My Tach Installation (Stihl MS-441 R C-M) -- Looks nice, but...bad idea?

[MtnMike]

Hello Gents,

Long time lurker; very first post. Nice to be here....and thanks for all the great advice and information you all impart!

I thought I'd share my tach installation and solicit some thoughts on the job.

First, the finished product:

Yes...this took HOURS! Why can't they make these things square?! But not bad looking, no? I think the tach is supposed to be KTM Orange but it's a pretty good match to Stihl Orange.

So, the question for you knowledgeable guys: The tach does stick down into the air filter space a bit...a good bit...a good 1/4". According to the fancy Stihl animations, air is forced up into this cavity to be sucked into the filter and engine. I have what amounts to a pink school eraser sticking into that air filter space. How will this affect the operation of the saw? The obvious answer is, "go out and run the saw, dummy, and find out for yourself." But I can't get out any time soon, and I'd like to get some thoughts on whether even running the saw in this condition is a good idea or not. (The tach does not touch the air filter element, so vibration won't rub a hole in it.)

(Nevermind whether this is good for the tach or not. Sitting in that incoming air stream may kill it, but if it does, I'm only out $35...and the cost of a new cowling without a tach-shaped hole in it.)

This is an M-Tronic saw, so I'm thinking (hoping!) the carb can "think it's way around" this obstruction, but I have no evidence one way or the other if it will. My plan is to "reboot" the carb when I do get a chance to try out the modification. (I've not seen anyone post the M-Tronic carb reset procedure here yet, so if anyone thinks that would be useful, let me know and I'll post it.)

(And, yes, this is a new'ish saw [just 15h], so it will get an OEM cowling if and when it does go in for warranty repair.)

So...am I headed for trouble?

Thanks!

-Mike

 

[fuzz1500]

I have no idea...but thats a fricken cool set-up !!!

 

[Stihlman441]

If that tach is the same as the Works Connectoin(looks the same) tachs then it wont work right on the MTronics,been there done that.

 

[MtnMike]

Fuzz1500: Thanks! But your praise my be unwarranted with what Sithlman says. Grrrrrr.

Stihlman441: Whoa, won't work on the M-Tronics?! Tell me more. What happens (or doesn't happen)? Are RPMs off? Chronometer doesn't count up? Whole thing has a wobbler?

I haven't actually run up the saw with the tach installed yet. Seems like the first thing I'd have done, but long story why I haven't. Right now the tach is actually hooked up to my Jeep. I'm trying to put 15h on the clock before I hook it to the saw.

This isn't a Works Connection branded tach, it's branded "TTO", but I'll bet they're the same and from the same manufacturer. "Badge engineering" at it's finest.

I'm gonna be a bit irked...and feel pretty dumb if this doesn't work.

-Mike

 

[Stihlman441]

I did a thread on it but cant find it in the new forum system.
If i recall the higher rpms dont read correctly,they go all spastic and the hrs didnt seem to be accurate.
I have these tachs on allmost all my saws except the MTronics.
Sorry

 

[MtnMike]

Well, crud.

Guess I'll be tromping out into the snow tomorrow to see what mine does. It's accumulating time and registering accurate RPMs in the Jeep, so the unit itself seems okay. Now to see what affect the M-Tronic has on it. Probably the same thing you saw.

I wonder what kind of RF or EMI that M-Tronic system is pumping out to make the tach go bonkers. Maybe if I put a ferrite bead on the sensor lead. In the amateur radio biz, if anything's acting fishy, start by putting a ferrite bead on something. Haha.

M-Tronic doesn't affect the spark pulse, does it? I thought it just fiddled with the carb.

Thanks Stihlman.

 

[MasterMech]

Well, crud.

Guess I'll be tromping out into the snow tomorrow to see what mine does. It's accumulating time and registering accurate RPMs in the Jeep, so the unit itself seems okay. Now to see what affect the M-Tronic has on it. Probably the same thing you saw.

