Another reason could be that Kakashi underestimates Naruto's potential. He might think that Naruto is not ready for more advanced training yet. He could be misjudging Naruto based on his initial performance or his rowdy behavior. However, this would be a big mistake as Naruto has a lot of hidden potential waiting to be unleashed.
It could be that Kakashi has some personal issues. He has his own demons from his past, like the loss of his father and comrades. These emotional burdens might be affecting his ability to focus on Naruto's training. He might be in a state of self - reflection and not be in the right mental space to be a good trainer at the moment.
Maybe Kakashi is preoccupied with other important missions. He is a highly - skilled and often - needed ninja. There could be some top - secret missions that require his full attention, leaving him no time to train Naruto properly.
In the fanfic, Kakashi might neglect Naruto's training due to a variety of reasons. He could be preoccupied with his own research or a secret mission that demands his full attention. There could also be a misunderstanding between him and Naruto. Maybe Naruto has done something that Kakashi misinterprets, causing him to distance himself from Naruto's training. Additionally, the fanfic could introduce new characters or plot elements that draw Kakashi's focus away from Naruto. For example, a new threat to the village that Kakashi feels he must handle alone, thus neglecting his duties as Naruto's trainer.
One possible reason could be that Kakashi might think Naruto is not ready yet. Maybe Naruto hasn't mastered some basic skills that are prerequisites for the more advanced training Kakashi has in mind. Another reason could be that Kakashi is worried about Naruto's recklessness. Naruto has a tendency to rush into things without thinking, and Kakashi might fear that this could lead to Naruto getting seriously injured during the training.
Naruto might also try to find alternative ways to gain strength. He could explore the forest around the village to find new training areas or discover new chakra - related phenomena. He has a curious nature, and this could lead him to stumble upon something that gives him an edge in his training, like a hidden hot spring that has special chakra - enhancing properties.
One reason could be that he saw Naruto's potential later on and realized he could have been much stronger if he had trained him earlier. For example, Naruto has a great deal of chakra and tenacity, and with proper training from Kakashi earlier, he might have reached new heights faster.
Another reason could be that in this fanfiction, the plot is set in a way that there is a new training system in the village. And this system doesn't involve Kakashi in Naruto's training. There could be new mentors or a completely different approach to training young ninjas like Naruto, which excludes Kakashi from the equation.
Perhaps he's been influenced by someone who gives him bad advice. For example, if someone tells him that natural talent is enough and training is overrated. Also, he could be dealing with some personal problems, like a conflict within his family or among his friends that takes up all his time and mental energy, causing him to neglect training.
In the fanfiction, Kakashi might train Naruto in teamwork. Even though Naruto is often a solo fighter, Kakashi could show him the importance of working with others. He could arrange mock battles where Naruto has to team up with other characters, like Sakura or Shikamaru, and learn how to coordinate their attacks and defenses.
In many Naruto fanfictions about Kakashi training Naruto, Kakashi might push Naruto to new limits. He could focus on Naruto's Rasengan training, making it more powerful or teaching him new variations. For example, Kakashi might introduce elements to the Rasengan, like wind or lightning, to enhance its destructive power. This kind of training would not only strengthen Naruto physically but also help him understand chakra better.
It could also have caused a rift between her and Kakashi. Sakura might start to resent him for not believing in her or giving her the proper training. This could affect the team dynamic. Maybe she would start to distance herself from the team and try to find her own path, which could lead to some interesting plot developments in the fanfiction. For instance, she could end up joining a different ninja squad temporarily to get the training she needs.
In this fanfiction, Kakashi could help Naruto in his training through mental conditioning as well. Naruto is often impulsive, so Kakashi may work on his patience and decision - making skills. He could use his Sharingan (if applicable in the fanfiction) to analyze Naruto's movements during training and give him detailed feedback. Moreover, Kakashi could introduce Naruto to different types of enemies and battle scenarios in a controlled training environment, which would broaden Naruto's understanding of combat and make him a more versatile ninja.