I had a set of those which I intended to use on my Bimota with Kawa GPz1100 motor but I couldn't get them synchronised. Either they were synched at WOT and way out at idle or the other way round - it just never worked. I even spoke to an old-timer at the Malossi factory, but I still couldn't get them right.
Eventually I split them up into two pairs of left+right and sold them separately. I then found a set of Mikuni VM33 smoothbores and fitted those.
Fact is these Malossi-reworked Dell'Ortos were never designed to be ganged up into a cluster of four.