I couple of weeks ago my son's DR50 wouldn't fire at the plug. We checked connections, switched plugs...still no good, then just fired away like there wasn't ever a problem. I put a new piston & ring set in last weekend and haven't gotten a spark since. I'm not sure where to start and really need some help with this before my son sends me to the looney bin because he wants to ride! Of course, I'm trying to limit the money I put into it because of what I've already replaced a brake lever, silencer, air filter, piston kit and shields. Help!!
Assuming you absolutely have no spark, and there isn't something else. You probably need a new coil. That little box that the spark plug wire goes to. You have to buy the whole thing, plug wire and coil since they're one piece. I had to replace one just the other day for that very reason. Just wondering, are you using the stock carb? If so it will give you troubles, and seem like you're not getting a spark. Take the spark plug out, connect it to the plug wire, and have someone kick start the motor while you hold the plug next to the engine head. About a 1/4 inch away from the head. See if it sparks. A darkened area may help. Don't touch the plug! OUCH! Just the plug wire.