Twin Carb or Single on 500 dommi ?

... that twin carbs are only useful if you want the absolute ultimate power. At anything other than wide open throttle they're just a nuisance. A single carb will give better performance and economy in everyday riding. In my opinion of course.

Hello again Wayne - beware......there are two twin carb manifolds available for Dommies with pre-semi-downdraught heads.  One for the small valve head has 1.5 inch centres, for the vertical mounting studs.  Whereas the big inlet valve head has 1.625 inch centres to accommodate the larger inlet valve.  Twin carbs on the early 88SS, with the pre-downdraught head, gave good performance.  However the 88SS had several other performance improvements so the benefit may be marginal without the other features, especially the camshaft and bigger inlet valve.  As mentioned several times recently,  in the forum topics, the early 500cc Dominators prepared for racing in Daytona did perform very well without the SS cam and big valve head.  They did have a cam known as the "Daytona cam"  and AMAL GP racing carburetters with h/c pistons etc.  There is a lot of relevant information included in the Dominator Service Notes on the on-line website.  Cheers, Howard

Twin carburettors might well make the bike livelier and faster.  That's what happened on my 650 Triumph T110 engine (in a Triton so that's OK).  It also cured a mixture bias toward one cylinder.

If you like tuning and experimentation, do it.  If you wish to avoid fiddling with screwdrivers, or can't do a plug chop, don't.

There is probably no need to splay twin Concentrics, to get them onto your cylinder head.

I've swapped my 88SS back and fore from single to twin.  The twin carbs give it more urge, especially on hills.  But it's personal preference.  As we all know, if you want out and out performance you buy a modern machine.  I like the look of twin carbs and surely the look is important?  Changing is a bit tricky...cables and studs especially 
If you add another, the settings should stay exactly the same as your single.

Twin carbs using a similar manifold block as shown were an optional factory fitting between 1957 and 1961 on the 500cc engines and up to the end of 1962 on the 600cc bikes.  Though quite a few budding race lads had experimented with their own variants before that time.  See picture.

I rode ​​​​​ my 99 to work and around  Europe for nearly 30 years, For the trip to work, I put the twin carbs on the standard 22707 head which made it similar to a 1962 99SS and very fast but still fairly economical.  However, I found that the twin carb cables were constantly changing tension and requiring a carb retune every couple of months.
For touring, I fitted the single carb manifold which gave easy starting, plus consistent slow and fast running.  All echoing Ian's posting above.

As Howard points out, there are two versions of the twin carb manifold about but the earlier 1.5" type (for the T2225 head) can generally be opened out for bigger carbs and the mounting holes slotted for fitting to the later (22707) head.

I too have one of these manifolds on the shelf where it will be staying. Over my many years of Domi ownership the only benefit I have found of twin carbs is cosmetic and bragging rights. For all practical purposes, a single carb is the way to go. I even raced an 88 with a single carb quite successfully.