I own a cbr600 f3 1998, can anyone tell me why it pops going Down hill in a low gear

 

Overrun. Typically its not a bad thing. It is caused by lean conditions when you roll off the throttle but the momentum (or gravity) keeps the bike moving. I found it more pronounced after putting a slipon on (less backpressure, yadi yah). Try sinking your carbs, might help.

 

Thanks c/f does this mean I will have to have the carbs balanced. This all happened when I put a K&N air filter, it seems to run lumpy on low speeds, but goes like hell when I am gunning it.

 

Never hurts to check the balance, but in all likelihood it is a lean condition. Those K&N filters are a higher flow medium than oem. More air = leaner running. You may want to enrich your mixture a bit, that should take care of the bogging at low rpm and the popping on overrun.

 

Thanks c/f for your help. I think I will try the old ome filter to see how it runs. Thank you once again, all the very best, Jeff