what are some of the symptoms of running too lean ?

 

The engine will normally misfire when the amount of fuel is too low relative air supply. A lean mixture is harder to ignite, therefore misfire will occur at some point. You would also check that the plugs have the right colour if you suspect lean mixture.

On a modern engine with a high energy ignition system, it is almost impossible to detect a lean condition by misfires. But on the CBR which works with only +12 Volt coil supply I'm quite convinced misfiring will occure at a lean condition. However, you should still always monitor the plugs after doing any changes such as putting in a better flowing air filter or exhaust system.

You will also loose power if the air/fuel ratio lean, e.g. 14 to 1 instead of 12,5 to 1, but any minor changes in power is hard to recognise in the pants. The only reliable way to measure power changes that I'm aware of, if you don't have access to a dyno, is to check changes in top speed. E.g 10 % power loss will ruffly give 3 % in top speed reduction. To register such small changes one almost needs a GPS receiver with memory for top speed, and top speed blasts shall only be done where it is completly safe.

 

yes... never on an empty straight road 50km from any town where you can't see any other living creature to the horizon...

 

We are all reasonable people here, and I am sure that none of us would ever dream of such a thing.