I need to replace my NGK C7HSA spark plug and would to know if it would be worth it to switch to the NGK Iridium high performance plug? If so what is the plug number so I know witch one to get. I own a new SL-150-21B scooter. Please help me with this issue!!!!! P.S. You don't have the SunL make or my model on or website so i just put down Kymco as Make and Grand King as the model.

NGK Iridium IX - 7243 (4.0L)
NGK Iridium IX - 7397 (3.0L)
NGK Iridium IX - 7164 (2.3L)

i have 68 camaro with orginal sbc 350 and if you want to run a high dollar iridium ngk plug you would want the this one. NGK (7355) XR5IX Iridium IX. Honestly its a waste of money though a good copper core plug is much cheaper and the park is just as hot you will gain nothing from the high dollar plug performance wise. it may last a little bit longer but at the price of $6-8+ each they are not worth it when you can buy any name brand solid copper core plug for like $2 each and gap the plug make it a little hotter and your good to go!

Virtually the entire motor trade is in favour of NGK spark plugs, the parent company of which is Nippon Denso, original equipment on many Asian built vehicles.

I would definitely go with an iridium plug offered by NGK for the most complete combustion which increases engine efficiency, fuel efficiency, and power. The part number for an NGK iridium spark plug for a Yamaha dragstar is DPR7EIX-9. These are a bit more expensive at around $7 but are absolutely worth spending the extra money as they are proven to last significantly longer. If cost is a factor, a regular ngk spark plug is around $2 and would be part # DPR7EA-9. I hope I've answered your question satisfactorily and ask for you to take a moment to rate my answer. Thank you, Jim. NGK 7803 DPR7EIX 9 Iridium IX Spark Plug Pack of 1

NGK 5129 DPR7EA 9 Standard Spark Plug Pack of 1

You can easily look this up on line at the NGK sparkplug site. Global Denso also has the info for cars and motorcycles. (The OEM sparkplug for your bike is either NGK or Denso... upgrade with Iridium Plugs for a bit more HP and longer life.) It's 0.035" The iridium Denso Plug is 5375 (IX22B)

NGK Part # 5044 {#1262, 4525, 6824, 7051, B8EV, B8EVX, BR8EIX, BR8EVX} Iridium; Iridium IX
750 Model; T140V; Gap .024 CHAMPION Part # 88091 More Info {#8809, 88092}
.036 Good luck, Bill

check Gap: .040

Bosch Spark Plug: Part Number: 18594-05120685

PLATINUM -- Original Equipment is Iridium. Gap is Preset

OE Fine Wire Platinum -- Do Not Gap, Gap is Preset

OE Fine Wire Iridium -- Do Not Gap, Gap is Preset

Description:
V-Power Plug, 14mm Thread Size, 26.5mm (1.04") Reach, 5/8" (16mm) Hex Size, Gasket Seat, Resistor, Projected Tip, Solid Terminal Nut, V-Power (V-Grooved Center Electrode), .043" (1.1mm) Gap, Heat Range 5

To purchase:
http://www.ngk.com/results_cross.asp?pid=LFR5A-11

or here...
http://autoparts.greencarreports.com/auto-part/ngk-6376--ngk-6376-lfr5a-11-v-power-spark-plug-pack-of-1

cross to a Denso;..
http://autoparts.greencarreports.com/auto-part/denso-5343--denso-5343-ikh16-iridium-spark-plug-pack-of-1
or
http://autoparts.greencarreports.com/auto-part/denso-3417--denso-3417-sk16hr11-iridium-long-life-spark-plug-pack-of-1
or just a standard NGK #...
http://autoparts.greencarreports.com/auto-part/ngk-5018--ngk-5018-spark-plug
And last but not least:...

For maximum performance, at a premium price, you can use NGK Iridium # 4469 (LFR5AIX-11).

For longest life, with a bit less performance, at a premium price, you can use NGK Iridium # 6240 (PLFR5A-11).

The best value in plugs for this motor is Autolite Iridium # XP5325. It costs about 30% less than the NGK equivalent, and runs just as good.

These plugs come pre-gapped at .044" (1.1mm) which is the right gap for this motor.

It depends on who you think is smarter. The people who designed the vehicle's engine or the guy behind the counter at Auto Zone.

I would go with the people who designed it because they did all the testing to come up with the spark plug needed which is an NGK PLFR5A-11.

Don't lose focus on what a spark plug does. You will not gain any performance from a iridium spark plug. Iridium is the design of the electrode center. You're just spend more money if you're not producing some killer heat in the cylinder which a 2.5 will not.