So heres the story...... I last started my bike about 3 weeks ago. When I did this I needed to use a jump start box but it ran fine after that. Toay I went to start it again and to no surprise I needed to use the jumper box again. Problem is that once it was started it didn't sound like it was running right. So after running it again and doing a little investigative work I found out that one of my pipes was hot, the other was cold.... I took out the spark plugs and sure enough the one of them was just wet and didn't appear to be firing. I switched the plugs to see if it was a plug issue and it seems like the plug works ok because the same cylinder was working as before. What else could this be?? Im not that mechanicly inclined so if its something obvious ill applogize in advance!

 

Don't apologize. The only dumb question is the one that goes unasked.

Here is the problem I had which sounds alot like yours. Mine ended up beingthe rear jugs spark wire was pulled ever so slightly out of the coil. And while the boot was all the way inserted the wire was a little back on the boot. So here is my suggestion. Pull the boot back on the spark plug wire at the coil. Insert the cable all the way into the coil, then push the boot forward. Do this for the other end of the wire as well, making sure you dont pull it off the coil when doing so. The use of dielectric grease on both of these connections is recommended. If that doesn't do the trick, you might want to check your plugs, coil and ignition. There is also a connection that runs down the front of your bike from the voltage regulator that has a dutch connector located back by the kick stand.. this plug gets fouled even though its a sealed connection. Clean that out and dielectric grease that too.

Hope that helps.

 

The piston that isn't running isn't getting fire. You eliminated the plug as the problem. I'd say the above advice is good to follow. Check the wire connections from the coil to the plugs. Then the volt reg. If all of those connections are good, the problem is probably the coil. Seems we've read several of those going bad lately.

If you are not gonna start the bike for 3 weeks or so at a time, I suggest a battery tender. That isn't the cause of THIS problem, but it will serve you well in the future.

 

You can get a schumacher battery charger that is both 6 and 12v at wally world it goes to float when the battery is charged. It is only $17.44 and is well worth it. I use is on my lawn tractor, cars, etc. Harleys use a wasted spark ignition and have since something like 1927, both plugs fire at the same time. The cylinder that is on the exhaust stroke is "wasted" and hence the name. So I would look toward the spark plugwiring. I would think if it is the coil it would not run at all. You didn't say what year it is or if it has been modified. Look around, charge battery before doing anythingelse. Fuel injected engines do not like low battery voltage, if it is one of the new ones.

 

switched plug and seems OK ?[sm=WTFsgign.gif]
fouled plugs suck
Go get yourself a NEW set,then go from there.
and if in doubt stick finger in plugboot and start her up andsee what happens and Please let us know[sm=yikesomg.gif]

 

What he said.

The "boots" may be very stiff but they are not part/attached to the wire, just stiff to keep out moisture. A boot too low could keep the wire from snaping onto the end of the plug.
Coils can go bad at any time. If all your wires & connections are secure you may want to get somebody with a multimeter to check things out.
A battery tender or charger does not extend the life of plugs or coils, just the battery. It will not solve your problem.
A manual can help you find the various connections, plugs, coil, battery. It won't solve the problem if it is a bad coil, but it is a good thing to read and get you more familiar with your machine.
Dielectric grease can be bought at any auto parts store. It is also a good thing to have for directional bulb and headlight connections. It helps to keep out moisture & corrosion

 

First make sure you have a good charged battery, the ignition module might be acting funky from low voltage. Also confirm proper running voltage with a multimeter, you should read something around 14 volts. Have you checked to see if there is in fact no spark at all. Take both plugs out connect the spark plug wire to them like normal, and just let them rest on the engine, and hit the starter, and you can watch to see if there's any spark. If no spark at all is on one plug, then it is either the plug wire or coil. Stock coils on all sporty's to my knowlege are single fire so both plugs fire together at all times. If you do see spark on both plugs, then most likely it's an issue with the ignition module.......but like I said before, make sure you have a good charged battery on the bike and check what the running voltage is to insure theres not an issue caused by low voltage.

 

Take a spare plug , attach it to that plug wire, lay it on the head and crank the engine over and look for spark.Make sure you leave the plug in the suspect cyl. (to prevent a blowup) No spark, backtrack #1 plug wire, #2 coil (check input voltage) #3 no juice to coil ,check igniter box. Always go from the end towards the source,and check all grounds in that circuit.

 

Charging the battery is good, the spare plug test for spark is good. But, know this..I did all that and even replaced my coil and ignition and it ended up being the problem described above. Since then I have solved this very problem several times on other bikes with the same procedure. Check it all though, better safe than sorry.. Getting stranded sux.

 

I would indeed be sure that the plug wires are connected as lonerider suggests but, I would be more inclined to think that your battery is causing the problem. Clean or, replace the plug. Fully charge the battery or, replace it.Just because you were able to charge the battery to get it started does not mean that it is fully charged. You may not have run it long enough to 1) burn off the fuel in the cylinder and on the plug, 2) fully charge the battery off of the alternator.
Good luck.