Iridium Plugs - Ducks nuts or Utter rubbish

[alexbrown64]

I use DENSO now that last forever Doc not those NGK shitters that come fautly out of the box. Well down Eastren Creeks long straight half a HP is enough to break the tow, enough to repass if you pull a desparate up the inside to turn 2 and enough to pull out of your draft and motor past onto the straight. What a dyno won't show is throttle response, which with a race plug,is off the scale. I've converted enough skeptical tightarse trail bike riders and the phase "I didn't know a plug could make so much difference" is always used. 
But you all keep using those $5 jobbies

Old thread but i thought that i would report that nothing has changed.  I just had to push my bike through the bush and back to the car.  New NGK Iridium plug with 30 minutes on it just died.  Put a new plug in and all good.  Have ordered a Denso Iridium as cant trust those NGK now.  Bike is running a PVL ignition.
Cheers,
Alex

[KTM47]

I had a PVL ignition on my Maico. When I fitted it I recall the paperwork from PVL said don't use a iridium plug and use the plug cap provided.   

I use a NGK B9EGV the same plug I used in 1976.

[DR500]

1976? about time you brought a new one

[alexbrown64]

KTM, the instructions that came with mine recommend a fine wire plug to help starting.

"It is important to select plugs with fine wire or precious metal center electrode such as gold, platinum, or irid
ium. The smaller or finer the center electrode of the spark plug is, the less energy it takes to create spark to start your engine. Large center
electrode plugs require more of the ignitions current to make spark and will cause starting difficulties, especially open class engines."

http://www.pentonracingproducts.com/pvl-ignitions.shtml

Cheers,
Alex

[KTM47]

1976? about time you brought a new one

What I was saying is. Not the same plug but the same type of plug.  NGK stopped making the BEGV type plugs but they are making them again.  So it makes sense to use the same type of plug we used when the bikes were new.  Also the BEGV type plugs are sold as a racing/competition plug and priced accordingly.  They are distributed in Australia by McLeods.

[80-85 husky]

my old kato 250 (2000 model) protested the use of a stock plug by breaking down at the top end...took me awhile to figure it out. needed a racing plug to keep pumping up top.

was cleanly jetted but would foul a plug on cold if you went past the needle jet too soon. had to work your way through the blubbery bit till she cleaned out.

[Daryl Jones]

Mention of the BEGV reminded me of a strange problem we had with these plugs.

In the early-mid 80's my brother and I rode a lot of club level Enduros & Pony Expresses.

We had air-cooled PE's & KDX's and used the BEGV plugs. The bikes usually ran well on them.

EXCEPT after long, slow, technical, creek crossings. Opening the throttle on the way out often stalled the bikes dead.


At that point you had a few possible options:

a) You could furiously kick the bike over dozens & dozens of times until it finally started or you wanted to throw up or both.

b) You could park the bike up, get out the plug spanner and pull the plug, look at it, blow on it and put it back in.

c) You could sit quietly on the bike, in a cloud of rising steam, for a couple of minutes, until temperatures stabilised.

They all took about the same time, c) was the easiest, except for watching all the XR Honda's you had passed, passing you back.


NEVER had the problem using standard type BPES and used them all the time after that.

"Best" theory was that the fine centre electrode had less 'mass" than the standard one and was "chilling off" quicker, stopping it from firing effectively.

Operating the choke 1/2 way across showed some promise, but was pretty awkward, and definitely risked wetting the plug.
Using the standard type plugs was much easier.
 
Did any-one else have similar experiences?

Cheers, Daryl.

[KTM47]

Simple. If you are racing use a race plug. If you are trail riding use the plug that doesn't foul when going slow.

[Lozza]

what happens to an ES plug in an engine properly tuned. Thick electrode shatters the porcelin first and over heats quickly after that

[Daryl Jones]

"what happens to an ES plug in an engine properly tuned".

As we have discussed and agreed before:
There's LOTS of difference between top level road-race engines and vintage PE175's (or TS185's).

But, as this is a Vintage Forum, we need to consider those types of machines and their practicalities as well.
How would the NSR respond to the thermal shock of being ridden into and submerged in a creek at full race temperature and then be forced to drag it's arse back to full speed immediately after?

It's not my place to recommend anything to any-one, let alone insist on it.
I just reported my experience to see if anyone else had experienced something similar.
Cheers, DJ

[sleepy]

I go along with Daryl here and say that for 99% of VMX bikes the stock old NGK xxES or the Nippon Denso xxxES-U will work just fine provided your tune is correct and you can afford to keep a few spares in the toolbox.

The photo above in my opinion shows the wrong heat range or a poorly tuned engine or both.

Another thing to watch out for with NGK plugs is the big "R" on the box doesn't mean Racing it is for Resistor plugs that need to be steered clear of for most vintage bikes.

[80-85 husky]

apart from my old Gemini 80 when I wuz a nubee to all things bikes, I never had a plug issue when racing. my PE 250 had the original plug in it until it wound itself out and flew down the highway(found it, dusted it off and it got me to a shop where I bought a newy). the kdx I put a new plug in it before an event (for something to do) and it was a dud out of the box? so the original went right back in.

the wr husky had the same plug in it after 3 years of riding (I replaced it with the piston and rings..)

I allus got a Mr Mc Hanic to jet the bike out of the box after a brief run in and de restrict. im sure that helped

[GMC]

This may not be the case but it is worth considering.
There are a lot of fake brand name components in the car industry that are causing good mechanics a lot of diagnostic headaches and even some good suppliers have been caught out.

[bigk]

I've had drama's with NGK "ES" series plugs, they seem to either work forever or not at all. I now use "EG" series plugs and have had no problems. I found some NOS B7EM (twin electrode) & use them in my modern bike which specify a 7 heat range. I also steer away from resistor plugs in all bikes & jet skis.
K

[alexbrown64]

With the advent of the internet, these fake items going around have flourished.  Perhaps that is the reason i had an NGK iridium plug failure after just 30 minutes and others have had them fail out of the box.  Hope the Denso iridium IW27 i just purchased online isnt a fake.