Cyborg Kuro-chan was an anime series based on the manga series of the same name by Naoki Yokouchi that aired from 1999-2001. The series is about a cat who must look after his elderly parents but has to deal with the fact that he has been turned into a cyborg by a scientist.
The anime had a total of 66 episodes, 1-60 can be found online in Japanese as well as 65 but episodes 61-64 cannot be found online in Japanese.
Episode 61 (Muscular Beauty-Large Battle!?) originally aired on November 25th 2000 and is about a fitness competition that Kuro and his friends attend. In the episode Grandma, Megumi and Nana take part in the competition and they try to complete various challenges in hopes of winning a prize. Kuro steps in to help stop 2 bad guys who are trying to distract one of the competitors.
Episode 62 (Gift Strategy of Suzuki) aired on December 2nd 2000 and is about Suzuki trying to find a gift for Megumi. Kotaro and Suzuki find an object in Dr Go's home which they use to make a necklace for her, but there's trouble when Go and Mi find out that the necklace can freeze things.
Episode 63 (Scrap King Appearance) aired on December 9th 2000 and is about Mi being swept into the sea and Go and Kotaro's quest to try and find him. They later find out that the rubbish dump near their home has transformed into a giant monster.
Episode 64 (Courier From Space) aired on December 16th 2000 and is about a mysterious item that turns up at Kuro's home and he and his friends must find out what it is.
These 4 episodes are impossible to find in it's original format online, only the Russian, Thai, Mandarin, Cantonese and Arabic versions exist, episodes 63 and 64 also exist in Vietnamese.These are the only versions of the episodes that have surfaced on the internet. The episodes haven't aired on Japanese TV in over a decade and it is possible that nobody taped them or that they were taped and the tapes became corrupted over time.
The series was eventually released on Amazon Prime in Japan including these 4 episodes. YouTube user and Kuro-chan Enthusiast DavoDoss has TV recordings of the episodes from their broadcasts on AT-X in Japan.