OZ ATV :: The Australian ATV Forum

[crx450r]

Iridium vs standard spark plugs
what's everyones opinion???
are they worth the extra $$$$???

[Dino]

I got nearly 40 thousand out of the first set in our subaru. Most of that was urban km. Given that a coupla of them aren't easy to change, and they cost me 2 and a bit times the price of standards, I reckon they're a winner in our car.
I didn't pay the $28 plus tax each the dealer was asking.
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Remember. We elect politicians, but we have to deal with bureaucracy.
Notice that crazy in the bureaucrats.

Last edited by Dino on Tue Mar 23, 2010 2:42 pm; edited 1 time in total

[Earthmover]

our falcon AU lll only takes 1 or 2 types of plug I'm told we have done well over 70,000kms towing back and forth to vic & nth qld and only ever changed 1 plug and changed the oil once to for that matter good car
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[crx450r]

the reason i ask is i'll foul a plug about once a month on my bike
and my local bike shop doesn't keep the plugs in stock so he wants me to buy a box of 4 $96 +gst+ freight
trying to find out if there are worth it???

[Earthmover]

trx435 wrote:

the reason i ask is i'll foul a plug about once a month on my bike and my local bike shop doesn't keep the plugs in stock so he wants me to buy a box of 4 $96 +gst+ freight trying to find out if there are worth it???

sparky's don't just go bad that often there must be an underlying problem like air fuel mix . I don't know if you would like to then go wast $30.oo + on a plug every 5,6 weeks instead of i don't know ? $15.oo every 4weeks I'd just get one and try it out
_________________
If its got wheels I'll drive it!

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[NeKeleC]

I would be going to repco (or similar) to buy the plugs good chance they will be cheaper also as previously stated check your plug colour you could have air/fuel mix issues and also make sure you gap the plug before putting it in.
Edit- forgot to mention iridium plugs are better I had a set in a hot four cylinder car for 90.000ks and were still going strong changed only to prevent failure.
_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[crx450r]

as far as i can tell the air fuel is fine
i've been told the plug failure is because of the hi compression piston change

[elmerkit]

Hi there, any way to answer the question i prefer to use stock plugs and just change it every 3months. better to have fresh plugs rather just cleaning it up. as far i I know iridium plugs are good for competition purpose But will not be so useful for every day use.
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"Invest with atv parts that are reliable and inexpensive."

[crx450r]

iridium was working great until......
i blew a head gasket
so the spark plug is the least of my worries at the moment
cheers for the input

[HaggLE]

My father's BA Falcon has iridium plugs, has 110,000k's on it and started to misfire on cold start, the original iridium plugs had worn to a gap of 2mm. Once gapped back to the standard 1.4mm they were fine.
Basically, you can get longevity out of iridium but you have to make sure everything else is right (like head gaskets and a/f mixtures)

[NeKeleC]

If you are getting plug miss firing after putting in a high compression piston it sounds like you are getting "spark spuash" this occurs when you increase compression by making the air more dense or compressed you make it harder for the plug to fire, check your gap setting this will be different for standard compression and high compression. Also you are running a honda so look into a NGK plug (hondas coil will run them others burn out, aftermarket coils are ok) i can't remember the exact number i think it's an EV or EG type plug (about $40 each) a bit dear but well worth the money i had one in my 96 CR 250 could not kill the thing did whole race seasons with them then kept them for spares, normal spark plugs fire at 1400v these things fire at 14,000v. you need to get one number colder plug then standard for your bike and make the fuel a bit richer they add instant HP.
_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[cuzo]

Question:

The bike has just recently not starting, every thing is turning over fine but seems to be not firing, could this be the same problem??

Changed plugs but still no joy, it dose though have a high comp piston.

If I squert Start yar b*&^ted Down it it gose and when it has warmed up it starts first go every time.

any Idears ??
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04 Polaris Predator 500 with mods
ProArmor - Revolution nerfs

[azza450]

Have you checked the valve clearances?

[crx450r]

NeKeleC wrote:

If you are getting plug miss firing after putting in a high compression piston it sounds like you are getting "spark spuash" this occurs when you increase compression by making the air more dense or compressed you make it harder for the plug to fire, check your gap setting this will be different for standard compression and high compression. Also you are running a honda so look into a NGK plug (hondas coil will run them others burn out, aftermarket coils are ok) i can't remember the exact number i think it's an EV or EG type plug (about $40 each) a bit dear but well worth the money i had one in my 96 CR 250 could not kill the thing did whole race seasons with them then kept them for spares, normal spark plugs fire at 1400v these things fire at 14,000v. you need to get one number colder plug then standard for your bike and make the fuel a bit richer they add instant HP.

i'm limited to they type of plug only denso make an iridium for the 400 ex
i'm using a xr 600 spark plug re gaped
just waiting on price back about an msd enhancer ignition system at the moment 2

[crx450r]

NeKeleC wrote:

