spark plug gap?

[flamingolodge]

Can anyone tell me what the spark plug gap should be on a GY6 motor? 150cc. I'm using a NGK c7hsa plug. It's a Znen scooter. Thanks for your help.

[tortoise]

To review previous related discussions, scroll down to Google search box at bottom of page and enter . . c7hsa gap.

[kz1000st]

Or .020 to .025 in American.

[JR]

Most standard NGK plugs come gapped at .032 = 8mm and the Iridiums ay .036 = 9mm and here is a manual recommendation by a dealer;

www.gsmotorworks.com/scooter_manual_150cc.html

Other NGK things about gapping;

www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqgap.asp?mode=nml

Some also say never re-gap an Iridium but NGK says it depends;

www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqpregap.asp?mode=nml

Most questions one has can be answered right here;

www.ngksparkplugs.com/tech_support/spark_plugs/faqs/index.asp?mode=nml

I set a standard plug at .032 and I have found that my 250's run better with the Iridium re-set to .032 also. JRR

[speedracer12]

Mine says between 6 and 7 mm so I went with 6.5 which is .025

[JR]

Generally a plug will run OK at that close gap setting but it's not the optimal best and will shorten plug life. Manuals especially one provided in the Chinese scooters are kind of vague and we refer to them as in Chinglish. The Manual I listed was I believe recommended by a shop tech and for me I follow the specs recommended by the maker of the plug because I figure NGK should know more about their plugs than a Chinese scooter manual.

I am also basing my opinion on tests I done this past summer on a 400 mile trip and using different heat plugs and different gap settings and on all of the 3 plugs I tested using the exact same brand gasoline and riding the scooter in the exact same conditions I found the best performance was at the .032 setting even with the factory gapped .036 Iridium. I run a one notch hotter re-gapped to .032 Iridium plug in my 250B and with the sunshine am going to install the exact same in my wife's 250A today! Yea sunshine!

The re-gapped iridium yielded about 3 more MPG in mileage and the scooter starts, idles and runs great. But all scooters are different so what works well in one may not do the same in another. JRR

[speedracer12]

JRR Would that gap be right on a 150 cc without it being an iridium plug? Also does it effect the color of the plug, such as being lighter or darker? Thanks

[JR]

Again there are factors that can change one scooter in one area compared to another as in temp, altitude and even the gasoline one runs. If I really wanted to know my best performance spark plug wise, I would fill up the old tank, try to stay with the same gas if you can, and chart my performance by MPG, and by plug color and how well the scooter ran say over a period of at least two tanks of gas. One can go on a long ride take note of all things and then of course look at the plug and then re-gap it or even chart a like version of an Iridium and by this different settings or plugs find what is the best for your scooter with your riding conditions and your area.

Myself I try to stay in the middle of the spetrum and look for the best MPG I can get and IMO I believe the best MPG one gets is an indicator that you are right on as the plug goes. JRR

[flamingolodge]

Thanks for all the imput guys. When I received my scoot the manual said 0.8 MM, however I don't know if I can trust it or not because there were many recommended fluid weights in the manual that I know are not right.

[flytyer85]

thanks a bunch folks. Will regap tomarrow. Was waiting for the roller weights to get here before we button up the scoots after painting but they are coming from China. On a slow boat ;D ;D I want to ride so I just might put mine together and then I can go, go, go. I'll worry about the weights later. Dog bones to all.