Well over 90% of running issues with newly purchased Rebels are carb related because they usually sat with gas in the carbs. Review this thread and do the other stuff (adjust valves, check tank for rust, air tires, etc.,) it suggests. If that doesn't fix the problem, I would focus on the carb. Lots of info on carb cleaning here. Basically, there are two options for carb cleaning; disassemble and run the carb through an ultrasonic cleaner or soak it in Berryman Chem Dip. Because the carb is usually gummed up to varying degrees, suggest you soak only the metal parts (Chem dip destroys plastic and rubber) for a week before rinsing thoroughly with water and blowing out every orifice with high pressure compressed air. To soak it for less time increases the chance it won't get clean, and you'll have to remove it and repeat the process until it is. If you have any questions, feel free to ask. The only stupid question is the one you didn't ask.
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