Corsaro 125 in trouble...tricky carburettor

[Gilles.B]

Hello everybody!
I'm writing from France, in English, sorry!

I have some troubles with my recently restored 1969 Morini Corsaro 125 carburattor
It is a Dell'orto MA model
MA20 B3
I have currently the following settings
Atomizer 225
Main jet 95
No mark on the needle ( probably non original)

These settings are probably wrong ( uneven acceleration )
Can anyone tell me the original settings for this carb?( jets sizes, atomizer size, needle size)
No documents available on this point...
Thanking you in advance for reply or any suggestion
Best regards
Gilles

[gk]

bonsoir gilles ,

sorry i can`t give you information about the correct equipment of the dellorto ma 20 b3 . maybe werner wilhelmi has the correct answer ?
some years ago he wrote in “la strega” nr. 57 about the changeover with a dellorto vhbz 22 bs . i know , that is not the needed answer of your carburator-problem . but i think , werner is one of our specialists for older morinis and could help in your problem .
there is no carburator in my corsaro 125 parts-list , why that ?

if you have a chance to change into a vhbz - carburator here is the setting
of werners la strega - article


atomizer 260 k
main jet 105
slow jet 42
choke jet 70
needle e17 (3. mark)
float 14 gr
float level 10,5mm


munter bleiben (veiller)
günni

[Werner Wilhelmi]

Hello Gilles,
first of all: a beautiful bike, good work, really nice. This is a 1968 modell. the first registration in 1969 is ok. In 1969 a new model line with new design came on the market. The models were Corsaro Sport Lusso and Corsaro Super Sport. So this is the last model of the "old" design.
But now to your problem with the carb. There has never been a carb MA 20 B3 for the Corsaro and I do not know details for these carbs. Carbs for Corsaros were ME 18 BS for first modells and touring models and a UBF 20 BS for the later and the sport models. The settings for these carbs are on the list you have added to your email. But parts for these are hard to find.
If you have a cylinder head with 20 mm inlet pipe you can easily adapt a VHB 22 BS carb to the bike. I have made good experiences with these carbs. You need a new selfmade intake fitting with 22 mm diameter for the carb as these carbs have no flange for fitting. I simply adapted the different diameters within the heat protection between carb and cylinder head.
The latest setting of the VHB 22 carb on my Country is:
main jet 98
idle jet 42
throttle 50
needle E17, 2. mark
choke 50
atomizer 260 K
float 14 g, level 10 mm
This is almost the setting of the Regolarita models which had a VHB 25 BS carb and should also be good for your bike. The engine starts very well and runs well at high revs. But because of the great diameter of the carb it is a little worse than a 20 mm carb in the mid range of revs.
Over all these carbs are a good progress for Corsaros.
Werner