Knocking noises from crank area.

[foxychick]

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[NUKe]

Assuming its not a loose crank or bb bearing as you say you have checked those, 2 things to check
1freewheel/Hub pawls not engaging correctly .
Or
2 your pedalling action is going awry due to it being a different bike

[thirdcrank]

An age old problem. Keep an open mind - don't make assumptions about where it's coming from. What's the frequency? eg one a pedal revolution, once a passage of the chain, once a wheel revolution etc. Does only when pedalling imply applying pressure on the pedals or just when the pedals are turning? Does a different gear make a difference? Try the bike on a workstand, and if you haven't got one, try to suspend it somehow, even get somebody else to hold it up while you pedal. Turning it upside down isn't always much use, as the transmission will behave differently upside down.

[yostumpy]

I've had this, and it only occurred 'out of the saddle' at the end of the down stoke, both sides. Swapped the BB but it wasn't that , eventually tracked it down to 2 spokes in the front wheel, clicking, where they x over, so a loosen off and a rub with some emery cloth, the a re tighten sorted it, along with a speck of grease.