Yeah, that's him. Pull those two screws and remove that aftermarket cover. Under the oem cover, there was a flat plate and under that the ignition plate with slotted grooves allowing for timing adjustment. I'm betting the flat plate is no longer there.

I suggested looking in there only to determine if it's all still oem. If it's not, then by definition someone had to adjust the timing.

Please post a pic of what's under that cover.

 

Always had to use 93 Octane in my 2000 RG and my 2010 LTD...always pinged using 91 Octane...octane boost never works that well either...

As wscott mentioned, lowering engine/oil temps will get you there and maybe with 91 Octane won't ping...

1st bike that doesn't ping is my Rushmore with exhaust valve water cooling...

 

I have some torco. You have to use a bit to get results but it does work. It's expensive tho so I'll look into the oil cooler and pcv mod see if that gets me anywhere. I'm willing to bet the heat soak is most likely the biggest problem I didn't notice it when I would take of after stopping for a while, but once running a while I did .

 

grbrown has given you the best advice here. I won't claim to be half the mechanic he is,but on top of his advice,I'll add that I would get rid of those cheap *** accel wires and plugs. I've never seen aftermarket plugs or wires that will out perform stock Harley parts. You probably have no idea what the heat range is on those plugs,and that could be your whole problem.Besides that,that would be the cheapest,easiest place to start.[I did notice you mentioned the possibility of a colder spark plug]

 

The decarbon stuff and getting a aftermarket ignition are good suggestions. I'd check the voes switch as it controls the timing curve. You can simply disconnect it to see if the ping goes away. Mileage will suffer some but you'll know.

 

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FYI,your may not be aware that stock HD plug wires are middle of the road quality at best because they are hi resistance carbon core type plug wires when talking his older gen bike and even my 09 hd had them as stock original equip too,but i am not sure what plug wires they use on todays new HD's.

There are in fact much better quality plug wires avail for his much older hd that are newer gen spiral core plugs wires that were 1st designed for race/hi perf apps yrs back that now avail to gen public use that in fact have 80% less resistance to current flow to the plugs resulting in better overall perf.

I have been using spiral core plugs wires on my bikes and cars for yrs with great results though many cars mfg'd today dont use plug wires anymore due to coils now being directly mounted to the plugs.

As for the plugs,yes if someone didnt bother to properly cross reff stock hd plugs to accell plugs could have ended up with wrong heat range plugs.

And if they happen to be too hot by at least 1-2 heat ranges that could help lead to detonation which may or may no be the case that should be be checkd out like you said .

And if plugs are found to be too hot of a heat range definately need to be changed to proper heat range plugs and tested to see if that stopped the detonation.

But if the Accell plugs check as proper = heat range to stock hD plugs for his app or if plugs were in fact too hot & replaced with proper heat range plugs that still didnt stop the detonation then the plugs arent the issue.

As for tuning ign timingcurve,since his older carb'd bike still has the stock ecm that controls the timing curve getting an aftermarket tuner will allow him to change/retard timing enough to stop the detonation.

But problem with that is when you retard the ign timing 3-4+ deg to stop the detonation that at the same causes the motor to loose x-amount of pwr/trq/throttle response not to mention retarding ign timing can inc engine temp a bit and when your trying to get rid of detonation it's just not the best/proper thing to do by especially when you could be introducing more heat to the motor when retarding the ign timing that can induce detonation due to more heat kind of like chasing your tail,just depends on how many deg you retard the timing along with where in the timing curve its done too.

Last time,assuming ign curve in his bikes stock ecm is reasonable and not way out of wack which is likely ok because OP stated the motor doesnt detonate at all until its heated up to norm op temp for while so the way to best approach is to go after the root causes which are normally things like:

* excessive carbon buildup in combustion chambers (can happen in short time with improper carb tune/too rich) .

That can cause 2 issues,1st is it can raise comp a bit along with the excessive carbon also heating up cherry causing fuel to PRE-IGNITE both of which are an issue when talking detonation.

* removing crankcase breather from stock AC because motor ingesting the overheated oil mist laden gases from the crankcase that can increase comb chambers temps along with the oil mist adding to carbon buildup in comb chambers too bot of which also add to detonation issues.

* too much heat,thats another issue that can lead to detonation.

* lean fuel calibration can increase comb chamber and engine temp both of which can lead to detonation.

Thats how you properly address this issue of detonation by dealing with the root cause rather bandaing it retarding the time loose perf all the way around which is coming from my 1st hand exp wrenching & building motor for classic muscle cars and bikes for over 4.5+ decades & still going strong!

And when you do all i suggest getting comb chambers clean,remove overheated oil laden crankcase gases from the intake,ensure fuel calibration of carb isnt too lean along with cooling the oil up to 50deg f (significantly reduces engine temp @ same time) using the 2 cooling mods i rec doing all 3 of those things at the same results in a significant inc in engine perf you can really feel in the old BUTTOMETER lilke for example:

* ENGINE NOW RETAINS THE PWR/TRQ/THROTTLE RESPONSE IT USED TO LOOSE (ESP IN IN SUMMER HEAT) WHICH IS A SIGNIFICANT BENEFIT YOU CAN FEEL ALL & REALLY ENJOY THE ENTIRE TIME YOUR RIDING!.

