Topic: CB400F possible air filter/carb issues?

[Slams77]

I have a 1977 CB400F that I purchased last year; with a screen mesh on the air box in place of the air filter.  It runs o.k. until I start to get on the gas around 4000 to 7000 rpm in any gear, at which point there is a loss of power (almost like the gas gets restricted).  Could this be due to the air filter missing or maybe something to do with the carbs not being dialed in to compensate for the missing air filter?  I’d like to do as much of the work on my own, so if there is anything I can do to test it I will definitely give it a shot.

[Kevin400F]

Absolutely, the lack of an air filter could cause the bike to run very poorly.  Easiest test would be to install an air filter and see how it runs. 

Mine even runs a little wierd when the lid is off the filter housing, so I know it would fall on its face completely if the filter was missing entirely.

[Slams77]

Thanks, I'll try that first.