Scorpion Tour looses power after 2 km drive

[Henry74]

Hi all,
I am new to MZ but not to motorcycles. I just purchased an MZ Scorpion tour with 16000 km. It has been sitting for quite some time at the dealer.
In fact when I went to check it out I brought my own fuel since its tank was dry. I knew the dealer so no big deal there
Yesterday I gave it a proper run. It revs clean past 7000 RPM until the ignition unit cut out kicks in. And for the fist 1.5 km or so it does run ok.
approaching the 2 km it looses power (it still revs up to 7000 but it sort of hunts for fuel) it starts to pop too (fuel starvation = leaning out = combustion is not complete in the cylinder,hence it pops).

Then when I stop by the curb it stops completely. I wait 30 sec and it starts again. definitely its a fuel problem.

Yesterday I took the carb out and noticed that the fuel float stem is cracked. I did repair it successfully with Solder Aluminium.
I need your help guys now.
I heard that there is a small fuel gauze , but I do not know where to find it.
Also what is the float bowl height setting.
what should I look for i.e. I do the general cleaning but is there anything in particular I should look for?

p.s. I need to check the fuel tap too there is a filter if Im not mistaken.

The repair has been done this morning just before going to work, the Solder need a bit of clean up but it is strong which I am glad .

You can copy my pic and draw arrows and comments as you wish, I appreciate any help.

best regards Henry from sunny Malta.[size=150][size=150][/size]

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[breakwellmz]

Is the air vent in the fuel filler cap clear?

[Henry74]

I have to check. I noticed a nipple under the tank, I assume that it is the airvent no? Shall i blow trough this nipple to check if it is clear.

thanks for your suggestion.

[Chuck in Indiana]

Sounds like a fuel delivery problem all right. Petcock clear? Needle and seat sticking?
"I heard that there is a small fuel gauze , but I do not know where to find it."
From memory.. under the needle seat. You'll find it when you replace the needle and seat. I picked up a new kit with gaskets and o rings from Poland. About 2 weeks delivery to the US.
"Also what is the float bowl height setting."
25-27 mm.

[DAVID THOMPSON]

filter located at end of red arrow in picture
below the brass thing

[dandywarhol]

filter located at end of red arrow in picture
below the brass thing

Be careful taking it out - it's a push fit but the "O" ring can make it bind and you may end up damaging the brass needle valve holder. I soaked some silicon spray down it to help it out and used a pair of long nose pliers with cloth between the jaws to avoid scratching it. A wiggle and pull and it should come out. Also might be advisable to have a gasket/seal kit handy in case the rubber "O" ring is brittle

[Henry74]

Thank you all for your replies.
I did not manage to get the brass fuel outlet bush but since the fuel pass trough it from the fuel inlet I did wash it well with acitone blew it with air and finished of with carb cleaner(acetone) again

I cleaned every orifice with carb cleaner too.

I checked the the airvent breakwellmz and with the help of my teenage son fuel is flowing well (compared it with an open fuel tap too )

the problem seems that the fuel float closes at 30mm and chuckinIndiana advised that it should be around 25 to 27 mm . so it seems that it is closing way to early no ?
Fuel in the bowl is low and that might lean the mixture. what do you think guys.

ps the solder aluminium did not work, but I applied putty by jb weld , it says resitable to oil gas(petrol) and diesel and bonds with ali. do not use it on cabs guys.

[Henry74]

Hi all.
Yesterday I reassembled the carbs fitted them on the bike.
Did all the checks you suggested and am glad that it ran perfect till 140kph with power reserve for more.

the only downside is that the calipers are weeping oil, gimeca 4 pots and am thinking of buying brembo ones.