I wonder what kind of RF or EMI that M-Tronic system is pumping out to make the tach go bonkers. Maybe if I put a ferrite bead on the sensor lead. In the amateur radio biz, if anything's acting fishy, start by putting a ferrite bead on something. Haha.

M-Tronic doesn't affect the spark pulse, does it? I thought it just fiddled with the carb.

Thanks Stihlman.

M-tronic machines also monkey with the ignition timing differently than a standard 441 coil IIRC.

As the newish (and thrilled) owner of two m-tronic machines, 441/261, I'm very interested in this thread. And frickin' love that tach installed in the cover!

 

[Stihlman441]

The thing is but on the MTronics the hr meter is the only advantage having the tach on there.
Easyer way is the count the tanks of fuel which works about 30 mins run time / tank.

 

[JakeG]

Nice install! I've never seen a tach frenched in like that. They're usually strapped to the handle!

 

[DexterDay]

Awesome job installing the Tach! Looks like an OEM installed part!

Hoping it works out for ya Because now I want one on mine

 

[zogger]

That is quite a nice mod. Even if it doesn't work on the mtronic, there's a million other saws out there that could work with that, think, new biz for you!

We have pro engine modders, bar and bar adapter modders, muffler modders, and we need chassis modders!

Tell ya another one saws should have, a temp sensor.

 

[blsnelling]

As awesome as your installation is, Stihlman441 is correct. I've yet to see a MTronic saw work on a tach.

 

[old-cat]

Pick a saw it will work on and market it!

 

[naturelover]

I was thinking they worked under load maybe? I thought I remembered someone here had one strapped to a 441c...,


Sent from my iPhone 5 using Tapatalk

 

[mesupra]

Looks factory, I sure hope it works, way better than my zipped tied $12 tach from Amazon, the color would would even work with the superior brand lol I look forward to seeing if it works, does anyone know if the auto tune coil has issues with tachs

 

[MtnMike]

Gents,

Thanks for the positive words, and glad at least the verdict on the aesthetics is favorable.

The observations and experiences of Brad and Stihlman are a bit discouraging. Based on their findings, being in agreement with each other that this tach doesn't work on M-Tronics, I doubt my experience will be any different. Apologies that I can't yet post my results...still can't get out of my dang office! Doubt it'll be any different that what has already been said...

I'm hoping, however, that at least the chronometer function will work--notwithstanding Stihlman's experiences. I'm equally interested in how many hours I have on my saw as I am in my RPMs. So if this part at least works, I'll deem this a success.

So...if at least the chrono function works, and I leave this in my saw, anybody got any thoughts on my original question: Will it impede the airflow sufficiently to degrade the saw's performance or longevity?

I have thought about trying to offer this as a service--I'd pay someone to do it! But it is spectacularly time consuming, and really easy to screw up! And the same reason I'm not a doctor would prevent me from considering doing this for other people: I make waaaay too many mistakes! I've reached out to a few CNC shops, and have started working on a CAD drawing. If I can get those two things to come together, and guarantee a precise, error-free fit every time, I would be more than happy to put this out as a service to you guys. That wasn't my original intention. I was just kinda proud of my accomplishment and thought you guys might appreciate this and want to try it out for yourself. Mainly, I just didn't want to bust my tach off my handlebar! Maybe I just make a template kit out of a mildly-malleable metal that you can conform to your saw cowling , and then you cut it in yourself. Getting the shape and size correct is the hardest part.

Once again, thanks everyone for your comments and thoughts. As soon as I get a field trial, I'll post the results.

 

[zogger]

I see that same company, TTO, has one that is tach, hours *and* temperature.

 

[Stihlman441]

Sorry Mike for being the one with the bad news,all may not be lost yet you will just have to try it.
Besides that its a great idear and you did a brilliant job of it.

 

[wyk]

So sell it to someone with a standard 441?

 

[trophyhunter]

That's the best looking saw mod I've ever seen, nice work!