It's here! The M-Tronic MS261C is finally here.

[lly_duramax]

Brad,
IIRC you put an 044 carb on the 1st 261 you built at the end of the thread and it looked super strong. I'm thinking if the m-tronic can fuel it like an 044 carb it will beat the snot out of a ported 261 with the stock carb.

 

[blsnelling]

I only replaced that carb because I ruined the original trying to mod it. How much that added I'm not sure. What I do know, is that they run super strong with the stock carb. Swapping carbs is not a service I offer, so is really a moot point. Unless the venturi is larger, i don't see how the carb alone can make it make more power.

 

[blsnelling]

Just for the record, I'm not expecting this saw to make more power than the original version after porting. In stock form, maybe. Mods seem to level the playing field with the 441s, although I have not compared them back to back. An engine is an air pump. The engines are the same. The difference I'd in the state of tune. That is all optimized as part of the porting process. For example, timing advance alone is worth significant gains on many, not all, saws. MTronic does that for us, real time.

 

[Highdesignfool]

If plans fall through with the stock 261 to compare with,
I'll take up your offer to muffler mod mine. It's brand new with only a few tanks through it. I can send it off on a hurry.

 

[SAWMIKAZE]

Fortunately, a new regular MS261 is supposed to be heading my way tomorrow. All of my testing will be in the same cant, so will have a real good idea. All testing won't be on the same day, but, will be in the same wood, with the same B&C.

Its on its way brad..be easy on her shes brand new

 

[LowVolt]

Its on its way brad..be easy on her shes brand new

I am VERY peticular about my saws. Don't worry it is in good hands.

 

[blsnelling]

I am VERY peticular about my saws. Don't worry it is in good hands.

Yours has been run and is cleaned back up. I didn't think about it until later, but I used your chain, which means I'll have to keep that chain until I'm done with this. I'll be done within the next few days though.

Videos coming.

1. MS261C - Stock
2. MS261C - Muffler Modded
3. MS261 - Ported

Tomorrow/Saturday, I'll be cutting the cylinder base, and retesting. I'll then advance the ignition and retest. After that, it's time to port it. The new regular MS261 is on it's way, so will be getting the vids of it stock, MMd, and timing advanced.

I'm just beginning the editing process, so it'll be a while.

 

[SAWMIKAZE]

Ive always wanted a ported 261..ive been waiting for quite a while..the suspense of these results is killin me already. :msp_thumbsup:

 

[LowVolt]

Ive always wanted a ported 261..ive been waiting for quite a while..the suspense of these results is killin me already. :msp_thumbsup:

As it should be.

What size bar and chain are you running? 3/8" or .325?

 

[blsnelling]

Stock MS261C. 18" B&C. Stihl RSC .325 chain. 7-pin rim.

[video=youtube_share;oKnLPcgZKls]http://youtu.be/oKnLPcgZKls[/video]

 

[blsnelling]

Modding the muffler made a huge difference. Throttle response and power both improved significantly. BTW, I've not yet timed any of these.

[video=youtube_share;GhKPGl0givE]http://youtu.be/GhKPGl0givE[/video]

 

[SAWMIKAZE]

As it should be.

What size bar and chain are you running? 3/8" or .325?

Ill be runnin 16 and 18 .325...ill be swappin between 7 and 8 pins to see whats what.

 

[blsnelling]

Here's LowVolt's ported and fully modded regular MS261. This is with the same sprocket, bar, chain, and fuel.

[video=youtube_share;Y46JBs2r4T0]http://youtu.be/Y46JBs2r4T0[/video]

 

[Slackerjpt]

I find this to be very exciting stuff. Do I have CAD?

opcorn:

 

[Philbert]

So the muffler modded only CM appeared to be a bit slower than the fully modded 261. Does the CM model have to 'learn' (adjust) to the new conditions?

Philbert

 

[LowVolt]

Here are the times that I recorded using my dumb phone's stopwatch.

Stock MS261CM:

3.84
3.91
4.55
4.68
4.56

MM MS261CM:

2.94
2.94
2.87
3.00
2.73
2.92

Ported MS261 (Rich):

2.50
2.17
2.17
1.99
2.09
2.11

Ported MS261 (Lean):

2.04
1.98
2.11
1.91
1.92
1.85

 

[blsnelling]

I didn't notice the knot when cutting with the stock saw until it was too late. Regardless, the muffler mod made a WORLD of difference. With the numbers we have, it's like a 32% gain!

 

[LowVolt]

Here's LowVolt's ported and fully modded regular MS261. This is with the same sprocket, bar, chain, and fuel.

Did you swap out my sprocket brad? I was running an 8 pin.

 

[blsnelling]

Looks like Rory's saw is about 32% faster than the MMd 261C.

Look at the difference re-tuning made. That's why it's so important to have a saw tuned right when making comparisons. In this case, it made for a 6-7% improvement.

 

[blsnelling]

Did you swap out my sprocket brad? I was running an 8 pin.

I did, just to keep everything even. I'll be running a 7-pin for all 261 cuts. When I'm done with the 261C, and if I have enough wood, I'll try to test 7-pin vs 8-pin.