Got to say that your carbs look very clean, almost suggesting that they've been out before and cleaned up, possibly you inherited this problem when you bought the bike !?!
I don't know how accurate your gauges are, it would seem to me that the pipes have pretty much the same amount of fuel in them the difference in levels could be explained by the distance from the carbs to where you are measuring the level being longer from the inside carbs (2 & 3) and shorter from the outside carbs (1 & 4). Rather than visually compare the height of the fuel level I would have thought you'd need to measure the length of pipe from its end to where the fuel level tops out to find any difference. You may be doing that or I may be missing something such as gravity affecting the fuel levels within the gauges.
If the coolant circuit has been bypassed and the 2 blue pipes are connected to the carbs and are not going anywhere you can just remove them, very weird that someone would have fitted them in the first place. You can tell if the coolant circuit has been bypassed by checking the right hand side of the radiator (connection just under the main pipe) and the thermostat housing just above the rad (connection coming off top left), you can see where I have capped the connections off on my bike, I have not bothered capping the spigots on the carbs as there is no point.
![[Image: 26422929566_24ffb58e01_o.jpg]](https://farm2.staticflickr.com/1480/26422929566_24ffb58e01_o.jpg)
I don't know how accurate your gauges are, it would seem to me that the pipes have pretty much the same amount of fuel in them the difference in levels could be explained by the distance from the carbs to where you are measuring the level being longer from the inside carbs (2 & 3) and shorter from the outside carbs (1 & 4). Rather than visually compare the height of the fuel level I would have thought you'd need to measure the length of pipe from its end to where the fuel level tops out to find any difference. You may be doing that or I may be missing something such as gravity affecting the fuel levels within the gauges.
If the coolant circuit has been bypassed and the 2 blue pipes are connected to the carbs and are not going anywhere you can just remove them, very weird that someone would have fitted them in the first place. You can tell if the coolant circuit has been bypassed by checking the right hand side of the radiator (connection just under the main pipe) and the thermostat housing just above the rad (connection coming off top left), you can see where I have capped the connections off on my bike, I have not bothered capping the spigots on the carbs as there is no point.