49cc no spark
What make, model, year is the bike??? The coil likely has no gap to set. Do you have a points type ignition system?? The spark plug and any other gap(s) will always be critical so do not rely on a bit of business card or other thing unless you know it is of the correct or close to the correct thickness to achieve the proper gap. With points if the gap is to large the dwell will not be sufficient to allow an adequate voltage rise and if the spark plug gap is too small it will allow a weak spark to jump too soon and if it is too large the spark may never reach a high enough voltage to bridge the gap. It could be so weak, so low voltage that it will not bridge a spark plug gap or you will not see it or otherwise evidence it because it is so weak. If there is spark but weak and the bike will not fire this is exacerbated with increasing compression pressure as it will be harder for the spark plug to fire/spark as required with increased pressure. With some bikes if you have both of two spark plugs disconnected ie wires not grounded at the plug end there will be no spark produced. That is another reason why bike information is needed to properly address your question. Also one would like to know how you are testing for spark? You also should provide some history of the problem and why you have done whatever you have done so far?
Aug 17, 2014 |