You guys running without ramair.. are they fuel injected bikes? I'm trying to run my thundercat without the ram air tanks (still have the little stumpy ram air intakes on the frame though) and it really doesn't like being above 50mph. Maybe the carbs need to be pressurized somehow because there was a pipe coming from the carbs that connected to the ram air tank?
First of all, ram air starts working after about 160Km/h (100Mph), thats when the air pressure entering the intake exceeds atmospheric pressure. And you start geting "boost".
Now, on Fuel injected bikes there is a Map(manafold absolute pressure) sensor in the airbox, that will then tell the ECM to adjust fuel delivery.
On Cabureted bikes there are a few different designs, but essentially the same idea. The carb float bowl vents get pressurized too. Same as intake air.
So when you remove the ram air on some
bikes, you have to change vent back to atmospheric pressure.
My buddy had a F3, that ran like shit after he turned it into a nakid stunt bike. That bike has a dual stage float bowl vent system. One for low speed, below 12Mph, and one after. He had to ged rid of the 2nd system.
Another benefit of ram air is that you get "fresh" air at speeds below 160 Km/h (100Mph). Not heated air from behind the engine or under the tank.