Puzzling noise ?

Hello folks, I asked some tuning questions on this forum a while ago, but cannot find them now. However to recap, I have a 2009 Bonneville SE and have done some mods recently. I have removed the o2 sensors , AI injectors , removed the snorkel , fitted Dyna filter and done the tune. The bike runs perfectly, and the spark plugs are a perfect colour. However there is an odd noise which I can only describe as a " click " when the engine is running , its about every 3 seconds , that doesn't change as the revs rise. Any thoughts of what this could be ?

 

No I left it in place. I watched a " delboys garage how to video " on Youtube, he left it on , so I did too ! I guess thats where the noise is coming from then, thanks for the answer.