If you are running stock air cleaner or any air cleaner set up that routes the head breathers back into the CARB/FI throat than you are going to get some carbon build up from the oil vapor. Carbon can cause pinging in just about any motor.
Take a spray bottle and after bike is warmed up hold throttle at about 1500-2000 rpm and start spraying directly into the carb throat and don't let engine die. Keep spraying about 4 ounces or so in the harley engine and the carbon will be blown out the exhaust.
Try to direct the spray down the center of the intake and avoid any sensors or you may set a code that has to be cleared.

It's best to do this before an oil change so any water vapor that may get into the oil will be removed during the change.

Most engines will respond very favorably to this treatment.

Don't want to screw this one up. Are we talking spray bottle of water??

Yes, the pump type or the squeeze type will work fine.

I've looked around on the forums but have found no info on head breathers back into the carb. Is it worth while to reroute these so the exhaust isn't entered back into the carb. but to an external catch or filter and if so what is the best system?

I've got a question relating to this issue, G. Recently I replaced the enrichener cable and when I took the breather tube off there was an oily watery slobber inside the tube. is this just condensation from riding in the cold or something I should worry about or just situation normal? I rinsed it out in the solvent tank and blew it out with the air hose before I put it back on.

I've looked around on the forums but have found no info on head breathers back into the carb. Is it worth while to reroute these so the exhaust isn't entered back into the carb. but to an external catch or filter and if so what is the best system?

Some reroute them but most don't. There are many catch cans available but everyones preference is different as far as looks and mounting positions.

I've got a question relating to this issue, G. Recently I replaced the enrichener cable and when I took the breather tube off there was an oily watery slobber inside the tube. is this just condensation from riding in the cold or something I should worry about or just situation normal? I rinsed it out in the solvent tank and blew it out with the air hose before I put it back on.

Normal for that to be in the tubes. It's oil mist and condensation.

I've done this to car engines before it works very well no one would ever think of it. To tell you the truth I was skeptical at first but it really works.:D

Have you ever seen if you park the tail pipes close to a wall what comes out? You may be surprised. You'll have some big black spots there after you're done.

Have you ever seen if you park the tail pipes close to a wall what comes out? You may be surprised. You'll have some big black spots there after you're done.

Never witnessed that happen but I suppose it could. I've decarbonized the blades in a turbocharger on my old car using your method. It does cloud things up pretty well so I guess pull it away from the wall before starting or you will have a mess.:s

If you have ever pulled a cyl. head off an engine with a blown head gasket you will find that piston will be nice and clean fron the steam cleaning that it got from the coolant that got into that cylinder.

Yeah I've seen that but sadly the engine had been ruined by it.