Spark plug keeps going black on my aprilla sr50

SOURCE: no power getting to my spark plug lead

make sure threr is no blowed fuse make sure the connecters are snapped together look for any wires to be pushed out of the connecter if the plug wire is not made to the coil then the coli is bad

SOURCE: why wont my suzuki bandit 250 start?

If you tried to start the engine for any length of time, the plug would be damp and smell of petrol because fuel was being drawn into the combustion chamber. Without spark to ingnite the mixture, it would cause the plug to become damp. I am assuming you fitted the correct spark plug and that it is gapped correctly.

I don't mean this to sound foolish, but I would suggest you make certain the emergency kill switch has not been accidentally switched off. Also, if you have a sidestand safety interlock that prevents the engine being started while the side stand is down, flip up the sidestand and try again to start it.

Additionally, to make sure the plug wire is securely fitted to the plug. It is possible that the inside of the plug wire cap has gathered moisture and may need to be wiped dry.

If none of the above suggestions solve the problem, remove the plug then reconnect it to the plug wire and hold it near the cylinder - but not near the plug hole in the cylinder head (fuel vapors) - while pressing the starter . You should see an obvious spark. No spark likely means the coil is faulty.

SOURCE: KX125 BLOWING SPARKPLUGS ?

Hi mate i had the same problem in my kx85 the sprak plug blown then i put another one in and it went1st time what i done is used a BR9ES spark plug and i found the air screw to lean so i adjusted it to what it should be and it went a beauty it wont be anything to do with the electrics try this with yours get a BR9ES spark plug from halfords and see what the adjustement are in the manual mine said 1/38 turns out on the air screw also try and replace the cap that goes on the spark plug many thanks

SOURCE: 1986 yamaha big wheel 80

I believe the spark is too week, high tension sparks should be crisp fat and blue with a hint of orange, a weak spark could be the result of a faulty ignition generator or coil, sometimes the spark is controlled by a Capacitor, when these break down the spark will be out of 'Kilter' the Yeti... also check main and starting jets as well as any fuel diagrahms, good luck the YETI

SOURCE: yamaha trx850 bike stopped then restarted no

If they find nothing wrong then the problem is obviously intermittent and can be very hard to find. Check the operation of the ignition switch and all kill switches with a volt ohmmeter. Check the wiring harness. Did a wire come unplugged? Are all wires clean and with solid connections? Any abraded or pinched wires? Is the bike in neutral and the neutral light is lit up? If no neutral light, check the neutral switch and neutral wire connection.
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The usual source of intermittent loss of spark is the side stand kill switch. It kills the engine so that you don’t start out with the side stand down. Check for a broken wire at the switch or coupler. Get a service manual and check out the electrical section. Some bikes have a diode controller integrated into the turn signal relay. Try moving the kill switch by hand. If that doesn’t work then wire a jumper around the switch to bypass it. If that doesn’t work, check out the relay.The dealer would / should have load tested the various ignition components. I will assume the ignition system is okay. Check the battery and fuses. Install a new set of stock spark plugs.