The NGK Iridium IX Spark Plugs utilise a 0.6mm laser welded fine iridium tip which ensures high durability and a consistently stable spark along with a tapered ground electrode which minimizes electrical quenching effect. The longer insulator nose prevents fouling, the corrugated ribs on the insulator prevent flashover and a triple gasket seal eliminates combustion gas leakage. you will notice in the first picture by -AK- you can see the spark plug throat, that is the electrode and ceramic insulator and then space between the threaded material and the electrode/ceramic insulator. How far up inside the spark plug does that space go? A typical copper spark plug will last around 20,000 miles and most get changed at a major service (usually around 16,000 miles) but an iridium spark plug will be good for around 50,000 miles and you do see people running them to 100,000 miles with no issues. NGK is the brand leader in the UK spark plug market and are the world's biggest supplier to many major car manufacturers. Each and every one of their products are designed to meet the most rigorous standards and are the professionals' choice because of their quality and technical excellence. Their plugs can be found in use by teams in F1, WRC and MotoGP. Put simply, NGK genuine spark plugs are the workhorse at the heart of smooth-running engines around the world. however, if the plug is too hot, the material of the electrode or the ground tab will soften, distort, or even oxidize.

Harley Davidson Spark Plug Cross Reference - Biker Rated Harley Davidson Spark Plug Cross Reference - Biker Rated

Maybe it's time for a little spark plug 101 as it was explained to me by a guy who didn't spout any BS.

Kawasaki Spark Plug Fitment Chart

If the engine is running dangerously lean the whole plug tip will be grey or white. If the temperature is over 850-degrees, pre-ignition may occur. Engine power will be reduced and you risk piston damage. so the uber smart engineers calculate that heat transfer path, the average temp for the engine at full throttle and full load, and at idle... proposed engine coolent temp limits and toss in 20% safety margin and then design a plug that will hold self cleaning temps over the widest range of engine RPM, ambient temp, etc. with out ever reaching "burn out" temp and volia' you have a plug for your specific engine. Fake plugs are known to have air bubbles trapped inside the white ceramic insulator which can affect heat dissipation capability.

Spark Plug NGK Iridium CR9EIX vs CR9EIA-9 - Kawasaki ZX-10R Forum Spark Plug NGK Iridium CR9EIX vs CR9EIA-9 - Kawasaki ZX-10R Forum

A spark plug electrode is litterally at the absolute hottest part of the engine. It is where combustion starts, when compression is the highest it's going to be, and where a lightening bolt (that is a plasma discharge) is purposfully formed. A spark plug fouls with every single power stroke of the engine, as the fuel burns a deposit of soot forms on the electrode. Form enough deposit, the gap resistance changes and the plug either is resisted out or shorted out, neither of which will fire the cylinder.The fakes terminal cap shape is pretty accurate, however cast mold lines are visible, unlike the genuine plug. As stated above, the illustrations on the rear show installation procedures for an M14 threaded spark plug. Unfortunately for Mr Counterfeit, CR9EIX spark plugs have an M10 sized thread! This fatal error has already fulfilled our suspicions that they’re indeed fake, and we haven’t even seen the plugs yet! This nifty little tool only costs a few quid and will help you set the correct gap for your spark plug. However, modern plugs are almost all motorcycle-specific fit and so they come ‘pre-gapped’ and you won’t need to touch them. If you’re running a classic bike, you’ll probably need to set your gap and if your bike’s not running right, a gap tool can help you rule out a potential incorrect gap issue.

Kawasaki Spark Plug Fitment Chart - Biker Rated Kawasaki Spark Plug Fitment Chart - Biker Rated

This is why you can't 1. hurt your engine with the wrong plugs... you can only hurt your plugs. and 2. Plug slection has no affect on engine performance or horse power... If your plug is fireing during every power stroke... that's the best it can do. Fatter spark, bigger spark, super jiggy spark Doesn't matter... if the fuel/air mix is being ignited every time... that's as good as it gets. Mind you, there are 1000 things that can mess with "fireing every power stroke" but you won't get more power using a "hotter" plug. Designed specifically for the performance enthusiast Iridium IX offers extreme ignitability, improved throttle response and superior anti fouling. The fakes terminal caps were finger tight, whereas the genuine caps couldn’t be undone by hand and needed pliers.The image of the spark plugs above shows four common conditions that you’ll find your spark plugs in. From left to right the plugs are Normal, Rich, Lean and Very Lean. Full descriptions below.