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I had posted about a week ago about my spark plug woes and found not one owner with similiar problems.

I am attempting to replace my spark plugs myself while I'm replacing my leaking battery.

I bought the replacement plugs from Pro-Italia ($18.95 each) only to get home and realize the terminal was solid, the cap did NOT remove. (AS NEEDED)

I then returned those to Pro-Italia, as they did not have the proper ones.

Then I went on Sparkplug.com and ordered the proper NGK plug (DCPR9EVX) ($6.40 each)

Once again, upon arrival the terminal was solid the cap did NOT remove. So I called Sparkplug.com and explained my frustration.
They were very helpfull and sent me out what they said was the proper plug, (DPR9EIX-9). Same price.

So they arrived today and sure enough the terminal is exposed as needed but the plug uses a 18mm socket instead of a 5/8 spark plug socket.

The 18mm socket will not fit down the spark plug shaft....................

Can you say......I'M GETTING REALLY REALLY FRUSTRATED!!!

Do any of you S4 owners have any ideas, or have you all just had the dealer chang your plugs.....(or have they?)


I JUST WANT TO PUT MY BIKE BACK TOGETHER WITH THE RIGHT SON OF A B***H SPARK PLUGS, MADE EXCLUSIVLY FOR YOUR ONE AND ONLY IN THE ENTIRE UNIVERSE DUCATI MOTORCYCLE......SO BEND OVER AND PAY $18.95 A PIECE
 
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i swear on my carbon fiber i am not being a smarta$$, but did you try the little tool jobby thing in the tool kit. i ran into the same problem on my s4. the tool kit wrench sticks out enough to get something on it to turn it.
 

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I went though the same thing first plug change. Bought my NGK's at the local Japanese bike shop. No prob, they had the right number (DCPR8E). Same thing. Couldn't get the cap off. Put in the vise. Broke it off. Never saw one before that wouldn't screw off...took them back to the Japanese shop. They said, "Ha, it just screws off". I said, "Really? Show me." They snapped the other one off. Got my money back. Went to the Duc shop. Bought THE SAME NUMBER plugs. No cap at all on these puppies. Went right in...

But, there is another number...the number on the end flap of the box is different. Above the DCPR8E is a four digit number, #4339. This, I guess is the REAL plug number. The other number normally works for most applications; but not ours. I think each letter/number in that one is a code for thread pitch, thread depth, type of electrode that sort of thing. But, for some reason, it doesn't reflect the terminal style.

I don't know why my plug numbers are different than yours (I am curious now). I noticed Chris Kelly sells the plug you are looking for. The number plug I'm using (DCPR8E) is the same one that GP put in at my 6000 mile service. It's also the off-the-shelf plug handed to me at ECS, and after 3000 miles, seem fine. ($3.55 from the Ducati dealer)
 

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Just checked this on my '02 S4...

Hole in the head is 0.938" diameter.
My Craftsman 6-point deep 18mm socket is 0.923" diameter, and appears to fit down far enough, I've still got the OEM 5/8" hex spark plugs in, so I can't say_absolutely_will fit, but.....

You'll have to wad some paper in the socket (or something) to keep the plug in the socket to install in the vert cylinder. Tape the socket onto the extension to reduce swearing, DAMHIK.
 

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Discussion Starter #6
Thanks Tom and VincentS4,
I did try the tool kit and the tool fit the 5/8's stock plug.....
but not the NGK

Tom, the stock plug I pulled out was a Champion RA59GC. That's the plug that is exclusivley Ducati, also is listed in the manual. (18.95 each)
 

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I just did a NGK search. The plug I'm running, DCPR8E (stock #4339), is a non-Iridium plug specified for a 1994 916. All later 9*6 SBK's take an Iridium plug DCPR9EIX (stock #4383). However, later 748's also use my plug, the DCPR8E, so I don't think it makes any difference. (other than $$$)

http://www.ngksparkplugs.com/apps/default.asp?nav=60000&country=US

Q: What do the numbers and letters in a part number represent?http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqcode.asp?nav=31200&country=US
 

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Hey Ducseven,

S4's can be very frustrating, but once you tweak little things here and there, it always works out. I highly recommend the NGK's, not really sure what the number but can check if you want. For some odd reason, some plugs come with 5/8 heads and others 18mm. What you need to do if you want to use a socket head, go buy a cheap one, grind down the outsides untill it fits down that hole. I got this tip from the ducatisuites website. Get a cheap socket because the metal will be softer and easier to grind, then you con through the torque wrench on there and get that big ol 20nm's on the plugs.
 

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DCPR family of plugs have almost always been solid top (non removable). these are REQUIRED in the 4V engines with the dropped exhaust cam (as found in 2002+ 748 and all ST4). the plug well is too small to allow any 18mm socket.

the 4V heads with the cams "level" or both at the same height can use other NGK plugs, like the D8EVX.

note that the platinum plugs (that i'm so in love with) are a thing of the past. i have like the last 12 commercially available platinum ngks on my shelf right now. then i'll be researching the ND non resistor platinum plugs.

i really don't like the iridium plugs and the fact that they all mandate resistor core. the WM electronics on ducatis are not susceptible to rfi, so that's really not an issue.

champion = cut threads = bad
ngk = rolled threads = good

:) chris
 

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Just checked this on my '02 S4...

Hole in the head is 0.938" diameter.
My Craftsman 6-point deep 18mm socket is 0.923" diameter, and appears to fit down far enough, I've still got the OEM 5/8" hex spark plugs in, so I can't say_absolutely_will fit, but.....

You'll have to wad some paper in the socket (or something) to keep the plug in the socket to install in the vert cylinder. Tape the socket onto the extension to reduce swearing, DAMHIK.
Not to be a broken record, but y'all seemed to have missed my post.....
 

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Discussion Starter #11
Thanks for the input guys,

Nick, just for the record, I just got home with a 6 point 18mm spark plug socket and it doesn't fit down the well.....of my S4 anyway.

I guess I will be returning these plugs (and 18mm socket) and looking for the DCPR8E with the removable terminal.....

BTW, I was also told by Pro-Italia that the bike has those Champions in it because the computer is different than my 95 916.......Does that make any sense?


THANKS AGAIN,
Rob
 

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Shoot...sorry if I led you down the wrong path. My 18 socket looks like it'll work, but I don't have the plugs, so.... :(

I think the Champion plugs are used because of the small physical size. I'm no Electrical Engineer, but I don't think that the computer can 'see' the plugs on the other side of the coils.

I don't recall anybody else posting on this issue...

I know it's not much consolation, but thanks for 'taking the bullet' on this one for the rest of us.
 
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