How do say “can you ride a motorbike” in Tagalog?
Also how would you ask somebody if they know how to do something. For example very “do you know how to cook adobo?”

Question

Answer

Can you ride a motorbike? - marunong ka magmotor/magsingle? or marunong ka mag-drive ng motor(ng single)?

do you know how to.. 
= marunong ka mag...? (informal)
= marunong ka po/marunong po kayo.. (polite. the second one can be used to one person or to a group of people)

Answer

The other answer, by Jose, is actually the correct one.

Answer

Can you ride a motorbike?
- Marunong ka bang mag-motor?
- Marunong ka bang magmaneho ng motorsiklo?

Do you know how to cook adobo?
- Marunong ka bang magluto ng adobo?

In general:
Do you know how to...?
- Marunong ka bang mag[+verb/pandiwa]
Ex. verb/pandiwa = dance/sayaw
Do you know how to dance?
- Marunong ka bang magsayaw?

For polite way change the phrase "ka bang" to "po ba kayong"
Ex. Marunong po ba kayong magsayaw?