KITERETSU ENCYCLOPEDIA

The main character is a scientific genius boy named Kiteretsu, who has built a companion robot named Korosuke. He frequently travels in time with his friends and Korosuke in the time machine he built. Miyoko is a girl in his neighborhood who is basically his girlfriend. Tongari is his rival, who happen to share some similar traits of Honekawa Suneo. Buta Gorilla (Kumada Kaoru) is a typical neighborhood bully, who also share similar traits of Gian (Takeshi Goda) except that he often antagonizes Korosuke (though they are in grade school). (Source: Wikipedia) — Description from AniList community (anilist.co).