EtZ 250 Carb Question

[Puffs]

Mmmm ... I'll do it on the hush hush... I won't tell MZ if you won't...

On heads, where I said I used it too, please realise that many heads have 2 sealing faces: 1 with the barrel and 1 with the rocker cover.

Furthermore, I'm quite sure MZ was oblivious of products like this; I don't think they were available 40 years ago, and certainly not in the DDR (or Russia). Practices change over time, and not all MZ recommendations are still optimal (or even valid). It's up to us to choose our preferred method.

Anyway, I think this horse has now been flogged enough.

[Guesi]

Agreed

[nice2day]

Just to let you know Guesi. I respect every part of the MZ I am restoring. I treat it with utmost respect as I admire the quality of the engineering. I am a bit of a perfectionist which is why every thing I do (apart from eating my dinner ) takes such a long time (years). When I work on a bike I have to try to make everything as perfect as I can, or even make it better as long as the upgrade is in sympathy with the original or unnoticed. My current ETZ 250 has been taken apart to literally EVERY nut and bolt on the entire machine, apart from taking the speedo and tacho apart there is not one screw that has not been removed and 90% replaced with stainless steel items. When I look at the Factory Parts List I think wow, there so many (hundreds) but I have worked on every one, cleaned and refurbished every single part...I have even rebuilt the wheels myself and I try to keep as many original parts as I can and all these are refurbished by myself too. Today I found 5 screws that I will not remove as they seem very difficult to undo (they seem to be glued in?) I wonder if anyone can guess what screws I am talking about ?..one clue they are on the left side of the bike...
Anyway here are a few more photos...it's coming together a bit more quickly now (Thank God!)

Les

[Blurredman]

Looking lovely..!


Boyer Branson ignition?

[Puffs]

Yes it does!

Even a new horn... Did you make the inside of the F hub black? How come all castings (& carb) looks so new? Did you sand (/vapour/?) blast it?

Anyway, seeing this & your previous work, I once again think that when issues arise, you'll solve them adequately.

Even so, I'm quite disappointed that you did not take those 5 screws out. You know the ones I'm talking about...

[nice2day]

Many Thanks Blurredman and Puffs.
Regarding my "Trade Secrets".... All aluminium alloy was cleaned by me. Over the years I have found several ways of getting aluminium clean. Generally I use Phosphoric Acid at some point and if it is very corroded I resort to using a rotary Nylon wire brush. They are red coloured and have abrasive impregnated in them. They are ideal for the wheel hubs as all you have to do is let the brush rotate the hubs until they are polish bright metal. There is no need to paint the the alloy hubs as they stay clean and mostly uncorroded. Nothing is more unsightly than black paint peeling off aluminium. However I did spray the inner faces,including disc hub centre , after acid etching, with a baked on black silk paint as I like this look. All the levers and speedo brackets were similarly abrasively cleaned etched and baked on at about 150 C. Crankcases were acid cleaned and eventually I used wire wool (Brillo Pads) to burnish the outside areas. The head and Barrel were cleaned with a KARCHER sand blaster. It took 2x sacks of "kiln dried" sand but much cheaper than aqua blasting. I wish the sand was touch more grittier though. The worst part is cleaning up the lawn afterwards and getting every single grain of sand out of the parts...
Carbs and stub were done similarly : acid/ stainless soft wire brush/Ultrasonic bath and finished with wire wool. I also clean the steel internal parts with the rotary brush and finish with an acid dip. The phosphoric acid produces a very good anti-rust layer and as far as I know it is the first part of any car body anti-rust pre primer treatment. I will show you the evidence on a seat pan that has not rusted even though it has been damp on and off for 2x years (photo coming soon) All zinc plated parts that were rusty I used a steel rotary wire brush, acid etched and I used a Silver "Hammerite" paint. this hardens off quite well over time...OK it is not as good as re- zinc plating but with some bikes I have actually got them re-plated...it depends on how I think they will wear in use. All bright aluminium I use a 1HP rotary polishing mops and have become pretty good at knowing how to do it but it is a filthy job and I have often started doing it at the spur of the moment and covered clean clothes with black greasy dust, not to mention my entire exposed skin including face (which sometimes makes me think about the melanoma ..who knows) The rims were polished this way before rebuilding them...it took ages.
Final preparation is the tank which was rusted extremely badly inside (over 20 years left outside empty) I used hydrochloric and phosphoric acids and coated inside with TAPOX.
I now have to spray the side boxes so they will be hand sanded and etched with acid then 2K spray paint.
And yes...I tried to undo the 5x screws (I think there were five) so I'll tell you...they are the screws that hold the air box together and I realised afterwards that the box is GLUED together so pointless in getting them out. The inside is perfectly clean and bright anyway....well something had to be clean somewhere...
Les

[Puffs]

Ta Les, on sharing those trade secrets. That all sounds quite intense & a lot of work - but it looks great!

The airbox & filter holder I've had apart too, but thought those were just 3 screws. Anyway, looked it up:

Airbox.jpg (15.02 KiB) Viewed 77 times

Maybe 4, maybe 5 as you say. I think I left those in place too & just sprayed the airbox as-is.

The exposed paint on my 251 was quite a bit bleached, and I actually used the airbox to select the colour closest to the original.