Hey,

I have over half a century on the planet and have been a motorcyclist since I was a kid, but I am new to the forum. I recently got a 1990 CBR600 that had been sitting at a neighbor's house for 10 years.Apparently it quit running after a low speed fall on the right side. No visible damage aside from a few scrapes on the plastic. The good news is it was kept indoors. The bad news is I can't seem to get it to spark or run the fuel pump despite trying the troubleshooting suggestions and procedures I have been finding from various sources. I have verified all switches are functioning, checked battery voltage, confirmed power to the positive sides of the coils, changed the fuel cut relay with a new one, confirmed the fuel pump runs when the fuel cut relay is bypassed, cleaned all the contacts on the ECU plug and ECU unit, verified power through the yellow/blue wire at the tach, at the fuel cut relay and at the ECU plug. The pulse generator coil reads what looks like good. I am grounding plugs directly to the head and still not getting any spark in either coil. I found a used ECU for a price I am willing to pay so I plan to buy it but I am not convinced the ECU is the problem because I haven't found info on how to test it without the fancy rig shown in the factory service manual. I understand that the fuel pump is supposed to stop in the event of a crash and that the ignition doesn't fire in that case, but there does not seem to be a sensor that tells the bike it is down (at least as far as I can see from the wiring diagram). So if anyone has more tips on this one I would appreciate the help.

I have been restoring life to unloved bikes most of my life and I consider myself an accomplished wrencher but this one is causing me to wonder if I am just going senile.

 

Just a thought.
Does the killswitch on the 600 isolate the starter or not?
If not a faulty switch could give you the symptom you describe -no spark and no fuel pump . The kill switch will isolate the ignition coils and also the the pump relay.

 

The starter runs with the switch in either position. It reads open and closed when it should according to the test meter. I am pretty sure I have checked all the obvious/easy possibilities at this stage. I did pull both coils and found that neither one shows continuity when read from the green terminal to the plug wire although the black to green reads ok and has battery voltage with the ignition switch on. That suggests to me that the secondary windings are bad on both coils. Not sure what the odds are that both would just fail simultaneously but if that is the case then something is else is likely to be wrong and causing the high tension side of the coils to short out.Next I isolated each coil and set each one at a time up on my bench with battery voltage in the primary side and put a plug grounded to the neg. side of the battery. By charging and interupting the primary side of the coil I was not able to get a spark from either one. Conclusion - both dead. Looks like new coils too but I need to figure out why they died before installing new ones.

 

You're right it is unusual for the coils to fail that way. I really can't think of what you could do to damage them intentionally or otherwise. If they don't spark though, then what can you do but replace them.

As for the fuel cut off, these bikes don't have that. What you're referring to is the Bank Angle Sensor. That came along on fuel injected bikes because of the high pressure fuel lines and fire hazards.

Were the carburetors drained during this storage period (not likely I imagine) ? Getting all the little passageways clean will probably be one of your biggest challenges. But as you said, you've been doing this a while, so you know what you've got ahead of you.

Good luck

 

I have already completed the carbs/tank/lines and they were surprisingly clean. The fact that the fuel pump would only run when I jumpered the black and black/blue wires at the fuel cut relay plug was my first indication that things were not right with the electricals. I got the name of the relay (fuel cut) from the OEM schematic and ordered one after reading a lot of posts where people found them to be the problem. No help though (and $65 down). The realy supposedly cuts off the fuel pump when it gets an indication from the ECU that the engine has stopped even if the key is on.

I am starting to suspect the ECU even though I still don't know how the two burnt coils figure in. Only way I have to check it is buy another one. Oh boy.

 

It may be more cost effective in the long run to get a good auto electrician to go over the bike. He'll have the know how and may find the fault a lot quicker than doshing out for parts that may not cure the problem. If he charges by the hour then that might be the cheapest and successful way to go. I had a BMW car once that had running problems that drove me mad and I spent loads of dough trying to sort it. Eventually, I paid an auto guy to take a look and he sussed it out in no time! Turned out to be two cables touching one another, but they were inside the outer cable. Doh! Just an idea and it may work and save you time, money and frustration!