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Just an FYI and my opinion. I recently started my 03 ST4S after the winter. I had started it a couple times throughout the winter but had not ridden it. Long story short the spark plugs fuel fouled. I replaced the Champion plugs with NGK (R-2525-10). This made for a unbelievable difference. Even compared to before the original plugs fouled. The bike doesnt even turn over one time before it fires up. Very good investment and I would recommend to anyone looking to change plugs. The plugs came from sparkplug.com. They were $10 a plug cheaper than I could find local (still $27 a plug). :D
 

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Update

Hi, Just wondering if the original poster was still happy with the plugs. I do get winter starting problems even with a conditioner plugged in so would welcome any other plug suggestions for the ST4s
 

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Update

Just about to buy new plugs and wondered whether , after a year , the E2525-10's were still performing well.

I have looked at the alternatives for my 01' ST4s and drew the following (Original Champion RA59GC-Gold Palladium):-

Champion RA59PP (Double Platinum)
Champion RA4GHC (Gold Palladium)
Champion RA4HC (Standard)
NGK DCR9EIX (Iridium)

The R2525-10's were not listed by this particular supplier

What is the combined wisdom out there ?
 

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+1 on the NGKs. I use the DCPR8Es. But also a comment. If you're in a climate where you actually store your bike over the winter, it is not a good idea to periodically start it. Just let it sit. Starting it creates all sorts of fun, just like the one the OP had. You will most likely not be able to run it up to temperature properly. If it's really that cold, you'll likely end up with condensation problems when you shut it down like the milky oil threads we see every winter. Leave it be, happily hooked up into a battery tender, with some fuel stabilizer added, and all will be fine when it comes time to take it out of hibernation. Just my 2 cents!
 
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SS904 said:
+1 on the NGKs. I use the DCPR8Es. But also a comment. If you're in a climate where you actually store your bike over the winter, it is not a good idea to periodically start it. Just let it sit. Starting it creates all sorts of fun, just like the one the OP had. You will most likely not be able to run it up to temperature properly. If it's really that cold, you'll likely end up with condensation problems when you shut it down like the milky oil threads we see every winter. Leave it be, happily hooked up into a battery tender, with some fuel stabilizer added, and all will be fine when it comes time to take it out of hibernation. Just my 2 cents!
I endorse that - my ST4s is laid up every winter here in Swiss Alps from end Oct through to start April. Gets new plugs every 6k mls (NGKDCPR9E) and is never fired up during its hibernation. Result - no hesitant starting, no milky way in the sight glass and no spark plug failures in-between services since June 2001.
 

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Iridium Plugs for ST4s

I thought I would just advise that I have just taken the bike (MY 01 - ST4S) out for a good run after fitting Iridium Spark Plugs and I have to say that I was amazed at the improvement in driveblity.

I dont think they provide any more power but the engine now fires really evenly and this makes for a big improvement at low revs on a light throttle.
Whereas before it sounded like there was an occasional but fairly frequent "miss" on the firing the engine now pulls really cleanly and even my wife noticed it whilst on the back.

I know it was not just the benefit of new plugs because the bike has always reacted the same on the standard plugs old or new.

FYI they are NGK DCPR9EIX's and I highly recommend giving them a try , but please post a comment if you do as I would value a second opinion.
 

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Gearbox said:
please post a comment if you do as I would value a second opinion.
Same here - irridium for 3 years now (same set) with excellent results. One thing: you should open up the gap on plugs that have a fine wire center electrode such as irridium or platinum. I run mine at 1.0mm (0.040 inch). Since they fire easier it's a good idea to open up the gap to compensate.

Be careful when you open up that gap - you can't touch that little center electrode. Use a plug gapping tool to bend up the side electrode a bit.

I also changed to the KV85 Magnacore plug wires - red ones! There was nothing wrong with the stock Ducati wires (a bit stiff) but I had this money burning a hole in my pocket...
 

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Cheers

Shazaam said:
Thanks "Shazaam" for pointing me at that article , It made very interesting reading and seemed to bear out what I felt on the road.
Interesting to note that there maybe more improvement yet to come , I'll take the plugs out a regap them when I get a chance and post if anything of significance occurs.
 

