Stihl MS192T / MS193T mods, rebuilds, upgrades

[Stackowood]

The supply of good 192T saws is drying up so it's time to move on to the 193T to see if these strato saws can be made to run as well as a older 192T.

Here is the intake - does anyone know what the small hole is for at the bottom of the main intake port (black arrow)? It would open first and close last, so I assume it would spit back a small amount of fuel into the carb throat.

 

[Stackowood]

I'm looking for ideas on simple inexpensive mods to gain some power, other than muffler and timing advance.

Shaving a couple of millimeters off the intake side of the piston skirt would be pretty easy.

 

[bikemike]

View attachment 63027

Hard to tell here, but the new muffler on the right has the deflector recessed back into the body of the muffler. Maybe that was the attempt at a fix? New deflector is also a little smaller.

Is there a volume difference in the 2 exhaust? Imo I think the 200 and 201 benefit from a larger exhaust for performance reasons having a bigger chamber to collect in and rebound to bump compression like a tuned pipe would.

 

[bikemike]

View attachment 63111

Leave it to the 200t horde king to have the pretty 200t saws

 

[bikemike]

I'm looking for ideas on simple inexpensive mods to gain some power, other than muffler and timing advance.

Shaving a couple of millimeters off the intake side of the piston skirt would be pretty easy.

Can you try the older 192t muffler on the new 193t after its opened up to match a 193 and se if any gains can be had?

 

[bikemike]

The supply of good 192T saws is drying up so it's time to move on to the 193T to see if these strato saws can be made to run as well as a older 192T.

Here is the intake - does anyone know what the small hole is for at the bottom of the main intake port (black arrow)? It would open first and close last, so I assume it would spit back a small amount of fuel into the carb throat.

View attachment 71876

To lube the big end. The strato has a devider and typically send fuel n oil to the crank and fresh air to the top side of the piston don't kow if that's the case there but just my guess

 

[Stackowood]

Can you try the older 192t muffler on the new 193t after its opened up to match a 193 and se if any gains can be had?

The 192T muffler does have more volume, but the bolt hole positioning is slightly different so that you cant interchange them. I'm finding a lot of small differences between the 192T and 193T.

 

[bikemike]

The 192T muffler does have more volume, but the bolt hole positioning is slightly different so that you cant interchange them. I'm finding a lot of small differences between the 192T and 193T.

Ok good to know. Is it a wider distance on the 193

 

[Stackowood]

The bolt spacing is the same, it's just clocked differently. So if you put a 193 muffler on a 192 it is rotated a little and there is some interference.

 

[Stackowood]

Looking for some opinions on intake duration ...

http://opeforum.com/threads/part-two-the-intake-port.7290/page-9#post-412121

 

[Stackowood]

I recently bought 2 of the 192T carbs (C1Q-S257) from a well known aftermarket company and here is what I found:

Casting and finish is nice, not rough like some. Both carbs would not hold pressure and had leaking needles. Metering levers were set a little low, and the spring is quite a bit longer than oem.





The fuel inlet tubes were installed at the wrong angle and had to be bent slightly to work, and I installed OEM Zama carb kits. The choke shaft also needs some filing to get the choke lever to slide on.



I wasn't expecting perfect parts for $20, but we'll see how they work when installed on a saw.

 

[Wonkydonkey]

Umm good thread, I learnt lots & and enjoyed reading
Cheers

 

[Stackowood]

Getting back to the 193T project, the goal is to pick up some power with simple cheap mods that will make it run a little more like a 200T.

Here is the degree wheel mounted up to find TDC and intake duration:



Stock intake duration is about 146 degrees and I'm trimming 0.040" off the intake side of the piston skirt to give about 6 degrees more. Easy mods to the piston without getting into a lot of port work.

Piston trimmed at the bottom and also at the fresh air cut-outs:



New intake duration is 152. The intake restrictor is modified, I'll probably advance the timing a little, open up the muffler deflector, and then compare it to a 100% stock 193T.

 

[bikemike]

Umm good thread, I learnt lots & and enjoyed reading
Cheers

Yeah I was impressed with the exhaust being clocked different so you can't swap parts

 

[Stackowood]

On the 193T the piston goes in with this "disposable" ring compressor that Stihl sells for about $0.50. It has to be cut off once the piston slides in.

 

[Stackowood]

The latest version of this saw comes with a muffler that has a larger outlet-



But the deflector and screen are still choking it off -



Modified outlet and larger screen -

 

[bikemike]

We would like to se a stock vs modded saw video when ur done

 

[Stackowood]

Next up is testing 2 new saws: 100% stock, modified, and then modified with added intake duration.

 

[Stackowood]

I'm not really set up to do videos, but I think I'll start with a smart phone on a tripod and see how it goes. Suggestions?

 

[bikemike]

I'm not really set up to do videos, but I think I'll start with a smart phone on a tripod and see how it goes. Suggestions?

It's all I use for vids smartphone with a clean screen makes nice vids and easy to load too