Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am very sorry to hear about Kiki's behavior. Of course it is disconcerting and sometimes scary when affection is met with aggression.
In what context do the bites occur?
Or is it always if you've been petting for a while, even if it seems short to you?
Or is she stalking you and biting/pouncing on you?
Or is it in all of these situations?
What age was she taken from mom and her litter mates? 8 weeks is a perfect time to leave mom and litter mates. At that point mom should have taught her some social niceties and her littermates should have taught her not to bite so hard. I find that kittens taken from their mothers and litter mates too young are more aggressive and less confident cats and behavioral problems often result.
But even if she had good kitten soicalization if she's very energetic and you play rough with her she may be forgetting her manners.
So we need to teach her people aren't for mouthing or scratching ever.
Start by no longer using your hands (or any body part such as feet) to play with her.
Use toys, especially fishing line type toys or mechanical toys that he can chase, thus fulfilling her need to stalk and pounce, and that she can chase and burn some energy with.
If she does bite you yell "ouch" and then walk away and ignore her, play over.
If she continues to attack she's likely overstimulated. Use a towel to scoop her up and put her in a quiet "time out" room. Small bathrooms with dim lighting work quite well for this.
If she is a cat that likes to stalk you and jump out as you walk past then try setting her up a little.
Walk down a hall, let her start to chase but once she goes to pounce have an air horn ready and give it a blast. That isn't directly related to you, but it is to her actions. And if it happens every time she will get the idea this is no fun.
You can also use a squirt gun in face or the air in a can that you can spray in her face.
It does need to happen every time she misbehaves though or it will take longer to stop this behavior.
Never try and discipline with your hands. She is already overstimulated and she will just get more excited and bite harder.
This is a pretty common problem in very active cats, especially Siamese or oriental breeds and their mixes as they tend to very "oral" cats.
Do expect her to get a little worse before she gets better if her biting is related to play behavior as she is having great fun and won't want to give up her games.
Some cats get overstimulated by physical attention. And when this happens they will bite. They don't mean to hurt you, they are just saying "stop!" the best they can.
It is important to read the cues she gives before the bite to avoid it. It's likely his pupils will dilate (enlarge) or she will become tense or his skin will "crawl". It sounds like you have noticed some of these changes with her already. If you see or feel those warning signs start than stop and you won't get bit.
Some cats never get comfortable being held. They panic when they are picked up and lose control and respond by biting and scratching. Some do learn to tolerate it for short periods of time but I don't recommend forcing it as we are trying to build a positive trusting relationship between you and forcing her to be held when she hates it isn't likely to do that.
I would also keep your petting sessions very short with her.
She is fairly young but if she is an overweight kitty it is also possible that she has some spinal arthritis which makes petting pressure uncomfortable for her. If she seems to be hesitating jumping on things or less agile then before you might want to ask your veterinarian to take some radiographs of her spine to look for arthritis. If present then using glucosamine/chondroitin supplements like Dasuquin or Cosequin and an omega 3 fatty acid like 3 V caps or Derm Caps may be very helpful.
Let me know if you have any further questions.