So i have a 1999 CBR 600F4 that i got in a trade and the previous owner couldn't get it running and said there was no spark and they had replaced the fuel pump and stater. I changed the oil, replaced the spark plugs, and put in a new battery. I also cleaned out the carbs and the fuel tank. Everything seems to be in working order and it turns over nicely, but i read a thread on this forum that said that the zener diode in the base of the ignition switch will keep the pump from priming and the spark from sparking. I'm hoping somebody can help me locate were the zener diode is on these bikes so i can get that replaced and hopefully get this bad boy running again. I took the ignition switch apart and could not find a diode, just regular simple contacts. I know these have been a frequent problem on these bikes but i'm not sure were to look to find it. There is a pink wire that has been cut and twisted back together making it shorter then the rest of the wires in the loom and i'm just wondering if that is were the diode is normally found and that somebody just cut it out. If somebody could help me out with this that would be awesome, this is my first time dealing with a street bike and other than the basics i don't quite know much about bikes. Below are pictures of the wire i was wondering about.

 

Correct , the pink wire carries the diode, could have been an ignition switch change, the Chinese ones don't carry the diode

 

Helped a guy over at the Fireblades forum...might take a look:

Where to get diodes - Honda Motorcycles - FireBlades.org

 

Alright guys so i installed the new zener diode and yet i still have no spark and the fuel pump only runs for half a second when you turn the key on with the engine kill switch on run. I am at a loss at the moment, i cant seem to find any reason why this thing should not run, nothings been spliced into and other then some broken plastics it doesn't show any signs of being wrecked very hard. Can anybody point me in the right direction to where to look to figure this thing out?

 

That diode needs to be soldered into place ,the wires wrapped round wont do it

 

Should be good enough for a test. Yes, later it needs to be done correctly.

Measure the voltage on each side of the zener (negative meter lead to a good ground, and then positive lead to each side of the diode in turn).

You fail to say what diode you used. And know that if the diode is installed backwards, it will not do what it needs to do to allow the ECU to work.

 

Hi matey, think we are barking up the wrong tree, just re-read your post, 1999 carbed bike, ordinary pump ,ICM not ECM, to check get one of those household small 9v batteries undo the pink wire and resistor put a connection from the + terminal of the battery onto the pink wire harness side and a connection from - side to a good earth giving you 9v to the ICM, see if it will fire

 

Echowars i used a 3.9V 0.5W Diode, Part number NTE5007A but it does no good at the moment for i have 0 volts through that wire for whatever reason. CaBaRet thank you, i tried the 9 volt battery idea and after hooking it up i turned it over and i had spark from the plug i had pulled out the night before, i buttoned that back up and hooked the fuel tank and cranked her over until i figured out that the hoses on the pump were backwards, so i swapped them and finally got fuel up to the carburetors but still no sign of it wanting to start. the battery was running low so i let it charge up a bit and pulled two of the spark plugs to check spark again and lone behold i dont have spark again. could it be that the battery is just not charged enough yet? i will test this theory tomorrow after i let it sit on the battery tender all day.

 

Think your making progress, yes good charge on the battery and who knows, think echowars could be right about the diode being in back to front though, the anode and cathode have to be the right way round

 

Well ive got the battery charging, and I'm fairly certain ive got the diode in the right way, but it won't do ant good because when I tested the voltage on that wire when I turn the key on and also when o crank the bike over I don't get any voltage whatsoever, and I'm pretty sure that's not good either, but if I can get it to start with that 9v battery then I can just wire in my own switched 12 volts to the diode and then wire the other end of the diode to the pink wire goibg to the ICM.