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Old 03-04-2011, 03:39 AM
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Exclamation Changing to a hotter spark plug, good idea??

Ok heres a question for those more knowledgeable than me.

I'm getting a dyno tune from a very respectable tuner, AF1Racing,here in Texas.
AF1 Racing / Apriliaforum.com : Aprilia Performance Parts and Accessories

They have recommended switching to one heat range hotter of a plug to reduce the possibility of fouling.

Good idea? Has anyone done this before?
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Old 03-04-2011, 01:09 PM
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Which work have you carried out on the engine?
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Old 03-04-2011, 04:29 PM
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I probably have 250-300 hours of dyno time with RC51's and I have never fouled a plug



I have seen plenty of well acclaimed & competent tuners of other makes/models of sportbikes not know the first thing getting the most out of an RC51. If I had a dollar for every incorrect target A/F ratio I have seen applied to an RC51 tune by a reputable tuning company I could go buy a box of .357 Magnum ammo
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Old 03-04-2011, 04:33 PM
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IFR9H11 (sp-2) next topic ?
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Last edited by wingnutt; 03-04-2011 at 04:52 PM.
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Old 03-04-2011, 04:50 PM
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RC51 Spark Plugs (all are Iridium plugs) From Rogue site
SP1
FR9BI-11 (00-01 NGK)
IK27C11 (00-01 NIPPON DENSO)
SP2
IFR9H11 (02-03 NGK) 31919-MEB-671
IK27PRZ11 (02-03 NIPPON DENSO) 31919-MEB-672

From Honda Parts Catalog listed in a on online- discount parts Cycle-Parts.com (part number 19 on Front Head)

SP1

19 SPARK PLUG (IK24C11) (DENSO) (OPT) 1 $39.56
19 SPARK PLUG (FR8BI-11) (NGK) (OPT) 1 $11.63
19 SPARK PLUG (IK27C11) (DENSO) 1 $25.69
19 SPARK PLUG (FR9BI-11) (NGK) 1 $11.63

SP2

19 SPARK PLUG (IFR8H11) (NGK) (OPT) $13.69
19 SPARK PLUG (VK24PRZ11) (DENSO) (OPT) $12.14
19 SPARK PLUG (IFR9H11) $17.80
19 SPARK PLUG (IK27PRZ11) $10.23


The 24 is a hotter plug and corresponds to an NGK 8 and your manual is listing this as a possible winter riding plug, which translates to only use it if you are fouling plugs in the winter. The IFR is so rare that when you plug it in Google only RC51 and CR450xs come up!

NGK - ND (Nippon Denso, not Denzo) Heat Range
7 - 22
8 - 24
9 - 27

The 11 at the end is for the gap, they are pregapped to 1.1mm (1.05-1.15) and should not be manually gapped or may be damaged.

I wondered what's the difference from IK to VK and they are both Iridium but different lines (Iridium & Iridium Tough, there is also I.Plus and I.Racing in ND plugs) From ND's site:



IK series
IK16. IK20. IK22. IK24. IK27. IK31. IK34. IK16G. IK20G. IK22G. IK16L. IK20L
・ Mainly used for cars. ISO type. ・ 14mm dia. X L19mm length type. ・ IK22 and above are for tuned engines, with a spark gap of 0.8mm. ・ IK16G, IK20G, and IK22G have a solid, stainless steel gasket (mainly used with Honda engines). ・ IRIDIUM TOUGH VK16, VK20, and VK22 are also on sale at the same time. ・ IK□L is extended type (spark position 5mm)

VK series
VK16. VK20. VK22. VK20Y. VK16G. VK20G. VK22G
・ Mainly for automobiles and trucks ・ ISO-compatible small plug ・ Mounting base: 14 mm dia. X L19 mm ・ VK16G, VK20G, and VK22G have stainless steel gaskets. ・ VK20Y has a gap of 0.8 and is mainly for use with turbo engine vehicles.





If you are in the US go to Advance or AutoZone and get your plugs at around $9-11, you may also find equivalents to Honda oil filters in Purolator numbers as well as other brands at fraction of cost.

