Honda Ignition Zener Diodes for CB600 CBR900 CR250 and others
After tracing down a no spark condition to the ignition switch I found this Zener diode to be the root of the issue. I had replaced the ignition switch with another purchased online that did not contain it. The Honda ignition switch contains this Zener diode as an anti-theft device to kill the ignition system at the ecu preventing spark and fuel.
I kept my aftermarket ignition switch, traced the wiring back to the ecu and installed my diode. I put it on the pink wire from the ecu with the diode pointing toward the ignition switch. The “block” is from the ignition to the ecu.
Here’s another visual of this zener in action and how it is preventing current flow, that is until it hits the breakover voltage. To learn more about zener diodes I recommend visiting this article from the university of Oklahoma. https://www.nhn.ou.edu/~bumm/ELAB/Lect_Notes/diodes_lecture_v1_2_2.html
I have these 500mW DO-35 Zener Diodes for sale. If you need them, see: https://ebay.us/C1BAtw
Here is the list I have of known bikes these work with but I suspect there are more. If you have one to add, let me know and I will add it.
1990 Honda CBR600F
1989 Honda CBR600F
1988 Honda CBR600F
1987 Honda CBR600F
1994 Honda CBR600F2
1993 Honda CBR600F2
1992 Honda CBR600F2
1991 Honda CBR600F2
1998 Honda CBR600F3
1997 Honda CBR600F3
1996 Honda CBR600F3
1995 Honda CBR600F3
1999 Honda CBR600F4
2000 Honda CBR900RR
1999 Honda CBR900RR
1998 Honda CBR900RR
1997 Honda CBR900RR
1996 Honda CBR900RR
1995 Honda CBR900RR
1994 Honda CBR900RR
1993 Honda CBR900RR
1992 Honda CBR900RR
1997 Honda CR250
2007 Honda CR250R
2006 Honda CR250R
2005 Honda CR250R
2004 Honda CR250R
2003 Honda CR250R
2002 Honda CR250R
2001 Honda CR250R
2000 Honda CR250R
1999 Honda CR250R
1998 Honda CR250R
1997 Honda CR250R
1996 Honda CR250R
1995 Honda CR250R
1994 Honda CR250R
1993 Honda CR250R
1992 Honda CR250R
