Good evening,

I have been following the various threads regarding pinging/knocking. My 2012 FLHRC recently started pinging under load. Prior to that I swapped out the stock cams and put in Andrews 57H. Had a small timing issue that took my mechanic to find, but since that point the bike ran great - no pinging.

Since it started I have run numerous 91 octane tanks through it from reputable gas stations so I don't think that is the issue.

It seems that it started pinging about the same time I replaced the plugs. I bought new plugs this weekend, gaped them and the pinging still continues.

I have a PV and have included the log from my 1 hour ride. I can see that there is spark knock on both the front and rear. The front pulls about 2.5 degrees max and the back seems to pull about 4.5 max at higher RPM's

I have attached the log in hopes one of the tune/engine geniuses can help me figure out why this has started.

Should I just use the quick tune feature and decrease spark by 2 degrees?

I am not very good with such things so any help will be truly appreciated.

Thanks!

 

You can manually edit your Spark tables in the areas it's detecting knock. At a quick glance it's detecting a little in the 40-60kpa areas both front and rear.. If you want you can email your MAP to me at chad@wideopencycles.net and i'll make a few quick changes and you can do another data log.

 

Just a thought - what plugs did you put in - the ION knock sensor is sensitive to plug type and plug gap. You may have been running close to the edge of some pre-ignition before you changed plugs but the knock sensing was pulling some advance that it is not pulling now. Correct HD plugs and wires?

This isn't to imply you don't have an advance or other tuning issue, but may explain why it only showed up after changing plugs..

 

Thanks for both replies.

First - I will get the map to you this coming weekend. I travel during the week and I really appreciate the offer. Right now my current map is the result of an auto tune - does that matter or do you want the base map?

Second. The plugs that were replaced were auto zone plugs. I had read about the ion sensing and that is when I bought the 6ar12 (I think) from Harley. They were $10 for both. Parts guy said no need to buy the $20 set.

Thanks!

 

Oh and the gap on the new are right at .38 on one and the other is .40. Came that way so I did not gap since both are within tolerances.

 

I might be beating a dead horse, but if you've got the original plugs, I'd put them back in and see if the knock events go away. I chased some pretty significant knocks under WOT upper mid-range on the TG, swapped plugs between cylinders, knock events went with the plug. New set of plugs gapped .035, no more knock count on PV.. As I said before, you might have an underlying issue that ION sensing was masking.. I just don't like the fact that this was introduced at the same time you changed plugs..

 

Send the current autotuned MAP . scooterbum46 is correct about the plugs. The wrong ion sensing plugs can give a false positive on spark knock. If you have good hearing and can't hear the ping, there's a good chance it's a false positive. The quick glance I took at your log shows that it's pretty consistent so it's probably a legit reading.

 

I had a quick look at the log and there seems to be more knock than just the 40-60?

Can I ask what constitutes knock (or what to worry about anyway)? is it anything other than zero or only if it gets up to 2 or 3 degrees. I see a little in mine for example but only traces of 0.5 and 1.0's

cheers

 

If you are logging IONQ Voltage, along with Knock Count, you'll see the voltage that the count increases at ... IIRC (I'll have to look on the other 'puter later) it's around 2.5 volts that it indexed up at.

 

True knock.is pre-ignition. The plug fires to soon in the combustion cycle (piston isn't up enough in the cycle before the spark ignites and tries to force it back down). Ideally you don't want any. That's are different approaches on how to cure spark knock. Retarding the ignition timing or adding fuel to the effected area is the most common. running higher octane fuel or running a cooler spark plug can also help.