New TS125 owner

[Kruh]

You could also just loosen the brake and throttle housing and slide them both to the left, which will expose the cable.

[AndyP66]

So I have managed to change the throttle. But the carb is still over reving even when the throttle is fully closed.

What am I doing wrong.

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[Blurredman]

From what i've been told the TS's use carbs without slide stops, just like my ES250- therefore, what happens when you twist the throttle closed further than normal?

Additionally, as others have said, there you could simply just have an out of adjustment carburettor slow speed screw, or need to adjust the cable adjuster at the top of the carb, or indeed false air.. Spray brake cleanerr or WD40 around integral parts to see if combustion changes. Base gasket, carburettor top screw, inlet join of carb, inlet join to barrel. Even the headgasket?

[AndyP66]

So looking at replacing the carb completely as they are not too expensive.
My MZ is fitted with a 22N1 carb. The only one I can find is a 24N2. Is there much difference

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[AndyP66]

I'm not sure what a 24N2 carb is, possible a later version of the 24 N 1-1 & similar to that.

The manual prescribes the 22 N 1-3 for the TS125 & ES125, and the 24 N 1-1 for the TS150 & ES150, the latter with a 24mm venturi, vs. 22mm for the former.
In the Spareparts list (Ersatzteilkatalog für die Motorräder TS 125 und TS 150) the two share the same pic:

24.gif

Screenshot 2022-08-14 at 09-32-33 Ersatzteilkatalog MZ TS 125_150 - Miraculis.png

And seem to differ only in body & jetting.

However, for the intake manifold different models are specified: 12-42.021 for the 125, and 14-42.025 for the 150; probably the mouth of the 24mm carb is a bit bigger.
You might get away with using an adapter (possibly just a d=1mm piece of alu??), but jetting may be impacted by the smaller intake manifold & also require adaptation. And if you don't make & seal that adapter properly you'll have false air. So maybe better also buy the proper intake manifold.

Are you sure the high idle issue will be solved with a different carb? For instance, have you found a clear problem in the old one, like a crack, or very significant wear, or so? Surely you can make the 125 run well with a 24mm carb, but you may have to adapt the jetting & other things, and chances are that your problem is not actually due to the carb (in the sense that there may not really be anything wrong with it).

What results did the earlier suggestions have?

Giving up on the thing to be honest.

Changed the throttle cable and now it’s worse. On start up it’s goes straight to max revs if the throttle is wide open. Thought it would be easier to change the carb

[Blurredman]

Did you measure the length of the cable as well as the sheeth length and make sure they were the same?

If you were near i'd come and help! But unfortunately that isn't the case.

[dave47]

Fyi,. The throttle cable for the 22N1 carb and flat bars is as follows:
Inner - 945mm
Outer - 840mm.
I would remove the carb from the engine and check the needle and airslide are moving correctly as the throttle is turned

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[AndyP66]

Thanks both for the info.

I do agree, with it being the slider. As I have said before my knowledge and skills are very limited and I am not sure if I have put the slider back correctly when I changed the cable. The Haynes manual isn’t very good when it comes to the carb.

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[Blurredman]

Certainly my 28N1-3 carb on my 250 has no such pin to stop rotation of the hollow slide, unlike the 30n carbs- however, it is obviously ovalled in such a way that prevents the rotation after installation.

I've not had any experience with the 22 or 24n carbs (or 125/150cc MZ's) but it might be the case above- it's definitely the correct orientation on the X, Y and Z axis?

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[AndyP66]

Well, I have no experience with these carbs, and they may or not have that pin/groove. True, flat slide Mikuni & Keihin don't either, but round slides normally do.

To get clarity on this issue, I had a look at the original manual on Miraculis.de, as well as in the "MZ_TS125-150-1983-Official_Service_Manual.pdf", which both give a long section on it (Chapter 6, which I wholeheartedly recommend you read). The slide does look quite cylindrical though, and fig./Bild 124 does appear to show a groove. But it's not a clear picture.

Note there is a long section on how to use & set the starting feature, by rotation of the throttle handle.

I must be honest I don’t recall seeing a groove in the slider for the carb.
Do you have a link to the manuals you mentioned.