Removal of air cleaner increases performance

I've been struggling with a poor performing CB650 this summer. I just tried
it without the air cleaner, and it goes like a muck-a-luckin raped ape.

Any ideas why this would be? It seems that if God wanted it to run better
without an air cleaner, he wouldn't have made the factory put one on.

My suspicion is that the mufflers rotting from the inside out could have
something to do with it. I repaired the outside of the mufflers, but I know
at least two have leaks inside. Am I barking up the wrong tree here?

Thanks.

-Bret

 >From: "Bret Taylor" poe.DeleteThis@europa.com

 >I've been struggling with a poor performing CB650 this summer. I just tried it
without the air cleaner, and it goes like a muck-a-luckin raped ape

Do you mean that you took the air filter element out of the airbox, or do you
mean that you took the airbox off?

Old paper air filter elements do get plugged up, greasy, and restrict airflow.
The maximum allowable pressure differential across a filter element is probably
about 1/4 to 1/3 of a pound. More than than that, and it's too plugged up to
flow enough air to the engine.

We had special manometers at work, rigged to check the
pressure differential across certain filters on industrial equipment...

Airboxes and exhaust systems are designed to complement each other at certain
engine RPM. De-restricting the exhaust system (or having exhaust system leaks)
is going to change the RPM at which the exhaust system and the airbox work
together.

Having the internal baffles fall out and rattle around and having all the
fiberglass packing blow out of the muffler will change the "back pressure", and
the pipes and airbox won't work together at the right RPM, either...

 >Any ideas why this would be? It seems that if God wanted it to run better
without an air cleaner, he wouldn't have made the factory put one on.

God doesn't work at the Kawasaki factory. He works for Yamaha now...<!-- ~MESSAGE_AFTER~ -->