Spark Plugs

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saber
Posts: 40
Joined: Thu Jan 31, 2013 6:46 pm

Spark Plugs

Postby saber » Mon Nov 25, 2013 9:31 am

Hi all,
I have a question about spark plugs. My 1979 CB650 has D8EA NGK plugs with about 800 miles on them. I live in Pennsylvania and plan to ride all winter which I have not done before. The owners manual mentions that D7EA NGK plugs should be used if temperatures are normally under 41 degrees F.
My question is how D8EA and D7EA plugs differ? Why does Honda recommend different plugs in the colder weather?
Thanks, Saber

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Spark Plugs

Postby my79650 » Mon Nov 25, 2013 11:24 am

The difference is the lower number. Means it will start and run easier to a certain temperature drop. Not sure exactly the specifics but make sure all your electrical is working properly. If i'm wrong then someone will correct me.

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Volker_P
Posts: 5508
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Spark Plugs

Postby Volker_P » Tue Nov 26, 2013 3:53 am

Hotter plugs (lower numbers) differ by a lower heat transport away from the electrode to the plug socket.
This makes them reach operating temperatures at colder operating conditions as typically in winter (colder engine, but moreover shorter trips and lower rpm).

When I did still ride in winter, I did not change the plugs. However after the first extended turn at some rpm in spring, I got a completely different engine again. I adressed it to the plugs burning free again from all that winter tortures.
So hotter plugs might be worth it although you usually don't need the power in winter anyway.

But don't forget to swap back in spring!
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

saber
Posts: 40
Joined: Thu Jan 31, 2013 6:46 pm

Re: Spark Plugs

Postby saber » Tue Nov 26, 2013 10:57 am

Thanks MY79650 and Volker,

I think I will go with the lower numbered plugs. My #1 cylinder seems to be firing now and then and the plug seems to be dark with a gas smell. It stays cold long after the other cylinders heat up ( touching pipes ), but when I return from my ride to work of 9 miles, the pipe is really hot. Would the hotter plugs help this situation. Thank you,
Saber

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Volker_P
Posts: 5508
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Spark Plugs

Postby Volker_P » Wed Nov 27, 2013 3:12 am

As the others seem to run from the beginning on:
If it was not a plug#1 problem probably not.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

saber
Posts: 40
Joined: Thu Jan 31, 2013 6:46 pm

Re: Spark Plugs

Postby saber » Wed Nov 27, 2013 9:39 am

Thanks, was hoping for the easy way out.


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