ETZ 250 engine to ETZ 251

[Teemu]

Hello!
With too much trouble on my own engine, I have considered changing the engine to my bike. Unfortunately it looks like the only available engines here in Finland seem to be those from 250 model and my bike is 251.
I do not know if it will fit directly to the newer bike. Is it just bolt-off, bolt-on job or do I have to do some changes to the bike?
The thing that mede me wonder this is that trouble with the clutch and gears do not seem to end. Now I lost the third gear totally from the bike. And as the weather is still good I would not like to stop riding yet.
Is there any place in Germany where I could buy a new engine to the 251? I have heard that there are still original new engines on sale somewhere.
If I have a spare engine I could take my engine in to pieces and try to fix it and still ride the bike.
Thanks
Teemu

[torbiaz]

Teemu,

first: yes, you can implant an 250 engine into a 251.

but:
The 250 engine used to work with that very long exhaust. The smaller 251 got a shorter and "tighter" exhaust. Therefore, the steering times have been changed in the 251's cylinder. That's why 250-cylinder and 251-exhaust don't work together well (and vice versa). So you need to use your original 251 cylinder (maybe change the piston as well...?) and you must change the small chain wheel at the engine "exit". This also differs betwwen 250 (18" rear wheel) and 251 (16").


That's all.

ps: the rest of the engine is completely equal between 250 and 251.

[trabimotorrad]

Normaly the ETZ250Engine has no electronic-ignition, but you con either build in Your electronic-ignition, or use the older ignition.
The Exaust-system-problem ist not so big, perhapes the ETZ251 with the ETZ250 exaust run not so good, but yuo mus try.
I drive many different MZ-exaust-systems (from ES, TS, ETZ...) on my MZ, the difference dosn´t matter.

[Teemu]

Hello.
Thank you for the answers.
So if I take the piston and cylinder from my bike and put them to the ETZ 250 engine, it should work.
How much work is there if I get an engine with the old ignition system? The main difference in wiring the system? Maybe I should take the elecric ignition from my bike also.
Or if someone has a 251 engine in good running condition I might be interested in buying one. A fellow MZ rider got a totally new engine for his 250. So they have made some extra engines in the past.
Maybe I should take a holiday trip to Turkey and try to find a Kanuni 301 engine....

[Guesi]

Hello

The easiest way is to change the cylinder and the piston from the ETZ 251 to the "new" ETZ 250 engine.
And the Alternator with the electronic ignition.
That`s all.

There are no new engines available here in Germany, and if you find one,The bearings are GDR made and the sealings are old and hard, so you would have to change them.
And Kanuni ended the production of the 2 stroke motorcycles many years ago, so there are also no new engines in turkey. And if you find one there, they don`t have a very good reputation about the quality....
Not comparable with the GDR engines.
And the last price I know from Kanuni engines is about 1200 US Dollar...

GüSi
www.mzsimson.de

[Teemu]

Hello.

So I can forget the new engines and focus on finding a deasent old one that is in better condition than my engine.
Not so easy.
Its kind of sad that the engine fails now when the rest of the bike is still in condition and also I spent this year quite a lot of money on it. But nothing lasts forever, even MZ will break down someday.
Now the only thing to do is to deside weather to fix my bike with "new" engine or buy some other bike.
Tough question because I kind of like the MZ. it has been with me for 19 years already.
Well, I have to think it over.
Thanks for the anwers.
Teemu

[Emmendieter]

Hello.

So I can forget the new engines and focus on finding a deasent old one that is in better condition than my engine.
Not so easy.
Its kind of sad that the engine fails now when the rest of the bike is still in condition and also I spent this year quite a lot of money on it. But nothing lasts forever, even MZ will break down someday.
Now the only thing to do is to deside weather to fix my bike with "new" engine or buy some other bike.
Tough question because I kind of like the MZ. it has been with me for 19 years already.
Well, I have to think it over.
Thanks for the anwers.
Teemu

In Germany are some good MZ Dealers who should be able to send you a regenerated engine. Have a look at the Linkliste. A good dealer i can recommend Motorrad Ente. Lets call him. Im sure he can help you.

best regards Steff