I have a 1978 ke 125 i got for 20.00 at an auction. I have it together, and it runs good, but my carb isn´t to my satisfaction. I´m not very good a carb adjustments. Just the basics. It idles good, but when i goose it, it hesitates and slowly accelerates. When it reaches about 2000 rpm. Then it takes off. Down shifting up a hill, it will just die, and takin off, I have to have the rpm high. What do I check? What do I adjust?