Topic: Spark plugs-CB750K

[Cincycaddy]

I just picked up a '75 CB750K and was wanting to pull and check the plugs.

My first issue is getting the center 2 out, since I don't have the oem tool kit.  My second issue is that the plugs that are in there now are Champions with a 16mm head on them, and from reading through the FAQ section they should be a 18mm no?  I am NEW to motorcycles, all together, so I have a bit of a learning curve.

Chris.

[Bob Wessner]

There just happened to be a recent thread on this, check it out..

http://www.sohc4.us/forums/index.php?topic=5624.0

[Cincycaddy]

Thanks, turns out, the PO had left NGK D8EA's in the inner two cylinders and installd Champion RA8HHC's in the outer ones. So I was trying to remove a 18mm NGK with a 16mm socket, silly me for thinking they were the same in all cylinders 

Well, thats part of the fun right?  LOL  Two things figured out now, when i got it the tailights weren't working, shoddy wiring from the seat to the Honda wiring, solder, heat shring and a modified trailer harness plug for disconnect and thats working again.

Thanks for the link,

Chris.

[jdpas29]

put D8EAs back in all the cylinders.  they are a good spark plug.  i've heard some bad things about the champs in these bikes although i love them in other applications.

[Cincycaddy]

NGK's, ok cool. I ran and got some of the Champions as that is all Autozone had.  I'll source some NGK's and put those back in there then.  These things should be gapped at .025? The plugs I pulled out were gapped near if not a shade less than .020.  The old plugs were quite dark, so I guess I can assume she is running rich.

Chris.

[Bob Wessner]

Thanks, turns out, the PO had left NGK D8EA's in the inner two cylinders and installed Champion RA8HHC's in the outer ones.

I regularly swore at my PO while trying to get my 750 back on the road. I've since gotten a bit more philosophical about it, after all I'll be someones PO some day I guess.