by the way, they are both the platium iridium (spelling) plugs

 

the ''extended high speed riding'' (NGK-IFR8H11) plug is a colder plug......for when the engine will be running at higher temperatures than normal.......this is the plug that I run all the time in mine.....

the standard plug is the NGK-IFR7L11

 

The high speed riding plug is actually colder - meaning it will transfer more heat from the spark plug to the head.

Only consider this plug if you have a special application for your 450R - like extended high engine speed racing (lots of top speed operation).

 

this cuts back on engine heat. due to extended high speed operation.

Bobby

 

this cuts back on engine heat. due to extended high speed operation.

Bobby

 

You say extended high speed, so are you saying it would be better for like tt and not much benefit for xc, or would both see a benefit.

 

Well I do alot of fast trail riding. I don't spend all of my time in the upper rpm range. I use the entire band range and like to very my riding style throughout the day. Should I use the normal or extended higher range plug? I just changed to the extended high range plug (just found that out) this week and will not be able to tell the difference in plugs until this spring when I hit the trails. All I can do now is ride around in the driveway because I can't ride on the snowmobile trails that run right through my back yard. :banghead:

 

special application for your 450R - like extended high engine speed racing (lots of top speed operation).[/b]

thats me right there. im gonna have to get one of those :thumbsup: . had my first race yesterday and most of it was spent in 4-5 gear, id say over 74% of the desert was spent in that. the bike ran real good. and i did wayyy better than i thought. i was in 10th overall out of 60 quads oh4: and i was in the beginner class. next race im going into novice it was 10 laps of 15 mile loops

 

I aint no plug expert.....but ive been racing almost every type of vehicle you can ride for the past 30+ years....

and here is what I have found out thru experience...

so far..... and I mean SO FAR.... I have not found any single reason why a person should NOT run a cooler plug.... Cooler meaning its designed for high speed operation.....(NGK = larger number... )

I have been 'told' by many that a cooler plug will foul easier and be harder to start...... makes sense right? WRONG...

the ability for electricity to jump the gap of the plug is by now way measured by the cooling effect of the plug..... you can put a stock #7 heat range plug in your 06....and it will start no better than if you had a #25 heat range plug.....(no, they dont go that high...just a figure of speech)......

now....the 'fouling' ability of a plug.... yes...a 'hotter' plug can help reduce fouling of a plug......however, in a 4-stroke...I have NEVER noticed this to be an issue.....in some 2-strokes...yes... due to high oil consuming ratios....and the mere fact that a 2-stroke is a very 'wasteful' engine.....there is a chance a colder plug may foul out sooner..... but I have NEVER actually SEEN this in a 4-stroke....

I have been running the IFR9H-11 in my bike since after the first month I have owned it......I fouled out ONE plug...... but amazingly enough this same plug worked just an hour later (go figure)......and I have been running this same plug for the past year + at least.........from what I have been told....this is the coldest commercially available plug for our machines.....#9..... but, it works great.....I ride TT, Drag Race, Dune, Trail ride, etc.....and with Nitrous use....I would use no other plug....


take it for what it's worth.....Colder is Better (for 4-strokes)..IMHO......Greg

 

hmmm, Greg, I may have to try a "9" plug, even though my "8" has been working just fine and in the 3 years I've owned it, I'm on my second plug; and it was changed just because I was there and figured it might not hurt to change a plug that is a year-and-a-half old.

 

awesome greg, now i need to go get one at my dealer and replace it before my next race. or replace it just because

 

the only thing I could never get a straight answer on from NGK themselves.....

was the difference between the H series....(04/05).....

and the L series....(06/07).....

but heck....I run the IFR9H-11.....and its been working great after 1 1/2 years.....

I dont think a standard tipped plug would have lasted that long under heave nitrous use......Iridium is tough to beat....

Greg

 

I have a question, I think I have the normal stock plug in right now. The temps here are highs around thirty right now. Will the cooler plug still start good in those temps? The only reason I am thinking of switching is because of all the muddy conditions we are having in the races and the problems with overheating.(I know the radiator is the main prob but every little bit might help) Just curious,,,

 

Personally, I'm of the school of though of "if it ain't broke, don't fix it".

Spark plug heat range is a balancing act. Too hot and you're likely to pre-ignite. Too cold and eventually deposits will build up and short the plug. If everything's just right - neither will occur. If neither is occurring, do you really need to monkey with the heat range?

However, if you have a special application that lends itself to a colder plug - like lots of high speed riding (where there's probably more than average heat build up on the tip of the plug), supercharged or nitrous apps (where obviously more heat is going to be generated), etc - then moving toward a colder plug is probably a good idea - which is why it states in the manual to consider the colder plug for extended high speed riding.

Granted four strokes are much more forgiving on things like heat ranges and jetting than two strokes - if you don't have a problem you're trying to solve, why exactly are you messing with it? Especially with plugs that cost ~$10/each. There is no power to be gained from changing plug heat range.

Remember, all the plug's heat range is telling you is how fast the plug transfers heat from the tip to the cylinder head. With that in mind, it can be concluded that heat range does not affect a machine's starting ability - unless of course, you go too cold, deposits short the plug out & you're stuck with a machine that will not run.

Also - FWIW, the iridium plug is less susceptible to fouling than a standard plug. I have personally seen others foul 4 stroke plugs due to poor jetting or starting technique, but have never fouled one myself - now 2 strokes, different story

 

$10 each?

Dang....mine run me $18 each locally.......your 'hooked up'....

 

That's why I put the ~ in front of it :slap:

Seems like I remember finding them for $12 - but then again, I've never had to buy one Although I might consider going to a lower heat range now that I'm running 14:1 in my TT bike