Does Your Scooter Ping?

Steverino · 10-05-2005, 07:14 AM

Ad if it does will running a higher octane fuel stop it?

Bueller · 10-05-2005, 07:31 AM

You are a funny dude.

2T scooters will ping from excess carbon build-up, too much ignition timing, too little octane, or from being jetted too lean. Any other questions?

Steverino · 10-05-2005, 07:32 AM

Quote:

Originally Posted by Bueller

You are a funny dude.

2T scooters will ping from excess carbon build-up, too much ignition timing, too little octane, or from being jetted too lean. Any other questions?

Will increasing the octane rating decrease the incidence of pinging?

Bueller · 10-05-2005, 08:51 AM

Quote:

Originally Posted by Steverino

Will increasing the octane rating decrease the incidence of pinging?

That depends on the cause. Pinging can be caused by several factors, so to answer your question you must know the cause of the ping. If the ping is coming from compression-induced spontaneous ignition, higher octane fuel will help. If it is caused by another ignition source (such as a hot spot or carbon build-up) higher octane will probably not help.

Compression-induced pinging can be caused by too much compression for a particular octane rating, or by having the timing too far advanced. The first one is easy to understand, but the timing issue gets a little more complex. In the case of over-advanced ignition timing here is what happens. The piston is still approaching top dead center, compression is heating the mixture. If the spark plug lights it off too early the additional increase in pressure from the burn combined with the fact that the piston is still rising will cause whatever portion of the mixture that is not yet burning to spontaneously detonate. The noise you hear is caused by the two flame fronts meeting. If left unchecked it can do massive damage.

Higher octane will fix pinging caused by higher static compression. But it will only fix the symptom of pinging in the case of over-advanced ignition timing, and even if higher octane gets rid of the pinging you are still going to have to deal with the extra heat generated by the advanced timing, something that has been known to cause seizure in 2t engines. A better solution would be to properly dial in the timing.

Any other questions?

How 'bout a tall glass of koolaid?

Photog · 10-05-2005, 09:03 AM

Um

Uh, Steverino, mine pings because I'm a dumbass about this kind of stuff.

Jeebus, it's got 4 moving parts in the motor (literally) and it's still over my head.

ilmostro · 10-05-2005, 01:53 PM

No.

Rad · 10-05-2005, 01:54 PM