I have a 1983 Suzuki GS850GL and lately I have been having some issues. It started out with the bike not being able to go past 75 MPH. Turned out to be the boots from the air box were restricting airflow to the carbs, so i cut out the flaps that are in the air box and the bike now goes over 75 MPH, but now it bogs down when you accelerate with more than 1/4 throttle. The bike idles fine and revs perfectly with no load. I replaced the boots today, but still the problem remains. I am at a loss and i don know what to look at next, any help would be appreciated. Also if I give less than 1/4 throttle the bike accelerates fine, i removed the air filter and still the bike bogs down. There is also no aftermarket or performance parts on the bike it is all stock. Recently replaced petcock.