Ping And Detonation

[flyin64]

i read this oilder post and had a question- i am using 93 grade fuel and notice it under load when accelerating. when i back off the throttle it goes away. what can i do to eliminate it? i did not pick up a solution in the older posts.

i ride an 98 fxdl-

cheers mates

 

[TripleJ]

If you click on the link Mr. Data provided in the original post Detonation and Pre-Ignition you will find the title listed below that would be agreat place to start.

A DOZEN WAYS TO PREVENT DETONATION

Good luck and let us know if any of that works for you.

 

[Jack Klarich]

i read this oilder post and had a question- i am using 93 grade fuel and notice it under load when accelerating. when i back off the throttle it goes away. what can i do to eliminate it? i did not pick up a solution in the older posts.

i ride an 98 fxdl-

cheers mates

How many miles, are you lugging the engine? You may have a lot of carbon built up on top of the pistons causing hot spots across the top, may try a better gas station first JMO

 

[wilks3]

Try running some SeaFoam in 2 or 3 tanks of fuel. Use the per oz ratio. This stuff works!!
If it can be chemically cleaned, SeaFoam will work.
Ride Safe
wilks3

 

[BUBBIE]

If you have a lot of Carbon build up or suspect that,,,,,Take off-out the air filter, while at a fast Idle, warmed motor, take a spritzer bottle of water... CAREFULLY using the FINE spray into the venture and keep the motor running fast,,,,, That should get out the built up carbon in the cyl and piston tops...

I'm not saying to squirt water in any UN controlled amount ,into the engine BUT only using a fine misty spray..
Too Much liquid of any kind in a cylinder can cause a compression problem, Bending/Breaking the rod or crank..

Liquid does NOT compress smaller in size.... so careful

If you have ever had a water (head gasket) leak in a gas water cooled motor,,,,,When you replaced the gasket and it apart, You will notice NO carbon build up in that cyl. IF run with the leak into that cyl for a while...

signed....BUBBIE

 

[LARK]

Just for a little clarification, pre-ignition and detonation are really two different things. Pre-ignition is when the fuel/air mixture in the cylinder ignites before the spark plug fires. Usually caused by high combustion chamber temperatures and a hot spot in the chamber. Carbon, thin valve edges, rough casting flash all could be the source of pre-ignition. This normally happens in engines that run under a load for an extended period of time. Small air cooled aircraft piston engines are one example.
Detonation is the rapid uncontrolled burning of the fuel/air mixture when the plug fires. The ping we occasionally hear is a very, very mild form. More annoying than anything else. That why Harley says don't worry about. The knock sensor will hear it and pull timing. With harmful detonation you don't hear a ping, you feel it with a shutter or stutter. When that happens ugly stuff is going on to the top of your pistons.