Here is the moveset I recommend:
[email protected] berry
Ability: thick fat or sheer force
Role: physical sweeper with lots of HP and mediocre defence and sp. defence
Force Palm: good power plus STAB, chance to paralyze
Close Combat: Defense loss doesn't matter, Haryana already has low defence and sp. defence, high damage, STAB. Alternative is belly drum, which is good for killing everthing with bullet punch.
Reversal: takes advantage of hariyama's somewhat easily depleted health, deal INSANE damage when hariyama's has low health ,STAB. An alternative is bulk up, since it adds a boost to hariyama's fairly low defence, and amps up hariyama's awesome attack stat. Another alternative is bullet punch: it has priority and makes up for hariyama' low speed and gives a non-fighting move to use.
Earthquake/ heavy slam:deals with annoying poisons and ghost( non levitating ), high damage. Heavy slam puts hariyama's overly fat sumo body into good use: the heavier Hariyama is than a Pokemon, the more damage h. Slam does.
All attacks makes use of hariyama's awesome attack
Hoped this helped:)