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New plugs and first time post

I just got my 02 ST4s...first Ducati I've ever owned. I purchased from Honda Yamaha of Fort Walton Beach. They had a hard time starting the bike because they didn't really know how. The sales man kept opening the choke all the way and flooding it and fouling plugs, telling me the whole time "no it has carbs". I took it home started fine for a few days they told me the replaced the plugs...pulled them out tonight, guess what...they lied. I looked on the board did the search and bought some standards NGK plugs, part number DCPR8E. It fired right up and ran great!

My question is what is the difference between the DCPR8E and the DCPR9E plug I've seen mentioned in this thread...is one hotter than the other? Which one should I really run?

I've also ordered some NGK DCPR9EIX from Advance Auto Parts and they will be here in a few days...only $4.53 a each that I may swap to when they arrive. In the meantime I'm just doing all the small stuff to the bike to get it ready for the summer.
 

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Resurrecting an old thread.
I would like to do some simple maintinance on my 2004 ST4s and I am looking for spark plugs. Is the NGK DCPR8E the way to go? I have seen a few plugs at $4 bucks to $34 bucks. This is all new to me. From my little bit of research I think mine are Champion plugs. But alot has changed in plug science since 2004. Please help. Where to buy..

Thanks.

A terrific site for info.
 

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Re irridium plugs. I asked Chris of Ca Cycle Works as to the value in switching to the higher priced spread. He said to just stick with the regular. No real benefit to switching. Sooooo, I followed his advice. Life's too short to be testing for the 'Nth' degree of improvement.

S
 

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Re irridium plugs. I asked Chris of Ca Cycle Works as to the value in switching to the higher priced spread. He said to just stick with the regular. No real benefit to switching. Sooooo, I followed his advice. Life's too short to be testing for the 'Nth' degree of improvement.

S

Generally true from a "new (regular) plug" performance standpoint. Having used the iridium plugs for a while now, I find they stay "new" for a long time, which is the whole point. They are a performance item only in that they feel like fresh regular plugs for a very long time. Regular plugs I would replace every 6K at the valve check interval and could feel the difference in performance. IX plugs can go much longer (I've done 18K with the ST4s) and still offer the smoothness and crisp throttle response of new regular plugs. Consider why they exist at all. They are specifically made to meet newer automotive fuel mileage and emission standards over 75 to 100K or more miles . I have a company car for work and we get a new car every three years. The only preventative maintenance we get to do are (conventional) oil and filters every 5K. I am coming to the end of the lease on my 3rd car now and all have had, or will have, between 130 and 150 miles on them when I swap them out. I have never changed the plugs on one. Worth it? Up to you, but the reason new plugs feel good is because the old ones have degraded slowly over time and are offering poor performance and gas mileage at the end. To me, it's worth it to maintain the same performance level as new for that many miles.

I will add, many have had running issue just popping in the IX plugs. If you have a weak ignition you will have problems. They need to be gapped correctly and you need to have good wires. I have the red (8.5MM?) Magnacor wires on both bikes, plugs are gapped wider (forget what it's set at). The rest of the ignition is OEM and the bikes run very well, minimum to no missing and crisp throttle response. Tuning properly helps, but the plugs are part of that.
 

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Resurrecting an old thread.

I would like to do some simple maintinance on my 2004 ST4s and I am looking for spark plugs. Is the NGK DCPR8E the way to go? I have seen a few plugs at $4 bucks to $34 bucks. This is all new to me. From my little bit of research I think mine are Champion plugs. But alot has changed in plug science since 2004. Please help. Where to buy..



Thanks.



A terrific site for info.

Iridium plugs are older than most people realise. I put my first set in Kawasaki KH250 that struggled to keep its plugs clean during slow speed town work- especially in the wet. A set of iridium plugs cured it completely.

I can't say how that has a bearing on modern engines-particularly four strokes-but that was a clear improvement in a dirty little two stroke.



Sent from Motorcycle.com Free App
 

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Wasn't it the larger triple Kawasaki's that even carried a spare set of plugs because of the problems they had ?
 

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Brisk Plugs

I have used Brisk Plugs in my VFR and got 40 more miles per tank and smoother running at high rpms. Had Has anyone used them in a Duck? I've an 03 ST4S.
 
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