QuestionQUESTION: bike starts and idles,but try to roll on throttle it quits,new plugs,gas,cleaned carb, carb is a cv( exact )? it it a chinese knockoff bike ,cant find any info on bike,only has 350 miles on it,any help ?????
ANSWER: Chinese knockoffs are not exactly known for good quality and proper design. But before I can help you, I need more info... what size is the motor and what is it a copy of? Have you done any checks on the ignition system?
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QUESTION: size is a 250,knock of a yamaha, good spark,gas,air cleaner, could it be the advance in ignition if it has one?
AnswerChances are an '03 Chinese knockoff will have an electronic ignition. I found a photo of a Defiant online, it looks like a 250 Virago. You could try purchasing a repair manual for the Yamaha version and use it as a guide to help you with yours, but it's no guarantee that Yamaha parts will fit. Here's an online site where you can buy one:
http://www.repairmanual.com/motorcycles/2003/69/0/9918
As I've never even seen a Defiant other than in a photograph, I really won't be of much help to you other than to suggest try replacing ignition components until the problem is solved. As you've said there is good spark, that pretty much eliminates the plugs, wires, coil and CDI unit as the source of the problem. So, if you can locate the ignition pickup plate it should have slots under the mounting screws that will allow you to rotate the unit. You can try moving the plate to different positions (mark the start point first) to see if the performance improves. You will need a timing light to do this properly.
You could also try asking your question on the tech section of the Virago Owners Club, perhaps someone with a 250 can give you some advice on what/how to do it:
http://www.viragoownersclub.org/
