When people complain about their bike pinging, is it prevelant during acceleration or cruise or does it matter? Or is it only a ping during acceleration and its something else when you cruising high speeds? Whats everyones take?

 

Read this: http://en.wikipedia.org/wiki/Engine_knocking

 

The set of conditions most likely to creating pinging or detonation are: hot engine, overly but not extremely lean mixture, low octane fuel, wide open throttle, high engine load (such as uphill in 6th with a couple fat people on the back).

This is when both heat and chamber pressures are at their maximum, which is what causes pre-ignition.

 

Usually it's most obvious when you're "lugging" it, such as cruising in top gear at low RPM (2200 or so) and then rolling on the throttle without downshifting. Uphill and/ or heavy load like OJ described definitely exacerbates it. But it can occur even at constant cruise speeds. The factory tune is pretty lean for emissions purposes so stock bikes will ping sometimes even with 93 octane. A good tune will richen it up and stop the pinging.

 

Pinging is typically most prevalent under a load, such as that encountered during acceleration, or cruising at a steady speed on an uphill grade, although there are several factors to consider.

If you go back to the old days before electronic controls, timing advance was directly proportional to engine RPM. As engine RPM increased so would the timing advance. Additionally, when you added a vacuum advance into the system then throttle position, and therefore load, played a role also. At lesser throttle openings (less load, higher manifold vacuum) the vacuum advance would advance the timing even more. At WOT where manifold vacuum is at its lowest the vacuum advance would not have any effect. The primary purpose of the vacuum advance was to provide for additional timing advance under lower load cruise conditions to improve fuel economy. The mechanical advance and the vacuum advance where directly proportional to the engine's immediate environment.

In todays electronic systems the timing advance is programmed in to set values at various environments, i.e, RPM, throttle position or MAP (manifold absolute pressure). Therefore, dependent on the way the system is programmed has a lot to do with where the pinging is most likely to occur.

Obviously the engineers doing the programming would have followed curves similar to those provided by the mechanical systems described above, although they do have more flexibility to tweak the programming at certain points that could not be done with the mechanical systems.

So to answer the original question, where is pinging most likely to occur? It's really dependent on the timing curve the engineers have programmed in and any subsequent changes that may have been made by an aftermarket tune, although generally speaking it is most likely under higher load environments.

 

Reason I ask is at 75-85MPH maintained I will not get the chatter noise like a multiple valve concerto but one or so single momemtary note. Tried floring the throttle to see if I would get a load chatter (none) just that very subtle almost undetectable noise. Thought I would go to a cooler VRod plug and run some Seafoam thru it. Not convinced it is a pinging issue?

 

When I put my headlight nacelle back together after installing my apes I noticed the outter ring that attaches with a spring clip at the top and a single screw at the bottom is not real tight. It actually could vibrate at higher RPMs and wind buffeting to possibly give a chatter noise like I discribed in last post. I need to fasten it tighter before I can rule out any noise input if any Imay be getting from it?

 

First, you have to be able to tell if the sounds you're hearing are pinging or something else. To the experienced ear this is not very hard to do but to those less experienced it can be more difficult.

The "single momentary note" you describe may well be the ping. Kind of a "tink, or tink-tink" sound. If that is the case, what you are hearing is the initial ping and then the subsequent elimination of the ping by the knock sensing system retarding the timing.

If you're not convinced that the sound you are hearing is a ping, then I'd suggest getting someone with a little more experience to check it out.

When my bike was new and I mentioned it to the service manager at my local dealership, he told me "they pretty much all do it and not to worry about it. It'll go a hundred thousand miles like that." That discussion blew any credibility they might have had in my eyes and I proceeded to do my own tuning to eliminate the ping I was experiencing.

 

You're mixing detonation and pre-ignition, and the fact is that they're very different phenomena. Rather than handing out your opinion as fact, why not educate yourself?

 

Heard this twice. First time it was driving me nuts, new plugs, other goodies did not aleviate. Found out it was a harmonic vibration in 4th/5th @ 2000+RPM picked up by the custom fuel cap. Few adjustments to cap & noise was gone.

Second time after PCV tuning it was actually a ping or more like an exaggerated rattling...had it only at 65+/6th while steady cruizing and usually not under power. Seat-o-the-pants dyno allowed me to tweak the map to work most of it out.