Das MZ Forum für MZ Fahrer

Hi Thank you to all people are help me. Right now I started my ETZ 251/250

Well after 3 year stand. I hear again the beautifull sound of the emmy, but...

I really have to say I dont know how to set my carburetor. When I start the motor the RPM jump to 5000 rpm.

1º- Ok so I need help somebody explain me how setting the carburator.

2º- My motor is a 250 and I guess need other setting because the short exhaustof the 251 model (or is the same), I have the original setting HD etc...

thank u

_________________
Viva Cuba Libre!!!!

What is the manufacturer of the carburetor? BING or BVF? In the Carburetors are Nozzles with numbers, what is the thickness of yours? There are 2 of them, one for the idle and one for the Throttle.

Robert

sorry I forget that date. It is a Bing with the original setting for the 251. My motor is a 250 with the 251 exhaust. Any idea if I need other setting??

_________________
Viva Cuba Libre!!!!

OK, i think u have the Main Nozzle in 118. It is to small. Take a 122er for secure to prevent a jam on the piston and cylinder. Check on the Connections between Suction//Carburetor//Cylinder that there is no way to let air in, that makes the burning better, heater and the RPM higher. Try to spray Parts-/brakecleaner on those connects to check. If the RPM goin down u have the bad connection found. I hope you understand what i mean.

Robert

Ok I undertant what u mean. So I will buy the 122 dose and I will spray with brakecleaner the connection. I know what u mean.

thank u

_________________
Viva Cuba Libre!!!!

Data_sheet

For confusion:
I use a BING in serial manner with a TS exhaust for yers and much km.

Maybe you clean the carb. (incl. all needles) and take care for a correct adjustment.

_________________
Gruesse vonne Parkbank
Alexander

K3 ………...

After that, u have to set the idle-RPM. That is a little tricky and hard to explain in english. I will try:

1st. there is a small screw with that you can adjust the mixture between fuel and air in idle. screw full in and after that 2 full circle out for preset.
2nd. u have to set the RPM stable, for example on 2000RPM.
3. try to find the Point on best idle-gas while you screw it clockwise or counterclockwise to find the Point with the highest RPM. it takes a Moment to have effect on the RPM, it takes time.
4. down the main RPM on the big Screw for the Carburetor piston, then do Step 3 again and again down to your Wish-idle-RPM.

Robert

ok. I understand what I have to make with the small one screw, just complet screw in and then 2 turns complet back.

But what about the Leerlaufschraube. What I understand is that: first I open the Leerlaufschraube untill I find the max RPM. Then I unscrew the Leerlaufschraube and wait a moment untill the rpm go down, then the same untill I get the 1200 RPM.

and then the Luftregulierschraube I keep in this position or something else??

Other thing is when I install the Auspuffrohr I noticed fit not so good and maybe because that I have a air outlet. So I have 2 option:

1º- set one Krümmerdichtung here with the 251 Auspuffrohr.

2º- Or buy one 250 Auspuffrohr and cut it til the same large of the 251 one.

_________________
Viva Cuba Libre!!!!

One question before you adjusting the carburetor- the throttle Valve is mounted in right direction

In worst case it is twistet 180 degrees and thats why it is open also during the throttle is closed. The chamfered side should be rear.

P.S.: Here you find a spanish ETZ251user guide and a ETZ125/150 repair manual in english

_________________
Kleine Anleitung, wie man das Zündschloss einer RT überprüft

Well when I adjust the bing carburetor. The throttle valve have just one direction to choice and fit. thas is because in one of the cylindrical sides have a rabbet, that ensures the correct instalation.

_________________
Viva Cuba Libre!!!!

Sorry, I had overlooked that you have a Bing carburetor

_________________
Kleine Anleitung, wie man das Zündschloss einer RT überprüft

Hello Pepin, any positive happens since yesterday? The "Leerlaufluftschraube" = the small screw; the "Leerlaufschraube" is the Big one. U screw the Big one in to have a stable RPM (for example, 2000RPM); after that u adjust the small "Leerlaufluftschraube" to find the highest available RPM, its like a Gauss-curve. After then u screw the Big "Leerlaufschraube" back to reduce the RPM to example 1500 and try to find the highest RPM with the small screw on that Adjustment again. The fine tuning cause the wrong exhaust u can adjust AFTER your Carburetor works fine - in idle and the moment between idle and throttle.

U have mounted the Parts of the Carburetor Piston correctly? Piston -> Clamp with Needle -> Plastic Part -> Spring...?
U have mounted the Small Steel Wire in the Throttle / steering Handlebar correctly? There is a wrong position available to have a quarter Circle to throttle.

Big Screw = Leerlaufschraube = directly adjust the RPM in idle with the Position of the Piston; screw in = higher RPM
small screw = Leerlaufluftschraube = adjust the RPM indirectly by balancing air and fuel in idle. Screw in = lower air, fat run; screw out = Lower fuel = higher RPM, but lower performance in the moment you open the throttle.

Robert

well I have a doubt now. When I release The cold-starting lever does not easily go back, so I have to help a little. Perhaps the spring is not in good coniciones or I have not properly installed.

_________________
Viva Cuba Libre!!!!