If you mean the black plastic pipes linking each float chamber - these balance the fuel levels across each carb......if you mean the horizontal rectangular metal pipe with four vertical metal circular pipes on its underside.......these were possibly part of an anti icing mechanism to prevent the carbs icing up in the winter. I think the system warmed the carbs which were prone to icing up once the fuel started to flow on really cold days. The system may have been called 'KTRAC' so ask your local Kwacker dealer about it.
I had a Kawasaki ZXR1200 around 2002 which had an anti icing system fitted......couldn't tell you much about it as that bike always ran like a dream, and apart from the Dealer doing the servicing as I bought it new and doing the routine maintenance stuff myself regularly as it was a commuter, I never had any cause to work on the fuel system. That bike was certainly one I regretted selling.
I was chasing a Dealer in Minnesota some years ago and asked him when he was going to ship a bike to me.........he said that he'd been a 'bit busy' as the temperatures had been around MINUS 25 for the last week or so......that's why anti icing systems were introduced for bikes and snowmobiles I suppose.