Motorcycle Repair: HONDA 1973 CB350, denso plug, heat range

Question
Hi Bill
      I would like to thank you for the help on my cb 350 miss and hard start.
As you said spark.It so happen that the was sparking not on the tip but from the insulator.
So i used another plug and all kind of spark .
Now my problem is the plugs that are in are DENSO W24EP-U but my parts bike has ngk b-7es.
Looks nothing the same what plug works best.The denso plug has 600 mile on it and looks black but not wet or oiled and the right gap would be
THANK YOU AGAIN  BRAD

Answer
Brad, the stock NGK plug is a B8ES or ND W24ES. The W24EP-U plug you have features an extended tip and U-channel side electrode.

IF your plug was fouled on the insulator, then you still need to find out why it did that. Check timing, idle speed mixture, syncronization, float levels, etc..

Either plug of the right heat range should work fine if your ignition system is in good shape. The B7 is one heat range too hot...

Bill Silver