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Discussion Starter #1
Hey all! I had an account on here way back and can't, for the life of me, find my username even when using the search bar. Anyway, I had a 1994 CBR900rr that died on me a few years ago. I sold it because life dealt me an unfortunate hand at the time. I do remember IanDoohan and Duncan893 trying to help, though- your usernames look familiar! Glad to see you're still around here.

I found a 1995 CBR900rr for sale for $800 and trucked it home in my pickup. It's gonna be my baby, since I had to give that other one up. Its condition:
  • Not running.
  • The battery was fully dead
  • The fuel pump had some interesting wiring that bypassed the relay with a general hardware switch

With a new battery, the bike turns over strong in neutral. The starter relay clicks and sounds normal.

I figured I'd wire the pump up properly again and test it to get fuel into the engine.
  • When plugged into the proper connectors and the starter pushed, there was no priming or running.

So I wired it directly to the battery, and it pumped fuel.
  • The fuel relay must be dead.
  • At some point I'll swap that relay with the turn signal relay since they are said to be identical.

I connected the pump to the carbs properly. I turned it over and engaged the pump directly to the battery after a few seconds.
  • No burn.

I know these can run without pumps. Since my tank doesn't have a vacuum petcock, I connected it directly to the carbs and opened it up with fuel in the tank.
  • No burn.
  • So it is not the pump.

I took out a spark plug and grounded it against the engine.
  • No spark. THIS IS THE MAIN ISSUE. NOTE TO SELF... CHECK FOR SPARK SOONER NEXT TIME!
  • I then grounded it against the battery's negative. Still no spark.

I checked the battery voltage at the CDI and found it to read normal.
I checked the pulse generator resistance at its connector and found it to read normal. I HAVE NOT CHECKED THIS AT THE CDI.

I bypassed the clutch switch by connecting both ends to a 10A fuse.
I bypassed the side stand switch by unplugging it.
I tested and confirmed the neutral switch to work at the CDI, and found it to work.
I found the kill switch to work properly- MAY HAVE TO CHECK AGAIN.

I tried grounding all four spark plugs at all four plug cables.
  • No spark from any plug at any location.
  • It's possible that they were all fouled.

I ordered new CR9EH spark plugs, then tested a new one at all four locations.
  • No spark.

I checked the resistance of the coils.
  • Roughly 2.5 ohms between the small-gauge wire connectors on both coils. I HAVE NOT CHECKED THIS AT THE CDI.
  • Roughly 21 k ohms at the plug ends of ONE coil, and ZERO k ohms at THE OTHER coil's plug ends. These cable are probably bad.
  • Roughly 13 k ohms at each coil with the spark plug cables REMOVED.

The coils themselves seem to be normal. This led me to check the small gauge wires leading to the coils on the coil end (not the CDI end).
  • I get 12 volts when touching all of the wires individually to one end of the multimeter and the other end to the positive of the battery.
  • I get continuity to the ground at all four of the wires.

The manual states that if none of this works, then my CDI is bad, so I ordered a CDI from eBay.

They are both for 1995 CBR900rrs... but mine has a different connector. I've attached pictures. The labeled one is mine, and lacks that little curve in the bottom right corner. The pin holes are different too.

Should I spend the money to test a different CDI? I'm returning this one.

Does anyone have any other ideas? I'll check the pulse generator, coil, and kill switch connections at the CDI but I have a feeling none are grounding right now. This is killing me, haha.
 

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Both can’t be 95’s with 2 different connectors. Got a pic of your connector? A good one, showing all the wires while plugged on your CDI? I might be able to verify what it actually came off of. “Might” lol.

You could also try a cheap set of known good coils from eBay. They are cheap enough nowadays. Got pics of the bike itself? I would like to see as much of it as possible.
 

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Also, do you remember your old username? I might be able to find it, after being blessed with Moderator status ☺
 

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Discussion Starter #5
Alrighty I am back. I am so sorry for the delay. I worked double shifts the past few days, and then it snowed...

@IanDoohan I'll get pictures of the CDI connector and the rest of the harness, as well as some of the defining components. I think my old username was Daggergt? Something like that but my stuff could've been archived.

@MrPickwick I'll count em. I didn't know that you have to jump the wires for it to run. Will that stop the bike from getting spark, but not stop it from turning over?
 

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Alrighty I am back. I am so sorry for the delay. I worked double shifts the past few days, and then it snowed...

@IanDoohan I'll get pictures of the CDI connector and the rest of the harness, as well as some of the defining components. I think my old username was Daggergt? Something like that but my stuff could've been archived.

@MrPickwick I'll count em. I didn't know that you have to jump the wires for it to run. Will that stop the bike from getting spark, but not stop it from turning over?
Its academic really as you have the clutch switch bypassed, in the same way you can pull the clutch in to start up in gear
 

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Discussion Starter #7
109087


Well look at this... in the manual it says if I don't put the stand up (or jump the connector) then it won't turn.

But mine turns without the connector being jumped, and without the clutch being jumped (in addition). Why is that?
 

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Discussion Starter #8
Note that the above chart applies to it being out of neutral. Does the neutral switch override both the kickstand and clutch switches? Or just one...?
 

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Safety thing to have it in gear and sidestand down at the same time as start up to stop you riding away with it down, connects to Clutch Diode and ECU
 

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You could bypass the Side Stand Switch and make sure its not in gear ,do you have a neutral light that goes out to prove that link, as you have bypassed the clutch switch you should be good to go, if you still have no spark then we have to be looking at the Ignition pulse Generator as the next step (y)
 

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Discussion Starter #12
Yep I tested the neutral switch exactly as stated in the manual. It works, and the neutral indicator light turns on and off properly.

The ignition pulse generator shows the correct resistance at its connector, roughly 464 ohms.

I think get the minimum 1.7VAC while cranking if I recall correctly.
 

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Did you put the jumper wire in the connector harness side of the side stand switch , connecting Green to Green/White.
 

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Discussion Starter #14
No, I didn't know I had to jump that. But the neutral switch in neutral plus the clutch switch being jumped/shorted should override that, right?
 

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Could just be a faulty switch, and if its jumped it will eliminate it from the list, disconnect the connector and jump it on harness side and see how that goes (y)
 

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Discussion Starter #19 (Edited)
Alright, it was warm enough today to work on it. I plugged in the pulse generator and jumped the Green pin to the Green-White pin at the kickstand connector. The neutral switch had the green indicator light on and the clutch switch was unplugged and shorted at the connectors.

The battery had 12.17 volts and the spark plug I was using was new. Still no spark.

Any ideas? Pictures are in Post #16... Replace the coils or pulse generator maybe?

Before I replace the pulse generator, I'd like to make sure that it's broken. My manual doesnt explain how to test it fully. Can anyone link me to a resource on how to test each ignition circuit component?
 

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Unplug the 2 prong pin going to the pulse generator, the positive wire should show .4 to .7 volts on multimeter. I had a similar problem with a sc33, tried to get spark for days. Finally started today. :D These bikes will not start with even a slightly discharged battery. The icm shuts off spark. That is why it is impossible to push start with low battery. Put some jumper cables on and hook it up to a running car. Make sure you remove cables from bike as soon as it starts or you may fry your rectifier. Take off the positive wire to the rectifier, if possible, while jumping.
 
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