Several times now I have experienced a moderate ride of 150 miles or so whereas the 1st half of the ride the bike runs perfectly and then, for no apparent reason, even on the same tank of fuel, it starts pinging. This ride took me from 850' el. to the coast, then up a mountain highway of moderate elevation maybe tops at 3,000', then down and back on flat highway back home. After a fairly aggressive ride down the mountain, with moderate decel popping on high RPM engine breaking, I get back on the interstate and cruising at a flat 70-75 (RPM 2800-3000) I get pinging on even the slightest throttle increase. It's literally like being on 2 different bikes.

I'm running a PCV from Fuel Moto, K & N Intake, V & H Headers and Rinehart Slip-ons. I've tried various maps, none of which howver alter the timing, but why would it run fine for 70 or 80 miles and then like crap for the rest of the ride?

Any thoughts or suggestions greatly appreciated.

Dan

 

Are you riding in different areas of the fuel map? Sounds like highway riding with stops followed by interstate riding. Anyway do you know if you have your Accelerator pump enabled on you Power Commander? I run the accelerator pump option which "squirts" a little extra fuel with the twist of the throttle. % throttle change drives the function and % change and engine revolutions are the variables.

 

so pinging is pre-ignition of the fuel- the fuel burns at a rate uncontrolled/ imcomplete/ faster than desired ( due to problems with the mixture- usually too lean) or ignites before that desired time- like when the piston is down the bore coming up- and the expanding gasses try the push the piston back down reverse direction, rather than over the top and down a forward motion.
Ignition timing is generally advanced so that the spark plug starts the burn 3000 milliseconds before the piston reaches TDC, so that as the piston hits TDC the expanding gasses push it down and froward. ( this is why the spark fires earlier, the faster the piston speed/ RPM.) decreasing timing advance from ideal settings will reduce power potential and fuel economy


pinging is influenced by mixture as we know, ignition timing and by temperatures in the combustion chamber.*

it is possible that as your motor heats up that the ECM / tuner etc. is not compensating for the increased temps in the combustion chamber.

first thing I would try is pull over and stop. turn off the bike and restart it to see if the ECM/Tuner "reset" or make any positive change.

if not then look at the settings in the tuner.


Mike

* any sharp edges in the combustion chamber can heat up and glow like a plug, causing pinging- and pinging can further burn aluminium, causing more sharp edges...persistent pinging will destroy a motor.

 

Many variables. Even the slightest of grades, or headwinds, or temperature change, etc. can cause what you're describing. Your best course of action in my opinion is to back out a little timing in the problem areas until you eliminate the ping.

I had similar issues. If you want I can share my timing map with you, but I'll have to do that later as I'm running short of time right now.

 

My 07 SG w/ a PCIII has the same basic issues. No amount of dyno tuning, fuel table mods & ignition adjustments has eliminated it. I finally settled on removing 1-2 degs of timing in the 2800-3500 rpm ranges to get it close enough. I still get some pinging noise but its far less than before.

 

Hey guys, thanks for all of the replies so far. I am at work so I can't completety digest all of the info you've all given but I will take some time this evening to further assess and maybe add some comments.

 

I might also check to make sure all the intake air connections are tight...if as it gets hot over time the parts expand and open a slight gap letting extra air in the intake could cause pinging...and then when the engine cools the gap closes back up....anyway, its worth a look....also check for cracks in the throttle body and intake....

 

.."accelerator pump" feature on the PCV does nothing for slow revving V-Twins, (except waste gas). The best position on that is "off". It is only useful for high revving sport bikes..it doesn't shoot a burst of gas in on a fuel injected bike... sounds to me like your issue is related to heat....

 

heat,07 hear same thing. good tune helps but if it gets hot enough the ping returns.looking at wards fan kit but holding off for now,going to lower gearing this winter see if showin the motor less load helps with heat and ping.

 

I have a suspicion that the culprit may be a leak in the exhaust somewhere. The problem didn't manifest itself until last year when a cracked "Y" pipe caused me to replace the stock headers. That's when the V&H True Duals went in and I just put the Rinehart slip-ons, which were on the stock headers, back on the new ones. I immediately started to notice alot of decel pop and then shortly after the pinging started. I re-checked the headpipe bolts and found them to be significantly loose. One of them was only snug. I re-tightened them and it seemed to help but now it's back again. I will have to start by looking at the exhaust from the cylinders on back, then work my way toward the PCV and timing tables. By the way, before the new headers I only had the HD Stage 1 download. The bike wasn't quite as lively but until the header leak I put almost 10K miles on the bike with no ping or decel pop whatsoever.

There's no doubt that the heat makes the issue much worse, but this past ride was a very comfortable mid to upper 70's and not much change as the ride progressed. As far as the engine temps, I would think that the engine is going to get up to max heat within 5-10 miles. After that I don't believe it's going to get any hotter unless there is substantial loss of airflow due to too much low speed riding and or idling. I could be wrong however, the ride down the mountain with significant engine braking could very well have driven the temps up and then remained there even when back on flat highway cruising at 75.

One thing I'm going to do on my next ride is take my Infrared Thermo with me and periodically scan the engine and make a log.

As far as timing tables, where would I start if that is the course of action?

Thanks again for all the feedback.

Dan