ala Clyons8 style (not mine) just pick up 4 sets off a bike shop so I have some spare parts. Can anybody tell me about them, What size A would you jet them for? (I would like to dabble on my A14), there's very little sptamped on the carbs themselves, measured the butterfly's at around 35mm.

Look like a set I got if fzr 1000. But mine 38mm. I wanted 40mm as per clyson advised.

Good score. The front set look good with round solid pistons.

Drill the jets to 1.5mm and see. Im drilling mine in my l18 to 1.7mm possibly 1.8.
Read up on bogg brothers stuff

I had 40mm mikuni racing flat slids on my a14, they where good up top but to big for low speed. 35 or mybe 38 you want the car to get out the hole quick

Two sets have brass pistons and the other two have plastic, I'll pull apart the third one to get a feel of how they work ect. While looking on the net for some info it struck me that I bought a whole heap of manuals from the dump years ago and a bike one was amongst them, and waddya know, Yamaha XS1100 is among them with a section for these model carbs hahah.

I ran 40mm mikuni racing flat slids on my a14 also and were smooth all the way through the rev's. Still have the set up in my hoarding box

34s fine for a mild A14 or 130-140hp max all been perfect
38s on an L series think about twin hitachi 38s vs L18SSS
2 more extra 38s now less resonance issues, better response,
more torque & power setup properly compared to the SUs.

There is a KA24DE 2.4L running beautifully with R1 carbs

https://www.youtube.com/watch?v=-Bm_kN25WmQ
first start
https://www.youtube.com/watch?v=ptZW68fahPI
exhaust sound
https://www.youtube.com/watch?v=ybEvBdp3AVs

Depending on needs a 4 x 34mm can flow enough for 90%
of applications for the A series which usually are around
90-140hp ate depending on whats in your wallet.

A supercharger with a single 38m can likely also make 130hp

If I can't make 100hp atw with four of these and some nice mid range I'm going to spit some serious dummy. I noticed a few golf/rabbit blokes run bike carbs well

Round slides?

These are like an SU, great start. What are the other specs of the engine?

60thou over, 1mm dish pistons, h75 unported,, 4-2-1 2inch, not sure on can specs but decent overlap and no power under 2000 so not worth trying. Over 4 is pretty good. Carby right now is 38/38 edges on modified manifold. Been playing with the jetting since my last dyno run so it'll be right up near 100hp atw. Scalloped crank and lightened a12 flywheel

You must shave that H75 head till you get kidney shaped chambers
this will also improve your compression but essentially the open
chamber is horrible for performance and hindering your quest