Motorcycle Without An Air...
 

...Filter? I recently purchased a 1997 Kawasaki Concours off of EBay. Shortly thereafter, I ordered a K&N permanent air filter in the mail. When I went to install it, I realized that the motorcycle did not have an existing air filter.The guy I bought it from rarely used the bike, and he did take it in to the mechanic prior to selling it. The mechanic cleaned and synced all four carbs, changed oil, etc.Both the seller and mechanic blame each other for the absence of the filter.My question is this:I have run the bike for about 1500 miles over the course of three weeks before realizing that there was no air filter. The bike seemed to begin to stutter a little in low RPMs, and I had to adjust the idle RPM because it would die periodically at stop lights.What is the possible damage to the engine? How can I identify it? What is the best course of action for dealing with this now aside from the obvious use of the K&N starting now and changing the oil?Thanks.

What is the possible damage to the engine? Worn pistons, piston rings, and cylinders. How can I identify it? Do a compression test.You're probably OK, but do a wet and dry compression test. If it's within specs, look into the intake, carb, and ignition as being possible sources of the inconsistent idle.

I know my Harley with a velocity stack will suck leaves and small dogs into the carb, no tellin what you hoovered into the engine.