Snapping or crack sound once per crank evolution
 

As the title says, there is a snapping or cracking sound, kind of like a pop, in the same spot once per revolution of the cranks. I hear it when turning the cranks by either crank arm or by either pedal. It's only heard when rotated forwards not backwards. The faster I spin the cranks, the softer the sound gets. The problem is with a Cannondale road bike with FSA Gossamer cranks and MegaExo BB.

I tightened the chainring bolts and the pedals. I took off the nds crank arm, greased the pinch bolts and reattached it. I would've pulled the drive side and removed the external BB cups and reinstalled them except that I couldn't find my bb wrench (probably is in storage).

I looked all over to see if something was hitting something else but couldn't find any parts making contact that would account for the noise.

Should I remove and reinstall the bb? Any other suggestions?

I'd pull the cranks and spin the bearings with my fingertips to check for any crunchiness. This could be debris or damage in one of the bearings. The Gossamer MegaExo bearings aren't very well sealed and tend to get crunchy easily, at least on CX bikes. On the family fleet I use a Raceface bearing press to pop the old ones out of the cups and replace them with Enduro bearings which have held up much better.

Try to relate the position of the crankarms to the sound. I once had a similar noise that was driving me crazy. It turned out to be the front derailleur cable rubbing the right crankarm.

When my bike did that, I found the retaining nut for the BB was loose. I torqued it to spec and the problem went away

The bb cups came loose with minimal pressure on the wrench, so I think the sound was from them being loose. The bearings were still very smooth, so I just cleaned and re-greased everything. The drive train sounds silky smooth now!

Thanks all for the help!

Rice Krispies in the BB? https://encrypted-tbn3.gstatic.com/i...YcpYY-2HcfLPAg