I bought 4 spark plugs from a local motorcycle shop, I asked for DR8EA's but when I got home they were DPR8EA-9's. I called the shop, they say exact same plug, just the tip is 1MM longer. I am a little skeptical right now, will the piston smack the plug, is the clearance that tight?
If I'm not mistaken the 9 at the end is not to do with its heat range and the plug is no longer than the other plug but the projection of the tip is exposed more resulting in better fire.
Correction the 9 stands for 0.9mm (.036”) it's a wide plug gap.... And the P stands for projection.
Tony's got it, the 9 at the end indicates a .9mm gap, which is WIDE. It might be ok if you're keeping rpms below 5000, but at higher r's it's going to misfire. Personally, I close all my plugs down to .025" and have no high rpm misfire issues. Steve
My dr8ea plugs were all over the place from the factory. I gapped them all to .025". It takes a few seconds to check. Why not do it?
I would at least check them. I know mine are standard and yours are iridium, but why not take 45 seconda and check?
Yes, I'm gonna pull the plugs just as soon as I've got through the current tank of gas. As we all know, it's a PITA to take the gas tank off when it's full due to the bloody weight