This is what I found online:
Kitten bad breath is not a common problem for new kitten owners, but some people do find that their kittens breath smells bad. Not surprisingly, bad breath in cats and kittens can be caused by the same things that cause halitosis in humans - gum or dental problems, respiratory problems, or underlying disease. There are also a few things particular to cats that can cause an unpleasant odor on the breath.
Feline bad breath is often caused by tartar build up on the teeth. Just like in dogs and humans, tartar on the teeth fosters the growth of oral bacteria that produce volatile sulfur compounds, airborne molecules that smell very unpleasant. Although tartar has not generally had time to accumulate enough to cause kitten bad breath, you should check the condition of your kitten's teeth and gums to be sure there is no tartar or inflammation there. If you see signs of trouble, a trip to the vet is probably in order.
Respiratory problems can also be a cause of kitten bad breath. This is usually easy to pinpoint because it will be accompanied by signs of respiratory illness. Again, like humans and dogs, cats can get viral or bacterial infections of the nasal passages, throat and lungs. In turn these infections can encourage the growth of bacteria and may cause feline bad breath. If your cat has a respiratory infection accompanied by bad breath, the breath problem should resolve as soon as the cat recovers.
Another unusual cause of feline bad breath can be underlying illness - some metabolic disorders and organ problems such as kidney disease can cause an unusual odor on the breath. In most cases, the odor will not the typical sulfur smell of classic halitosis, but may still be quite unpleasant. A kitten bad breath problem that can't be attributed to any other common cause may be a sign that your kitten has a more serious problem that should immediately be assessed by a vet.
One cause of feline bad breath that is particular to cats is feline acne. If your cat has feline acne, you will see black specks or bumps on the cat's chin. These black spots are a buildup of secretions from the animal's glands, and the affected area can also be a site for the proliferation of colonizing bacteria. This unhealthy area can be the source of an unpleasant odor around the mouth, so part of your search for the cause of kitten bad breath should be an examination of your cat's chin. Feline acne can be treated with disinfectants: consult your vet for professional advice
So I would take your kitten to the vet, if only to rule out above causes, because bad breath is definitly Not normal.