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Kimbo
7th April 2010, 06:13
I am looking at replacing the plugs on my 2007 XL883.
I have been advised by a couple of members of the Sportster group that I ride with, that if you do not use standard HD plugs in your sporty your ecu can not read your motor, so your knock sensor is turned off and that this is bad because a knock sensor regulates your spark and prevents pinging.:rolleyes::rolleyes:

I am not familiar with the term 'Knock Sensor' or what it's function is ...... but surely you can use other brands so long as they of the correct specifications i.e. heat range etc.?

ReddTigger
7th April 2010, 07:49
you can replace them with a NORMAL spark plug without worries. if you try one of those "Snake oil" plugs you can run into issues.

I run NGK's and haven't had any issues with them in other bikes. I've got customers running NGK's in EFI bikes without any issues..

for the Sporty. DCPR7E for standard plug or a cooler plug is the DCPR8E

williamv1203
7th April 2010, 07:55
Ha... Micro-chipped spark plugs... What will they think of next? :geek

williamv1203
7th April 2010, 07:57
you can replace them with a NORMAL spark plug without worries. if you try one of those "Snake oil" plugs you can run into issues.

I run NGK's and haven't had any issues with them in other bikes. I've got customers running NGK's in EFI bikes without any issues..

for the Sporty. DCPR7E for standard plug or a cooler plug is the DCPR8E

Should I be using this in my primary? :laugh

ReddTigger
7th April 2010, 08:05
Should I be using this in my primary? :laugh

only if it's been approved by the Zen masters at the Motor Company.


:) :D

:p

FoxsterUK
7th April 2010, 09:46
AFAIK the knock sensor isn't connected on any Sportster model. Unless someone has an '07+ wiring diagram and knows different. I believe that the knock sensor pin is there on the later model coils but its just connected to +12V rather than back to the ECU.

Incidentally...Can anyone tell me how it works on bikes with it enabled? There is some signal coming back to the ECU from the coil but how does the coil detect that the engine is too far advanced and knocking?

On some car engines the knock sensor is a crystal microphone that's fixed to the cylinder head and it 'listens' for the banging sound of the engine knocking and this gets fed back to the ECU to adjust the timing. I'm just curious how this gets implemented via an ignition coil on a bike.

FoxsterUK
7th April 2010, 10:01
I found my own answer to that one... http://www.hdtalking.com/diagnostics_and_fuel_injection_related/762-ion_sensing_explained.html

Basically it seems the resistance across the plugs changes in the presence of knocking. Some electronics in the coil constantly measures the resistance from the output to ground (i.e. across the plug gap). This changes in the presence of knocking and a signal is sent back along the 4th wire (ion sensor) connection from the coil to the ECU to adjust the timing to compensate. Changing to different plugs or leads messes up the delicate measurements and makes the readings ineffective, leading to the anti-knock either not working or working when it shouldn't.

I still don't know for sure though whether this is enabled on Sportsters. Only BTs etc are mentioned as having the feature so I suspect not.

dr.feltersnatch
7th April 2010, 11:43
But what about synthetic snake oil plugs?

Baphomet
7th April 2010, 12:00
I'll throw this out there and let your own conclusions be drawn. I was running E3 plugs in my bike for a few months and didn't seem to have any problems (but I did seem to visit the gas pump more often, but never measured the mileage). Anyway, last week my bike started to stall and in a post I started here "Screw Loose Dan" and others suggested I check the system relay and error codes. Long story short, my stalling was from the relay which I replaced.

The only error code indicated that the bike was running rich. I pulled the E3 plugs and they did not show signs of the bike running rich but I put new HD plugs in since I don't reinstall plugs once I remove them (because the compression rings have already been squished). Since then I have put several hundred miles on the bike and no codes have appeared. My conclusion is that the relay was causing the stalling and the E3 plugs were causing the bike to register the code. I could be wrong, but like I said, you can draw your own conclusion.

FoxsterUK
7th April 2010, 12:02
But what about synthetic snake oil plugs?I think if you are going down that route then you will want semi-projected, Iridium-tipped, ultrasound (I kid you not), silver-plated, multiple electrode, CNC-profiled aluminium terminal, nickel-plated body, copper core, tapered ground strap spark plugs.

Tulsaghost
7th April 2010, 15:20
are those the high definition spark plugs?

rick szymanski
8th April 2010, 08:59
I doubt a spark plug(properly gapped, correct thread pitch and length) that's a replacement of another brand will cause any problems. Sure, you can crack the insulator and it will miss. A plug isn't a technology break through. It's a spark plug with different electrode configurations, different plating, still ceramic insulator, but stil just a spark plug. I've see some really crappy plugs pulled from engines that still weren't causing performance issues.

Do they set codes? They can if they misfire. Can they cause performance issues? If the gap is closed and causing misfire, or the gap is so far open with a weak coil that won't fire as well. It will still spark and detonate the fuel usually. I tried opening the gap really far on a bench test for fun. Always sparked. If you break the electrode off it will still spark against the thread sleeve.

Coils that are higher output won't do much for the average consumer. You won't feel the difference. You may pick it up on a dyno, but street use, the bike will feel the same. Drag racing, you'll shave hundredths or thousandths off a time where it may matter. Spark plugs only make a bike run better when they are replacing really, really bad plugs.

