another spark plug question...

[Jarrod]

I was playing around my bike today ( 1977 GS 750 ) and I decided
to order a new set of plugs since I don't have any on hand
so I take a look at what my mechanic buddy installed
when he put my dyna coils and Ignition on and they
are NGK B7ES....
Just curious why those.....I called him and he said
that was what it had in it when he changed them....
any one got any ideas why these instead of the
NGK B8ES ?

thanks

[Dave8338]

Heat range...cooler plug?

[Boondocks]

I was playing around my bike today ( 1977 GS 750 ) and I decided
to order a new set of plugs since I don't have any on hand
so I take a look at what my mechanic buddy installed
when he put my dyna coils and Ignition on and they
are NGK B7ES....
Just curious why those.....I called him and he said
that was what it had in it when he changed them....
any one got any ideas why these instead of the
NGK B8ES ?

thanks

The NGK B7ES is one range hotter than the OEM standard NGK B8ES. The lower the number the hotter the plug. An "8" is at the cold end, as befits an air cooled engine. If an engine is in proper tune but the spark plug is fouling or not burning off carbon deposits, the plug may not be getting hot enough (cold plug) to clean itself. If a plug is too hot, it can melt the center electrode. The standard NGK B8ES will work fine under practically all conditions. If there are extreme conditions, such as the bike being used to ride a few blocks at a time and never warming up properly, there may be a benefit to going to a hotter plug. If an engine is burning oil or the carbs are running rich, someone might have mistakenly put hotter plugs in instead of fixing the underlying problem(s).



See Heat rating and heat rating number.

What do the B7ES plugs look like. The insulator should have a light tan or light gray coating if the heat range is correct.

[Jarrod]

thanks for all of the responses.
When we get ready to install my pods,jets,headers,etc...
I think I will start off with the stock range plug and go from there....
thanks again this site kicks butt!!!!
man these old bikes grow on you........\\/