Ive got problems with fueling on my hybrid. Cant get it to run right. Its got a modified 3tj airbox on with k&n filter fitted but its running way too lean. I'm now up to a 170 main jet and its better but still lean. Diaphrams look ok in the carbs. Does anyone know what the pipes are for running along the bottom of the float bowls linking each carb as mine are blocked off, does anyone know where they shoul be connected?

I believe the pipes you refer to that are blocked off are normally connected to the cooling system and act as 'carb heaters' on the cat which weren't used on the 400 - i think........!

someone have the cooling route for thundercat carbs?
There are two types of cat carbs? i can see differences in the cooling hoses