8 faster than the 20" ???!? wtf. (plus I cut the piece smaller for the 20" cuts...must have been cuz nose buried?) I don't think the wood changed. Maybe the longer bars keep the chain cooler?

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24


28


32


36

I like my 28" on my 660.

 

[spindrift7mm]

Welcome to the West Coast Long Bar World ! Great test kinda real world.

 

[wyk]

36" Tsumura & new RS chain - 16.6 15.8 faster than the 20" ???!? wtf. (plus I cut the piece smaller for the 20" cuts...must have been cuz nose buried?) I don't think the wood changed. Maybe the longer bars keep the chain cooler?

That 20" bar is buried in wood. I modify the tail of my teeth so the bar cuts smoothly when buried in wood. This is why:

Not as much drag on a standard tip, but I notice a difference when bore cutting.

 

[Ron660]

461 - not sure what to think on the 461... Did everything the same as the 660. Only thing that would be different is how I tune it. Even with the H turned out to max rich, the saw will still go right to the 13.5k limit. Which screws up the Fast Tach. So i just leave it max rich all the time figuring if I pulled the caps I could go even richer and still hit the limiter 13.5. Guess I'm not sure how I should tune this damn thing.

Note both the 660 and 461 have triple ported muffler setups. Seems to work awesome in the 461.

Anyway - 461 times are faster. But it's later in the log and the temp dropped. But still that shouldn't matter that much? However, I must say every little mini test I've done between the 461 and 660, where the cuts were back to back, the 660 won. Not by much, usually a second.

Here are the 461 times

20 tsumura & new rs chain - 17.1 17.1 rough in cut
24 tsumura & new rs chain - 17.3 18.1 rough in cut
28 tsumura & new rs chain - 15.6 15.5 SMOOTH
32 tsumura & new RS chain - 15.5 15.4 ??!??
36 tsumura & new rs chain - 16.5 15.5 ?!!??

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24


28


32



I'd like to see the test repeated with both saws ported.

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