Stihl Contra Info Sharing Thread

[omega_supreme]

Cool! I hadn't noticed yet that you uploaded that pic. Is your saw of this generation (07 spikes, different/smaller sprocket cover and green hose)?:



I wonder if that's the first version they made. My earliest manual/IPL is from 12-64 and that version is already newer that the one shown in this ad. It has the two piece muffler by the way, so I think you were right several pages back in this topic.

 

[WoodBoss83]

This kind of bag?

View attachment 404950

Yep! It's very similar to that bag.

 

[Bill G]

Yep! It's very similar to that bag.

Hello Nick,

I see you just posted 28 minutes ago. I just sent you a email 19 minutes ago. Hopefully you got it as I have sent others also

 

[scallywag]

Cool! I hadn't noticed yet that you uploaded that pic. Is your saw of this generation (07 spikes, different/smaller sprocket cover and green hose)?:



I wonder if that's the first version they made. My earliest manual/IPL is from 12-64 and that version is already newer that the one shown in this ad. It has the two piece muffler by the way, so I think you were right several pages back in this topic.

I've not seen the smaller bar cover.

 

[omega_supreme]

Here it is:



(note that it does not cover the sprocket area all the way down, unlike the later version)

 

[scallywag]

Interesting pic!......Note the starter cover on that saw, first I've seen of that style on a G.

 

[Steffen]

I have been talking about useing the 090 piston in a Contra S cylinder, no one seem to have done this before, and i was told this will not work... im doing it then!
I have been useing a part saw that is one of the late ones build, is has the 090/070 crankcase and the S cylinder fit down it then.

It got a new alu muffler, a new 090 carb and a new 090 piston.

Put some Aspen in the tank and this is what happened...

 

[scallywag]

Nice work Steff! ....Please let us know how it runs when cutting.

 

[Steffen]

Will do. I let it idle for 15 min. After that it revs up very fast! seems faster than my normal S.

 

[Eddy_t]

Will do. I let it idle for 15 min. After that it revs up very fast! seems faster than my normal S.

Told you it would! As for the acceleration, I believe that's due to how the transfer of gas due to the piston shape is achieved. The windowed S piston would push it sideways, whereas the 090 piston feeds from bottom upwards - less turbulence from directional change.


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[scallywag]

Lets just wait and see how it pulls under load!

 

[Steffen]

I put the Contra S in some wood today, runs great!
In the video you can se the chain runs hot, need to find out why. The oiler seems to work fine.
It revs nice in the 3. cut, this 090 piston might work better than the normal S piston.

What do you think??

 

[Eddy_t]

I put the Contra S in some wood today, runs great!
In the video you can se the chain runs hot, need to find out why. The oiler seems to work fine.
It revs nice in the 3. cut, this 090 piston might work better than the normal S piston.

What do you think??

So would you say it's more, less or equally powerful with the 090 piston?


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[Steffen]

Its a bit hard to say. It revs better and has higher rpm. But i have an 090 carb on it, and its bigger then the normal S carb.

But it feels like it runs better with the 090 piston than the normal S piston. Also a bit better than my 090GS, but the 090 has higher compression than the S and might have more power. But the S with the 090piston seems to rev up a bit better. Without that beeing a good thing though.

Dont know if this makes sense to you??

 

[Eddy_t]

Its a bit hard to say. It revs better and has higher rpm. But i have an 090 carb on it, and its bigger then the normal S carb.

But it feels like it runs better with the 090 piston than the normal S piston. Also a bit better than my 090GS, but the 090 has higher compression than the S and might have more power. But the S with the 090piston seems to rev up a bit better. Without that beeing a good thing though.

Dont know if this makes sense to you??

Hmm, I don't see how a better pick-up can't be a good thing.

The carburettor make no difference to how the saw runs, because regardless of Venturi size or jet flow, the saw will always require the same fuel to air ratio given set constraints.

Compression is power, but comparing a gear reduction saw to a direct drive saw won't give an accurate idea of power gains from a piston.


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[Steffen]

Yes the carb has a differens. Adding a bigger carb makes the engine breathe more easy, and that makes it possible to get more air and fuel pr stroke.
Try breathing truth a straw or a larger tube.
I have been tuning a lot of mopeds some years back. A bigger carb and intake has always made a differens.

 

[Eddy_t]

Yes the carb has a differens. Adding a bigger carb makes the engine breathe more easy, and that makes it possible to get more air and fuel pr stroke.
Try breathing truth a straw or a larger tube.
I have been tuning a lot of mopeds some years back. A bigger carb and intake has always made a differens.

A larger Venturi carburettor creates a leaning effect. Volume for volume, there is no difference in fuel/air.
And in terms of two stroke tuning, a leaner mixture is faster, more powerful and hotter. The carb makes little difference to a correctly tuned stock saw, especially between the HL112 and LB-S9 carburettors on the same 137cc engine, maybe on a 90 or less cc saw.


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[Steffen]

I need to adjust the ignition timeing on one of my Contras. Have any of you done it as it is descriped in the service manual for the Contra? If i have got it right, the crank has to rest on the crank locking tool in the crankcase and the gap in the points is then set to 0,4mm. Im i right?

 

[Eddy_t]

Yeah, I have when I rebuilt mine, but you need a tool to measure from TDC


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[Steffen]

Well, what tool did you use? The sparkplug hole is not at the top of the cylinder its from the side, Its not possible to measure the TDC from that i think.