MZ/MuZ Riders

Hello!

My ES 250 is running "ok", but l thought I would give the carb a good clean-up since I have some problems with getting a stable tick-over. The carb was clean inside but the floatlevel wasn't according to the book. But I discovered tha the needle was "stepped"? I've not seen that before on any of my bikes? Should it be like that?

Sounds like you have fallen foul of fixing something that was not broke !

A stepped needle is usually a worn needle.

Sounds like you need a replacement needle and if you replaace the needle also replace the needle jet as both can wear and they are not expensive to replace.

I would replace, and double check the fuel level.

The needle was stepped i 3 different steps, each step has the same diameter. So sure it was ment to be so
But yes, I think its the best solution to buy a rebuild-kit for the carb, if its available. The reason it want to clean the carb was because of poor tick-0ver. I thought may be the idle-jet was clogged.... But nope!

TJBERGLI wrote:The needle was stepped i 3 different steps, each step has the same diameter. So sure it was ment to be so
But yes, I think its the best solution to buy a rebuild-kit for the carb, if its available. The reason it want to clean the carb was because of poor tick-0ver. I thought may be the idle-jet was clogged.... But nope!

Dont uderstand, if it is stepped the diameters will be different otherwise how can there be a step?

Perhaps I am mis understanding could you post a photo perhaps?

My english is not the best, I'm from Norway. But I'll try to explain it. The needle has 3 different diameters, at the lower end the first 1/3 of the lenght has one and the same diameter. Then there is a clear step up to i bigger diameter for the next 1/3 of the total lenght, and the last 1/3 of the lenght has an even bigger diameter.

I' ve ordered a rebuild kit from Gusi i Germany for 22 euros. Ihope that will do the jobb

The stepped needle is for the 17,5 PS (horsepower) version of the ES 250/2.
The later 19 PS model had a "normal", conical needle.
So if you have the 17,5 PS version, you have ordered the right repair kit

How do I know? Mine is a 1969. May be the stepped needle is the right one?

Hello

What is written on your carb ?

28N1-1 or 28N1-3 ?
The stepped needle is for the 28N1-1, the conical needle is for 28N1-3.

Does your intake gasket look this way :
https://www.guesi-motorradteile.de/pic_ ... CI0091.JPG
you have a 19 PS cylinder.(for carb 28N1-3)
If the hole is oval, it is a 17,5 PS cylinder.(for carb. 28N1-1)

TJBERGLI wrote:My english is not the best, I'm from Norway. But I'll try to explain it. The needle has 3 different diameters, at the lower end the first 1/3 of the lenght has one and the same diameter. Then there is a clear step up to i bigger diameter for the next 1/3 of the total lenght, and the last 1/3 of the lenght has an even bigger diameter.

I' ve ordered a rebuild kit from Gusi i Germany for 22 euros. Ihope that will do the jobb

Not a problem - your English is better that my non existent Norweigan !!

Now that the needle has been explained by others with more knowledge than me I understand, must admit that I have never seen a stepped needle before so you live and learn.

Hope the rebuild kit fixes your problems "lykke til" and "beste ønsker" as I believe they say in Norweigan.

I've just checked the carb and it's a 28N1-1, so the stepped needle is the right one. And so is the rebuild kit l've ordered. Hope this will give me a more stable tickover

Try to run it on real gas the ethonal added fuek ruins carbs
Dave