New exhaust....

[difflock]

Thinking about a new exhaust for my MZ ETZ251....

mine is rusty, battered and generally tatty....

now I've considered the full Expansion Chamber exhausts from TKM, or any similar ones.


Do they require re-jetting though?

[DAVID THOMPSON]

do not forget MOT insp....time
dave

[difflock]

do not forget MOT insp....time
dave

as long as its not TOO loud, and it hasnt got any markings on it (not for road use), it will pass

[Guesi]

They are only loud, but have less power than the original ones...

Guesi

[Old Dog]

Don't waste you money, Fred Rodgers will sell you a replacement for surprisingly little and no loss of power. The one thing MZ understood was exhausts.

[Guesi]

The problem is that there are no original exhausts available for ETZ 251 or ETZ 250. Only cheap hungarian reproductions,and their quality is poor.
In germany these exhausts are about 50 Euro.
I have produced an exhaust for the ETZ 250 (100% original and in good chrome quality).
The inner parts of the exhaust are very complicated (as you already wrote:The MZ guys were good in exhaust constructing).
So the reproduction is very expensive.
The exhaust costs 150 Euro. I sold about 30 pcs and all customers are very satisfied with the quality.
But cheap and good quality is not possible....
And this exhaust is only for the ETZ 250, the ETZ 251 was about 10-15 cm shorter than the one of the ETZ 250.
Reproducing this ETZ 251 exhaust does not pay becaue I have to order 600 exhaust minimum, and the ETZ 251 are not that often to find.....

GueSi
www.mzsimson.de

[difflock]

I have an ETZ251, so unless I'm mistaken, your exhaust isnt any use


as for MZ knowing about exhausts, I FULLY understand it.....I've spent quite a few years reading various books and other sources of information about expansion chamber exhausts and pulsejets (including building a few pulsejets myself)

However, I cant see why the expansion chambers from the likes of TKM/Burwins would REDUCE the power.
If they are designed correctly, they will improve the power/torque in the powerband (perhaps sacrificing a bit outside of the powerband)

[Guesi]

That´s exactly the problem:
They are not designed properly, but simply and cheap.And not for a specific model...

Guesi

[difflock]

Ah right, thats fair enough.


I might think about designing my own exhaust.

I have access to a number of tools (including a mig welder), so its just a case of doing some calculations....

[Guesi]

Here in germany there is a guy who dismantles the original exhaust, pulling off the rusty chrome cover and covers the exhaust with a new "stainless steel cover".
It looks a little bit different than chrome, but you have the original internals...
Price is about 100-120 Euro in exchange of your old original exhaust.

Guesi

[DAVID THOMPSON]

the Germans are good at 2 smokers
as an example there was a moped about 1950 to 53
the name started with the letter L i can not remember its full name
it was an add on pony motor hung under the pedal cranks
it was a 2 stroke diesel 18cc .8 hp no spark plug no injector had a carb.
variable compression by moving the head
and was ran on a mix of gas, diesel ,and kerosene and a bit of 2 stroke oil
a bit stubborn if the fuel mix was not correct
but 350 miles per gallon you say
dave
and yes i rode one once .... a bit slow but it beats peddling

[Guesi]

It was called "Lohmann"...

Guesi

[DAVID THOMPSON]

for those that like to read about odd stuff
look here at bottom of page
http://www.dieselbike.net/oldproduction ... uction.htm
dave

[difflock]

Yes, I know of the engine you mean.

VERY similar to the model 'diesel' engines you can get for model aircraft.

great little engines, and quiet even without a silencer....




to be 100% honest, if the MZ engine decides its not going to work properly, I will more than likely fit a small diesel in it....

diesel bike.net is very interesting (I've read it before )