google "9.1 V Zener Diode" in your area,
the diode will need to be put in backwards, the normal way will produce 12v and in reverse, it will limit the voltage to 9.1v. (they are a special type of diode)
Zener Diodes are better than Resisters because they will maintain the 9.1v regardless of the voltage on the battery 10-15v when charging.

 

the Diode was the wrong way around.
9.1 V Zener Diodes

 

Exactly !!! Don't know why everyone shows themselves installing diode BACKWARDS!!!. Then going through all sorts of contortions and hacks trying to get it to work! Just install it properly 1st time around!!!

BTW - voltage rating on zener diode is voltage drop from input, not output voltage. So you want 3.9v drop for 13v. So 13v - 3.9v = 9.1 volt

WRONG!!!


CORRECT!!!


Here’s background on zener diodes and how they work: https://www.circuitbread.com/tutoria...w-does-it-work

Sources for zender diodes, spend the whole $1.00 and buy 10x of them because you’re gonna destroy couple of them installing backwards and overheating them trying to remove. If you think a little for yourself and learn how zener diodes work, you can fix this properly first time around for $0.10 in less than 5-min!

https://www.digikey.com/en/products/...228BTR/1992219

https://www.elexp.com/products/111n7...s-vol-3-9-watt

https://store.synthrotek.com/39V-Zener-Diode_p_877.html

https://juriedengineering.com/produc...ng-temperature

https://www.circuitspecialists.com/1n4730a $0.05/ea !!!

Oh yeah, use one of these and confirm you’ve got 9v at ECU’s pink wire, otherwise you’ve installed zener diode backwards!!!
https://www.harborfreight.com/7-func...ter-63759.html

If it reads (battery voltage)-0.7v you've got it backwards!!!
If you measure (battery voltage)-3.9v, that's correct.
At least you’ll know why it didn’t work instead of just being puzzled and scratching your head…

 

hi all....sorry, new here and going through this problem now on a cb600f hornet in the UK. I have everything working but now stuck with no spark and messing about with diodes and resistors. I can get it to around 10.58v at the pink wire until it's cranked over and then it's 9v.......should it be like that or should it read 9v as soon as you turn it all on?

thanks

 

Should always be 9v. You’ve got regular power-wire connected to pink somewhere. Post photo of how you’ve got diode wired in.


BTW - this guy’s idiot! He’s got diode on BACKWARDS!!!. If he’d measure right after diode, he would see that it barely dropped voltage in that direction 13-0,7=12,3v still way too high. Reversing diode would give 13-5,1=7,9v, way too low.

Take look at this thread on how both regular 13v supply and diode was wired into pink wire. Giving 2 different voltage levels at different times. Post photos and draw diagram of how you’ve got diode wired in.

https://www.600rr.net/threads/2003-c...l-pump.591358/

 

thanks for the reply. this is how the resistor was wired in when I got the bike. I am now using a 3.9v zener diode in the same place. my main problem is that I can't seem to get a 9v reading no matter what way 8 put the diode. I have managed 10.58 and similar but then it's too low on crank. everything I've read says use a 3.9v or a 2v but none of this is working. I've been at this for several months now and it's starting to look like matches and petrol are the only option lol ... .. HELP!!!
my situation is the same as all the others have stated but I can't seem to get anything at all. I have even tried the external 9v battery and nothing. I have two known working ICU so I know it isn't those.

 

Hi Kermit, as it is a UK bike, does it have the HISS system installed?
If that is the case it will not have the zener diode pink wire issue.

 

That is a 100 ohm resistor, not a zener diode!

 

Indeed, another reason I am wondering that it is not the 9v US bikes issue.

 

I know. as I said, this is the one that was installed when I opened the loom. I am now using Honda spec zener diodes rather than resistors.