sparkplug differences

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mlhend1

Member
Apr 17, 2002
186
0
Is there a dramatic difference in the range in sparkplugs, for example, between a NGK br9eg and br8eg. If the sparkplug is slightly wet and black with a br9eg what more likely would it appear (golden brown?) with a br8eg? Does anyone use a br7eg?
 
M

mlhend1

Member
Apr 17, 2002
186
0
When temperatures change a great deal from morning to evening I find myself having to adjust the airscrew to avoid becoming rich when going through tight/slower trails. I'm running a br8eg plug, but have thought of running a br7eg during cooler parts of the season. Is this a good idea?
 
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fuzzy

~SPONSOR~
Jul 26, 2002
447
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Switching to a hotter plug can be useful as a temporary fix for jetting problems, but the REAL fix is to jet the bike properly and run the factory recommended plug. Hotter plugs will result in higher operating temperature.
 
C

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
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re: dramatic diff?

Up to 100º diff.........centigrade according to ngk.

'7' range plugs are commonly used. It's easier than curing the problem (as fuzzy said).

It's also hugely less effective.


But then, bandaid approaches usually are.


BTW...AS adjustment to compensate for temp changes is normal. That issue doesn't relate to spark plug heat range selection.
 
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canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
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Depends on the model/make/year of your bike. It will be in your manual. Some kdxs use nines, some eights as oem configuration.

Re: 'H' models (late model kdxs) are spec'd at '8's. An NGK tech told me, 'The '8' range was chosen for the kdx for a reason. It's the right plug.'

This is not to say that different ranges than spec are always bad. BUT...like fuzzy said it is often an excuse for being too lazy to jet a bike correctly.

...something I've been guilty of more'n a few times for sure.
 
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rethnal

~SPONSOR~
Jul 14, 2002
659
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I have never ran anything other than the factory specified plug.... if you are fouling... it's not the plugs fault! I have found it is ALWAYS something else... i.e jetting, timing...something! But, it is always a good idea to change your plug at least once a season.... plugs deteriorate just like anything, however so slight. At $2 a pop... who cares! :)
 
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fuzzy

~SPONSOR~
Jul 26, 2002
447
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The IX plugs are sweet, but don't spend money on them until you can put MANY TANKS through your bike w/ a regular old ES. IE Only switch to one wonce your jetting is right.

This is not to say that different ranges than spec are always bad. BUT...like fuzzy said it is often an excuse for being too lazy to jet a bike correctly.
Click to expand...

Or when your endlessly searching local shops for a jet to no avail and you're riding the next day....LOL My case this past weekend. The WR's pilot is sinfully rich, ran a 7 all day and at least it didn't foul. It would foul an 8 pretty quick. Removed carb to check jet size...Broken screw holding the bowl...LOL Just got this thing and it needs some TLC.....The KDX always stays ready to rock....
 
K

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
0
how do the numbers differ? 8 is standard on my bike, and I have a NGK BR9 in there. The dealer says its a racing plug? Is it the higher the number, the hotter, or the lower the number? thanx
 
K

KDXFreestyle

Damn Yankees
Member
Nov 19, 2002
645
0
Brockton cycle, in Mass. So is this a raicng plug? the difference is the little thing that stickes out is WAY skinnier. is he telling me bull or what? I noticed it runs good though.
 
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rethnal

~SPONSOR~
Jul 14, 2002
659
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There is no "Racing plug" There is only right or wrong. 8 burns hotter if that's what you mean but if your bike calls for a 8... use an 8, if a 9 then use a 9. Running a hotter plug just means higher operating temperatures meaning more heat which is not a good thing on your motor. Yeah.... you need to find a better dealer or maybe he is just trying to save your bike from you. :)
 
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S

skipro3

Mod Ban
Dec 14, 2002
902
0
An NGK tech told me, 'The '8' range was chosen for the kdx for a reason. It's the right plug.'
Click to expand...
If this is true then what jetting is the NGK tech basing this on???? With stock jetting, my KDX220 is wwwwayyyyy to rich. Once I got the jetting right, ran about 35 degrees warmer.
 
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rethnal

~SPONSOR~
Jul 14, 2002
659
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So you think that 35 degrees cooler is the right temp? Where did you get the data for that?
 
M

mlhend1

Member
Apr 17, 2002
186
0
How about 2 cycle oils that have higher flash points and don't completely burn with a conventional b9es plug and leaves "sponge" behind. Some oils made for racing and extreme conditions don't break down completely under more "mild" riding conditions. I'm also tired of adjusting my air screw everytime the humidity and/or temperture changes significantly. Since I have moved to a hotter br8eg plug I haven't had to do this to get the "golden brown" plug I want in almost any condition.
 

Jackpiner57

~SPONSOR~
Aug 11, 2002
356
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KDXFreestyle, Use the BR8ES as recommended in the manual, then jet it so the bike runs right and the plug looks right.

Why did you go to a BR9?

I grew up in N. Easton, but have no experience with Brockton Cycle. It sounds like whoever you talked to did not give you the best advice.

What oil are you using and at what ratio? :think:
 
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rethnal

~SPONSOR~
Jul 14, 2002
659
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The thing is... you don't want it to burn completely... If you think so... then what is lubricating your top end? Words to think about....
 
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skipro3

Mod Ban
Dec 14, 2002
902
0
The top end is lubricated on the intake stroke, as the fuel/oil mix is sucked into the lower case as the piston is on it's upstroke. This is lubing the crank and wristpin as well as the cylinder walls. After going through the ports and pushed into the combustion chamber, it is now burned. You don't need to lubricate the combustion chamber. As far a engine temp. is concerned, I am basing my ideas on using a thermal imaging of mine and other KDX's at the local track. I've access to a hand held digital thermal reader that you just point at the object you want the temperature of. My bike runs 25 to 35 degrees warmer. This may be due to the fact that my bike is a 220 and the other KDX was 200. I've heard 220's run warmer but I've not found any data on this. Also, my bike is warmer after jetting correctly.
 
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rethnal

~SPONSOR~
Jul 14, 2002
659
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I've heard the 220's run warmer too...Wonder why that is? I don't think 25 to 35 degrees are going to make that much of a difference unless you are pinning it all the time as sometimes I do getting through the muck. I guess it would be something to watch.
 
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fuzzy

~SPONSOR~
Jul 26, 2002
447
0
bR9es. R is for Racing....LOL

This is probably what your dealer thinks as I've heard this before. R stands for Resistor. R type plugs are specified for use in KDX's due to the lighting equipment.
 
M

mlhend1

Member
Apr 17, 2002
186
0
Isn't complete burning of fuel the whole idea? The 2 cycle oil lubricates the cyclinder as its being pulled into it to be compressed. Incomplete burning lends iitself to spark plug fouling, carburator gumming and "sponge" throughout the engine/pipe. The more complete the fuel is burned the "more bang for the buck" (power).
 
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