The 'Bomba' section or 'Mazacote' or 'breakdown' in Timba can be played numerous ways depending on the arrangement.
By 'Bomba' it is not the actual "bomba" folkloric pattern of Puerto Rico, in Cuban Salsa/Timba context it refers to the modern style of Cuban Timba/Salsa breakdown moment with the going of the ride cymbal/broken beat pattern of the cencerro and use of the kick drum with the sliding notes of the bass with the displaced montuno's of the piano typically with looped short horn section 'mambo' or short horn riffs looped, followed in with heavier type chorus etc...
If no formal instruction can be found close to you, listen to the congueros in modern Cuban Timba bands the likes of Charanga Habanera/Charanga Forever, Manolito y Su Trabuco, Bamboleo, Aces de la Timba, Klimax, Azucar Negra, Chispa Y Sus Acomplises, Manolin (Medico de la Salsa ) - but his Timba recordings not the pop stuff.
Its hard to explain over internet, here is a little short clip of young Dominic (friend and casual student of mine) jamming over a recording of Cuban Timba band 'Bamboleo', you can see and here him play variations of this "bomba" / "mazacote" / "breakdown" section on Tumbadoras/Congas. It is derived from Songo/Changui and modern cuban style marcha/tumbao.
http://youtube.com/watch?v=QYteuQOjohUAnd here Dom again but on Cuban Timba style Timbal/Drumkit set up playing a timba/breakdown groove:
http://youtube.com/watch?v=m2KOgHbsSms and
http://youtube.com/watch?v=5uSVLsxdZZEMore on this style can be seen here, with my bro Steve here on drums/timbal:
http://youtube.com/watch?v=mVp_y6l81eIhttp://youtube.com/watch?v=gPlekAZ_MsMAnd here Jimmy Branly (formerly NG La Banda)
http://youtube.com/watch?v=F_34oDF6ZIsHope this has helped.