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What is the difference between MB and UB Dellorto carbs ? I seem toi remember MB's were used on 2 strokes but i cant see why that should really make a difference ?
TIA

Paddy

The Dellorto for a two stroke has a shroud around the front of the needle jet.

Is it fixed or an addition ?

You can push it out and fit the flush type, that the 4 stroke use.
I had a 41mm 2 stroke version on a 360 Bulltaco, and changed the brass piece with the shroud to the flush one, to fit to a 450 desmo.

OK cheers for that, i wonder if that is the only difference then between an MB and a UB.... Seems odd to change the designation on the body because of a removable addition ?

The accelerator pump was blanked off, had a choke, may have been others that I don't remember, but that was all I did to have it run well on the 450.

I think we are talking cross purposes here
The dellorto 1960's UB24 i have has no accelerator pump, neither does the MB24 i have , they are prehistoric Most 450s were running VHB or PHF in the 1970s ?

the only Ducati with a PHF was the 239 sold in France

Eldert

Yes i had a 239 for a while with a PHF30, a lot of them ended up over here as they didnt sell well in France., you would surprised how many 350 and 450 are running about with PHF 36s on

Not an expert but I thought the MA/MB carbs came first and the UA/UB carbs were the next development.

As to 2T vs 4T, it is not just a matter of atomizers and shrouds, the atomizer air bleed is different as well.