76' kz900 w/pumper carb

i just recieved a 76' kz900 that had been lightly modified. pod filters, electronic ignition, 4-1 exhaust. couldent find my carbs in any of my books. after some resurach found they are from a kz1000. not sure if they are 26 or 28mm ones yet. why would they have been put on this bike. any ideas. what kind of performance changes would it make. i'm in the process of bringing it back to life after 20 years and 8 bent valves...

I replaced my 26mm carbs on my 900 this year with a set of 28mm pumpers and noticed a significant performance increase. The problem is, I cant say that I know for sure that the 26's were set up properly for my bike and the mods I have. The 26's were rebuilt 2 summers ago by a local bike shop (Never do that again) because one of the carbs were leaking heavy out of the overflow. Not sure but they probably used a stock jet kit. Still wasn't getting the performance I expected so I bought a set of 28mm pumpers off Ebay, sent them to Wired George for rebuild, re jet, and removed the pumps so I wouldn't have to worry about the tiny passages in the pumps getting clogged latter. And "WOW" now this bike is starting to do what I new it could.
While removing the overflow tubes off the 26's to put on the 28's I found that they brazed the overflow tube, of the offending carb, solid from the inside!!! Now I have a extra set of carbs to dismantle and learn how they work so I can rebuild myself the next time.

i've seen several people remove the accelerator pump, from their carbs. why...advantages and disadvantages of these over factory ones.

does anyone have tuning info for these carbs. my book only covers the kz900 which this carb did not come on.

The way it was explained to me is that in the early 80's when they started using the 28's on the 1000's they used smaller jetting to make them more emission friendly and to compensate for that they added a accelerator pump to give them a off the line boost. And if properly re jetted the pump was not as necessary. Not to say it wouldn't be a bones. The reason that I removed mine is, I was told that the passages in the pump were so small that they get clogged easily, therefore less maintenance if removed. I cant say which jetting was used on my rebuild but I see a lot of posts on here about jet sizes used and hope to do a lot more learning about that myself.