pick Posted February 3, 2008 Share #1 Posted February 3, 2008 Well, damn. Had my tank off so that I could run the GPS wire under it and decided that I had 47k on the bike, figured I'd change plugs. Took out an old one, #2, was an NGK DPR8EIX9 Irridium. Hmmmmmmmmm..... Wonder when these were put in? They looked ok, not really burnt, but what the hey, go to the parts store, they don't have them i stock but can get them by the morning. Kewl, I order. Picked up this morning, read a few posts here, anti-sieze, grease for the caps, man, what a deal! Finish for the night, get out my log to write down al I did and as I am coping the numers, DAMN!!!!!!!!!!!!!!!! Plug numbers are different? Does anyone know wha the difference in an; NGK DPR8EIX9 and an NGK DPR7EIX9 is????????????????? I've already got them gapped and installed.................................. Link to comment Share on other sites More sharing options...
Gone14S Posted February 3, 2008 Share #2 Posted February 3, 2008 Well, damn. Had my tank off so that I could run the GPS wire under it and decided that I had 47k on the bike, figured I'd change plugs. Took out an old one, #2, was an NGK DPR8EIX9 Irridium. Hmmmmmmmmm..... Wonder when these were put in? They looked ok, not really burnt, but what the hey, go to the parts store, they don't have them i stock but can get them by the morning. Kewl, I order. Picked up this morning, read a few posts here, anti-sieze, grease for the caps, man, what a deal! Finish for the night, get out my log to write down al I did and as I am coping the numers, DAMN!!!!!!!!!!!!!!!! Plug numbers are different? Does anyone know wha the difference in an; NGK DPR8EIX9 and an NGK DPR7EIX9 is????????????????? I've already got them gapped and installed.................................. One set of plug's runs hotter than the other I beleave it's the DPR8EIX9. Kurt Link to comment Share on other sites More sharing options...
pick Posted February 3, 2008 Author Share #3 Posted February 3, 2008 Thanks, but I guess I'm asking, is it bad enough I need to take them back or can I run them till my next change? Link to comment Share on other sites More sharing options...
pick Posted February 3, 2008 Author Share #4 Posted February 3, 2008 Well, as it turn out, I searched NGK's site. The plugs that the book calls for are the DPR7, the DPR8 is a hotter plug. Previous owner must have put them in. Just wonder what the performance difference is between and 8 and a 7? Does one range hotter improve anything? Link to comment Share on other sites More sharing options...
rod Posted February 3, 2008 Share #5 Posted February 3, 2008 I would run what you got. At the next change if the plugs are fouled replace with hotter plugs. I doubt there will be a differance. Rod Link to comment Share on other sites More sharing options...
dray Posted February 3, 2008 Share #6 Posted February 3, 2008 your only looking at one heat range dont even worry about it i run a hotter plug in the front cylinder than i do in the back Link to comment Share on other sites More sharing options...
pick Posted February 3, 2008 Author Share #7 Posted February 3, 2008 Thanks al, now Dray, that interesting, because when I pulled my plugs, all were fine except #1 which was slightly wet. All the others appeared normal, tan, dry, not badly corroded. wonder if that might help, running a hotter plug in that cylnder? Link to comment Share on other sites More sharing options...
gibvel Posted February 3, 2008 Share #8 Posted February 3, 2008 By this chart the plug is a COLDER plug not a hotter plug. http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm Sounds like #1 cylinder is getting too much fuel as well. Have you synced the carbs lately? How's it running? Here's an interesting read on spark plug heat ranges: http://www.sparkplugs.com/faqmain.asp Click "Spark plug questions general" then "how do I find a colder or hotter plug?" Then click on "heat range" within the text of the pop up. Link to comment Share on other sites More sharing options...
Eck Posted February 3, 2008 Share #9 Posted February 3, 2008 Pick, If you just happen to shut the ignition key off, just as the #1 cyl began it's "fuel intake stroke" the cylinder could not have fired and thus pulled fuel into the cylinder and your plug may be seem to be a little wet.. I promise you that cylinder IS firing because if it were not, we would not have been able to sync your carbs Friday morning. As for they type plugs you have. I would run the plugs you installed, and not worry about a thing. Believe me, at one heat range (hotter or colder) you wont notice a difference at all. Link to comment Share on other sites More sharing options...
dfitzbiz Posted February 3, 2008 Share #10 Posted February 3, 2008 Pick, I have ran the hotter NGK DPR7EIX9 for about 3000 miles. No difference in performance. Run'em. Fitz Link to comment Share on other sites More sharing options...
KIC Posted July 9, 2012 Share #11 Posted July 9, 2012 So what is the benefit of using a hotter plug versus a stock plug ? Does a "7" do something better than an "8" ? Inquiring minds want to know... Link to comment Share on other sites More sharing options...
OB-1 Posted July 10, 2012 Share #12 Posted July 10, 2012 So what is the benefit of using a hotter plug versus a stock plug ? Does a "7" do something better than an "8" ? Inquiring minds want to know... The 8 should do better than the 7 cuz 8 is a bigger number than 7 and we all know that bigger is better, right? In other words, I don't have a clue... Link to comment Share on other sites More sharing options...
Rick Haywood Posted July 10, 2012 Share #13 Posted July 10, 2012 The Bike calls for NGK DPR8EA-9a The DPR7EA-9A is a hotter plug. I run the 7's in mine and it seems to run just a little better at lower RPM's A hotter plug just means it doesn't dissipate the heat as well as a colder plug. It isn't going to hurt a thing Link to comment Share on other sites More sharing options...
MikeWa Posted July 10, 2012 Share #14 Posted July 10, 2012 We often go up or down one or two heat ranges on plugs. Then read the plug to see where it is at. If the plug is to cold it will tend to foul since a colder plug does not burn off deposits as well. If the plug is to hot it can prematurely wear out electrodes. In extreme cases, more than one heat range, a very hot plug can cause preignition. A very cold can cause excessive fouling. The way a vehicle is driven, ambient temperatures, engine wear, and many other factors can change the ideal spark plug heat range for a given engine. In other words you are probably ok. Next time you change plugs inspect them for the above conditions and adjust accordingly. Mike Link to comment Share on other sites More sharing options...
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