* OVERALL ENGINE & VALVE TRAIN NOISE IS SIGNIFICANTLY REDUCED.
ANOTHER SIGNIFICANT BENEFIT YOU CAN REALLY ENJOY THE ENTIRE TIME YOUR RIDING!.

* ENGINE MAINTAINS A SOLID 10-12PSI ADDITIONAL PRESSURE @ IDLE & CRUISE IN SUMMER HEAT THAT'S ANOTHER SIGNIFICANT BENEFIT YOU CAN & ENJOY FROM A PIECE OF MIND STANDPOINT THE ENTIRE TIME YOUR RIDING!.

* AT THE VERY LEAST DETONATION IS SIGNIFICANTLY REDUCED & OR COMPLETE ELIMINATED ESP WHEN 93 OCTANE FUEL IS AVAIL. ANOTHER SIGNIFICANT BENEFIT YOU CAN HEAR & ENJOY FROM A PIECE OF MIND STANDPOINT TOO THE ENTIRE TIME YOUR RIDING!.

BUT IN THIS CASE THE DETONATION MAY ONLY BE REDUCED ON THE OP'S OLDER BIKE BECAUSE ONLY 91 OCTANE FUEL IS AVAIL FOR HIS OLDER MODDED ENGINE WITH NEWER/FRESHENED UP TOP END AND WE ALL KNOW LRG DISP hd V-TWINS ALL SEEM TO RUN & PERF BETTER ON HIGHER 93 OCTANE FUEL.

* BIT LESS HEAT IS HITTING THE RIDERS. ANOTHER SIGNIFICANT BENEFIT YOU CAN FEEL & ENJOY THE ENTIRE TIME YOUR RIDING!.

NOW HOW COULD ALL THOSE BENEFITS NOT BE WORTH GOING AFTER ESPECIALLY WHEN YOU TAKE INTO ACCT ALL TIME/HRS/MILES WE SPEND ON OUR HD'S NOT TO MENTION THE BUCKS WE SPEND ON OUR BIKES @ TIME WHEN FOR EXAMPLE DROPPING $800+ FOR NEW A NEW EX SYSTEM THAT CANT GIVE YOU ALL THE ABOVE BENEFITS THAT NOT ONLY CAN SIGNIFICANTLY REDUCE & OR ELIMINATE THE OP'S DETONATION ISSUE ALL TOGETHER BUT CAN ALSO INCREASE OVERALL ENGINE PERF AND RIDER COMFORT ALL AT THE SAME TIME TOO.

After thought,there's another thing being totally overlooked here when it comes to detonation which is OP hasn't told us (unless i missed it!) the comp ratio & cam timing (Duration,LSA etc) of his newly freshened top end.

Compression ratio vs cam timing has a large affect on what octane requirement is for his motor that could in this case be creating enough cyl pressure to require 93+ octane fuel when he's trying to run it on lower 91 octane fuel without detonating under load when the motors heated up which isnt a good situation.

A stock or mild cam with short cam timing can create too much cyl pressure for 91 octane fuel to handle without detonating with only 9.0-9.2-9.5 compression where if he had same compression with a cam having significantly more cam timing (more duration increasing valve overlap enough to reduce cyl pressure thus lowering the motor octane requirement in the process.

Happy Motoring!

Scott

 

scott good write up! I suggested changing wires and plugs,because I've had problems w/accel parts before,and that is simple and easy-worth a try.I wonder how old the wires are? A lot of unknowns here-but I don't see slapping on hundreds of bucks worth of cooling fans and oil coolers to try to solve the problem,as some have suggested.
I also agree that the stock Harley wires are minimal,but they are what the bike ran fine with it,when it was built.
Hoping the OP gets this fixed quickly!

 

So you are saying that you shouldn't retard timing on a high compression build?

Spark plug wires will fix the ping?

I always thought it was intake close that sets CCP and not overlap?

 

I mentioned that I think it has been re camed but I have no idea what it has . I'm not completely novice when it comes to cam timing and compression nor the effects of heat range of plugs and ignition timing. I've been building and wrenching on hotrod cars for years and even have a turbo sbc with a blow-thru carb . I just don't know the numbers harley engines like . I'm limited to 91 pump being the top grade fuel I'm my area. Yes the more overlap a cam has will lower the effect static compression but dynamic compression will dictate the octane required for a given combination. Hooking up a timing light and all is simple enough so is figuring compression on cylinder pressure but I don't know where to start with the tune. The carb has been adjusted to the spec outlined in s&s manual. It seems to run well and strong. Oil cooler seems like a good option for the fact it can't hurt to have. I'll probably pick up some 110 fuel and run a tank of that to see if it runs better .

 

Good discussion.. If the bike has a cam, for sure go to a better than stock ignition, DTT or Dynatech.. Much easier to set timing on. I run much higher compression that what a stock 96 FLHT runs (even with a cam) on 91 octane without issues.