If you are getting plug miss firing after putting in a high compression piston it sounds like you are getting "spark spuash" this occurs when you increase compression by making the air more dense or compressed you make it harder for the plug to fire, check your gap setting this will be different for standard compression and high compression. Also you are running a honda so look into a NGK plug (hondas coil will run them others burn out, aftermarket coils are ok) i can't remember the exact number i think it's an EV or EG type plug (about $40 each) a bit dear but well worth the money i had one in my 96 CR 250 could not kill the thing did whole race seasons with them then kept them for spares, normal spark plugs fire at 1400v these things fire at 14,000v. you need to get one number colder plug then standard for your bike and make the fuel a bit richer they add instant HP.

i'm limited to they type of plug only denso make an iridium for the 400 ex
i'm using a xr 600 spark plug re gaped
just waiting on price back about an msd enhancer ignition system at the moment 2

[NeKeleC]

Does the bike have any spark when cold?
Is the plug gap ok?
It could be jetted too rich (cold starts wet the plug and it won't fire - even worse when gap in plug is too big)
Check your timing this also can affect things when you up the compression from memory i think it needs to be slightly retarded for higher compression
Start ya B@#stard is only aerostart and is an higher octane liquid thus it needs less spark to ignite this is why it starts things that are hard to start.
Also another thing to consider is when you increase compression you need to look at fuel octane ratings the higher the compression the higher the octane in the fuel needs to be, if your getting up there in the compression stakes you may need to look at 100+ octane fuel (BP100)

_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[NeKeleC]

TRX435 wrote

Quote:

i'm limited to they type of plug only denso make an iridium for the 400 ex

I find this hard to believe as the plug i have told you about most motorcycle shops will tell you they don't exist (it was the plug Mick Doohan used in is GP bike) but all i had to do was give repco the part number ngk gave me and they special ordered it for me from ngk. You need to give NGK aust a ring if you want to go down that path, tell them the standard plug number and what it's out of and they will give you a replacement plug number then go to repco get them to order it for you.

Also the plug you are using (xr600 plug) is it the same temp as the plug for your bike, also all plugs have different spark charicteristics so the xr plug might not suit the 400 motor. Is the 400 motor based around the xr 400?? might be better using plug out of xr400??

a bit of info i just found

MSD Enhancer Ignition for the Honda TRX400EX Installation Instruction
Short Description
Spark Output: The Enhancer Ignition System for the Honda 400EX produces a high output spark that is approximately double the stock spark output. This increased spark energy allows the use of richer fuel mixtures or even exotic fuel such as alcohol. The MSD Ignition will put out approximately 30,000 volts to the spark plug.
A good rule of thumb for the spark plug gap is between .032� and .036"

[/quote]
_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[NeKeleC]

Also just searched trx400 spark plug and found

Honda TRX 400 EX6 06-08 Spark Plug NGK Iridium
plug no DPR8EIX-9

So who ever told you they don't make them i wouldn't shop there again as they obviously have very limited knowledge about motorcycles or the internet in general.
Sorry i just can't stand bike shops that feed customers s%#t instead of helping them out.
_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[cuzo]

Ill check the gap when I get home from work, and pick up some new fuel,
_________________
04 Polaris Predator 500 with mods
ProArmor - Revolution nerfs

[crx450r]

the DPR8EIX-9 is the plug if got
the standard plug is a DPR8Z
the iridium plug has a larger gap and is 1.5 mm shorter
i got the plug number off the thumper talk forum the xr 400 owners in the us use them and adjusted the gap to suit
i like the msd ignition but don't know if the $700 price tag is worth it

[NeKeleC]

Well you've the right plug and you're standard ignition is ok. Give NGK Aust a call regarding a higher voltage plug $40 for a better plug rather than $700 for an ignition may give you what you need it's worth a try.

Wih your head gasket issue check torque settings on the head you may need to go slightly firmer than standard as you are using high compression piston and use a metal style gasket if you aren't already.
And with your original question about burning out plugs there is still an underlying issue there when you get bike back running check plug colour it should be medium brown in colour too light brown or grey in colour bike is running too lean this will burn out plugs and eventually the top of your piston. If the bike is jetted a little bit rich (medium to dark brown) and has good air flow you will find it will pull better through corners and up hills anyway.
_________________
The main thing is to have fun I just think second place is no fun

Me - 09 Quadracer 450R No 339
Mrs -09 Quadracer 450R No K77

[crx450r]

i've just ordered a new cometic triple layer steel head gasket,
crf450 timing chain, new k&n air filter and ported and polished the head so ill have to replace the needle in the carby anyway for more fuel

[HaggLE]

If the iridium plug mentioned earlier is correct, it is saying that a gap of 0.9mm is what will be supplied. The number after the "-" in ngk plug numbers is the gap in tenths of a milimetre I.e. 7 is 0.7mm, 11 is 1.1mm

[crx450r]

i made the gap smaller
used the plug for 5 weeks and it's still in perfect condition no fouling
so it seems to last longer so far