Lifted from the internet someplace !
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Old 03-04-2011, 10:55 PM
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Quote:
Originally Posted by DesperateSP2 View Post
Which work have you carried out on the engine?
No internal work. Just Turn one airbox and snorkle.
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Old 03-04-2011, 11:02 PM
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Quote:
Originally Posted by LDH View Post
I probably have 250-300 hours of dyno time with RC51's and I have never fouled a plug



I have seen plenty of well acclaimed & competent tuners of other makes/models of sportbikes not know the first thing getting the most out of an RC51. If I had a dollar for every incorrect target A/F ratio I have seen applied to an RC51 tune by a reputable tuning company I could go buy a box of .357 Magnum ammo
I know these guys did suprajoe and supposedly a few other RC51's so hopefully all will go well.
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Old 03-05-2011, 12:01 AM
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Quote:
Originally Posted by LDH View Post
If I had a dollar for every incorrect target A/F ratio I have seen applied to an RC51 tune by a reputable tuning company I could go buy a box of .357 Magnum ammo
and that shit ain't cheep these days.


seriously though dude throw in a set of fresh plugs and let it eat. I have no Idea why he would recommend such a thing. My tuning methodology on a dyno is to start rich under load and creep down until I gain peak torque, and then go just a touch fat for safety. under large amounts of forced induction I've run stock heat range ngks down to 10:1 and never fouled them. so if this dude is going anywhere near that kinda fat run the other direction. you'll prolly find peak power in the range of mid to low 13's and should have no problem with fouling at those ranges.
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Old 03-06-2011, 04:48 AM
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and that shit ain't cheep these days.

No it ain't...
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Old 03-06-2011, 09:55 PM
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look up opp.racing at the Brisk plugs there great on mine
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Old 03-07-2011, 12:46 AM
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Originally Posted by Dukie View Post
look up opp.racing at the Brisk plugs there great on mine
Thanks for the link!
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Old 03-07-2011, 01:32 AM
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Originally Posted by Dukie View Post
look up opp.racing at the Brisk plugs there great on mine
Oh really? I am sure you have something to back that statement up right? Before & after dyno charts? Oh wait let me guess you installed them and it felt like you had more horsepower right?
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Old 03-07-2011, 01:34 AM
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wish I did,But it was a noticable differance
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Old 03-07-2011, 01:37 AM
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I've had RC51 riders tell me the exact same thing over & over again about K&N air filters right before I proved to them they actually hurt the performance of the bike

Placebo effect is a wonderful thing until you learn the truth
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Old 03-07-2011, 11:55 AM
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I suspected as much. A hotter plug would make very little sense.

PS: LDH, that thing about K&N filter seems to be like an infectious disease. A friend of mine (actually the chap who sold me the SP2 ) has just bought another SP2 and he immediately wanted to buy K&N. I had he come over to my place, gave the bike a good service (though I will be seeing that bike again) and just cleaned the OE stuff as per manual (compressed air).
No more talks of K&N after he saw what came out of them...
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Old 03-07-2011, 03:44 PM
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Quote:
Originally Posted by DesperateSP2 View Post
I suspected as much. A hotter plug would make very little sense.

PS: LDH, that thing about K&N filter seems to be like an infectious disease. A friend of mine (actually the chap who sold me the SP2 ) has just bought another SP2 and he immediately wanted to buy K&N. I had he come over to my place, gave the bike a good service (though I will be seeing that bike again) and just cleaned the OE stuff as per manual (compressed air).
No more talks of K&N after he saw what came out of them...

just do the screen mod on the OEMs and it will make more of a difference then the K&Ns
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Old 03-08-2011, 03:37 AM
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So according to what wingnutt posted an IK20 is 3-4 steps hotter than the IK27... So to do the CBR coil mod I need plugs. I picked up IK20's because according to this site: DENSO SPARK PLUGS they are stock for the SP2's. So before I put them in can I run the IK20's in my SP1?
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Old 03-08-2011, 01:07 PM
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Quote:
Originally Posted by wingnutt View Post
Lifted from the internet someplace !
You did well to have lifted it as I had placed that table on two other forums but forgot this one.

But a 20 is way off the chart and very hot. Hot enough to burn a hole on your piston. It's even too hot for a 2stroke, except for maybe some watercraft engines.

And an IK is not the right plug for an SP2, go read that table.

The reason Honda has the NGK 8 as an option to the 9 for winter riding is that when the engine is really cold, the fuel is cold, and air is cold, fuel does not atomize well or liquifies itself into drops in the chamber and stays unburned, in this case it may foul the plug. But it is only important during starting. If you start the bike that is stored in a garage that is warmer than ambient air it is probably unnecessary. Also, unless it like 20'f outside, leaving the bike parked for a couple of hours for coffee/food will not be enough to create a problem, especially if sunlight is heating the tank.

An engine that runs too rich and fouls a 9 will most likely foul an 8 as well. So a plug is not a fix for a rich condition.
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Old 03-09-2011, 03:00 AM
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Zero... Not doubting you and I purposely didn't install them tonight waiting for an answer. But the link I posted clearly states the IK20 for the SP2....
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Old 03-09-2011, 07:48 AM
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It's a misprint for sure, it is the only bike they have listed with a 20, that should clue you in. The heat range for SP1 & SP2 is the same

27 is standard, 24 is optional for very cold weather. 22 is too hot for and 20 is for burning oil
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