Most bikes don't supply the amount of fuel/air to warrant anything performance oriented unless the bike is actually built for a racing application. It's cool to say you've upgraded the ignition system, but I have never seen too many folks that could show me the advantages enough to spend money in that area. For cars, trucks, bikes, and boats....Points vs electronic...hell yeah make the change. Points float at really high RPM.

There's alot of splitfire type plugs out there. The current from the coil only jumps one time to one ground point per fire. It doesn't matter if it jumps to the left or right. Goofy Idea...two tangs on one electrode. Looks faster.

Screw Loose Dan
8th April 2010, 10:04
To the original poster...as others have said, use any normal spark plug and you'll be fine.

AFAIK the knock sensor isn't connected on any Sportster model. Unless someone has an '07+ wiring diagram and knows different. I believe that the knock sensor pin is there on the later model coils but its just connected to +12V rather than back to the ECU.

That is correct. The Sportsters (at least 2007-2009...haven't done the research on 2010's) don't get Delphi's excellent knock detection system. My personal belief is that Delphi (the OEM supplier of Harley's EFI) probably charges a bit more for the feature...and we all know the Sporty line isn't worth that. :rolleyes:

I found my own answer to that one... http://www.hdtalking.com/diagnostics_and_fuel_injection_related/762-ion_sensing_explained.html


This article does an excellent job of explaining the basic concept. I did quite a bit of research on this as I wanted to use a BT ECM (with Ion Knock Detection) on my Sportster. Unfortunately, there is a map of "normal" readings that Harley develops for each engine. If there is one for the Sportster, I couldn't get my hands on it. :( My understanding is this map is quite expensive to develop. And even if I got that map my engine isn't close to stock so it wouldn't be that accurate anyway.

So, I gave up on that project. I did have my Sporty running on a BT ECM for a while tho (there's other issues to work out, like different values for the temp/MAP sensors). I did get the knock detection to "work" as a proof of concept, but I seriously doubt it's accuracy. Testing included cranking up spark advance so I knew I could get it to ping and see the results in the logs...not something I want to do a lot, but I did "succeed" at it.

The only error code indicated that the bike was running rich. I pulled the E3 plugs and they did not show signs of the bike running rich but I put new HD plugs in since I don't reinstall plugs once I remove them (because the compression rings have already been squished). Since then I have put several hundred miles on the bike and no codes have appeared. My conclusion is that the relay was causing the stalling and the E3 plugs were causing the bike to register the code. I could be wrong, but like I said, you can draw your own conclusion.
The only way to get the error code you had is if the O2 sensors detected a rich condition. Unless the plugs weren't firing properly (causing more fuel to be dumped in the exhaust), there's really no way the plugs could cause that error code.

erbie07nightster
10th April 2010, 04:51
you can replace them with a NORMAL spark plug without worries. if you try one of those "Snake oil" plugs you can run into issues.

I run NGK's and haven't had any issues with them in other bikes. I've got customers running NGK's in EFI bikes without any issues..

for the Sporty. DCPR7E for standard plug or a cooler plug is the DCPR8E

I'd like to get some NGKs to put in my bike, but I'm having trouble getting the right part numbers around here. I stopped at an O'Reilly's, and the DCPR7E didn't bring anything up in their system. I've also looked up the corresponding 4 digit number online and the picture that comes up doesn't looke like a regular plug. It looks like it has threads at the top where the plug wire should snap on. Is that what I'm looking for?

erbie07nightster
17th April 2010, 22:52
Okay, I showed a massive dose of ingnorance in my last post. I never knew that the top could be screwed off. Anyway, that aside, I've got my new plugs and was wondering if anyone could tell me the torque specs on the plugs or if any of you even bother torquing them down. Thanks in advance.

Screw Loose Dan
18th April 2010, 02:35
...I've got my new plugs and was wondering if anyone could tell me the torque specs on the plugs or if any of you even bother torquing them down.

According to the FSM - 12-18 ft-lbs (16.3-24.4 Nm)

Can't say I have EVER put a torque wrench on spark plugs. Use the old "Good and snug" measurement. :dunno

You didn't ask - but seems like the next logical question to me...
Gap for the plugs - 0.038 - 0.043 in. (0.96-1.09 mm) - which I almost ALWAYS check.

erbie07nightster
18th April 2010, 03:07
According to the FSM - 12-18 ft-lbs (16.3-24.4 Nm)

Can't say I have EVER put a torque wrench on spark plugs. Use the old "Good and snug" measurement. :dunno

You didn't ask - but seems like the next logical question to me...
Gap for the plugs - 0.038 - 0.043 in. (0.96-1.09 mm) - which I almost ALWAYS check.

Yeah, I've never actually heard of anyone actually putting a torque wrench on them either, but I thought I'd check. I usually just get 'em good an snug, too.

Thanks for the gap. I actually still had that from the last time I changed them, but it's nice to know I got the right number. I usually try to put them at .040, and I never assume that they're gapped right out of the box.

milmat1
18th April 2010, 04:56
I Just want to know IS Synthetic SNAKE OIL really better than regular SNAKE OIL ??

Does Synthetic Snake oil Cause Leaks ?

Tulsaghost
18th April 2010, 05:13
not real leaks tho...faux leaks