Back with some more q's please.

[Thunderdome74]

Hi Everyone


So i have had the bike on the road a few km, and she was sounding worse than before (synch)
So the carbs came out again and i am positive they are now clean! (followed mike nixons book)

Pilot jets were pulled and are totally clear
Bench synched
when running i can see fuel going through the filter

Symptoms:
Doesnt go above 7000 under load (no surging, nothing, just gets there and stays)
She starts pretty easily but seems to drop/run on 5 , occasionally running on 6 (sounds fantastic and the clutch and assorted noises dissapear)
The revs fluctualte at around 1k to 1.5 with the bike dying from time to time
[youtube]<iframe width="560" height="315" src="https://www.youtube.com/embed/LbfFMItSK4w" frameborder="0" allowfullscreen></iframe>[/youtube]

https://youtu.be/LbfFMItSK4w

Sorry i tried to embed the video

If anybody has any ideas, or ways to check things further i am all ears as electrickery is not a strong point...
She has new plug wires.
New plugs.
I cleaned coil terminals although 2 coils are cracked.
Somebody mentioned the ignitors might be at fault????

Thanks again.
Thor

[steve murdoch icoa #5322]

You may have answered your own question.
Running out of steam in the higher rpm could be attributed to the cracked coils.

When it only runs on 5, can you isolate which cylinder in not running?

[Thunderdome74]

Hi Steve , Thanks
I picked up a timing light and tommorrow i am going to see if any of the leads give a intermittant signal.
So if it is ONLY ONE of the 6 leads ..(new leads) does this eliminate the ignitors and point to a coil?

I have a bunch of coils from the old sohc 750's
Could these be used in a pinch if anyone knows?
I also have a set somewhere from the GL1000?

I am just trying to nail the problem and setps down before springing for new stuff from ebay

The pipes are all getting hot but i am pretty sure its a intermittant spark on one or even 2 cylinders (pointing to a duff coil?)

Tx
Thor

[Mello]

HI Thor, it fun hunting these things down. On the CBX there is so much that can cause little issues so you need to work through them thoroughly one by one. I've learnt the hard way!

From the video, it seems the sync is still out a little and to me it would seem there is a low speed fuel problem. The carbs can be very frustrating if not cleaned correctly. If you have done this, good. Did you check float levels? Could also be an issue and might be the problem at high engine speed. Not getting enough fuel. I had a great idea with my 79 to put some injector cleaner in the tank once. All I achieved was loosening all the crap that had accumulated over the years. This found its way past the fuel filter and into my nice clean carbs. Then it bunged up the petcock and I couldn't understand why the bike ran out of steam when pushed over 120km/h! Not getting enough fuel.

On the coils. I replaced these on my 79 with dynatek units. Mine had cracks too. Found my issues were actually carb related. Failure to clean properly. Even so, I was happy I had as the coils were old, eliminating a possible problem area. My next CBX did have coil problems. The bike would start and run ok, only for her to start missing badly a little while into the ride, then the battery would start to get drained. Found the coils tested good when cold but the resistance quickly went high after running. Swapped them with some spare units and all good again. If you can identify which cylinders are not running, swap coils to see if the problem moves with the coils. Not sure what other units will work on the CBX, however.

Do your igniters look ok? No black goo oozing out?

Good luck,
Mike

[Thunderdome74]

Hiu Mike , thanks for the reply.

Just saw ou are fom JHB

Ja the gremlins are fun fun fun (when its raining)
I had the tank coated inside specifically to avoid all the gunk going in the carbs.

I am pretty confident regarding the carbs As the bike starts pretty easily.Also 4 was not as hot as the others, but pulling the plug confirmed it was wet.

Float levels wers checked and then rechecked with a clear tube (height) out the overflows

My steps yesterday were to clean all the contacts and i noticed with a timing light the light was not consistant with 3 and 4.
Would miss every 10- 15 flashes and the engine would have an almost imperceptible miss.
Coil error?
Igniter error?
I cleaned everything and the bike is sounding much better, much.
However i was reading late last night and came accross the voltage drop to the coils so today i am going to go measure all the coils voltage and see about doing the 12v from batt via relay mod straight to the coils.

Also i need to double check the battery has a full charge so i can eliminate that.

This might sound weird but it "feels" like an electrical problem , as when the revs suddenly rise there is nothing gradual, rather its as if a switch has been thrown? The cylinder seems to kick in suddenly.ON/Off
But i can be wrong as i am just guessing.

The cylinders "feel" like they are all firing with one or 2 missing and not having FULL detonation due to weak spark?
Can this actually happen?

https://youtu.be/h3sRVb8nytk

If you look at 11 seconds you can see the immediate jump n revs.

I have only done the timing acordin to the marks but I have no ide what the PO might have done with the adjustment of the individule pickups.

[steve murdoch icoa #5322]

Thor, your second video is coming up as "private".

Don't know if your GL or SOHC coils will work but this excellent thread from a couple years ago show some coil testing methods.
viewtopic.php?t=3762

I had a coil that was faulty but it didn't break down until the bike had been running for approximately 5 minutes. I guess it took that long to build up a certain amount of heat to cause the connections to "open".

[Thunderdome74]

Hi Steve

(vid should work now)

Thanks for that i'm going to read through it as it might be pointing to something...

Today:new plugs bought. Took out plug number 4 (looked like it had been firing)and replaced it.
Before doing that i checked for spark with a new plug resting on the tappet
ALOT OF GOOD SPARK
Checked voltage on the coils while running ...12v odd going to 13 when i revved... good?
Recleaned with contact cleaner all junction boxes including those coming from the igniters

Started bike and she sounded Very good. I messed around with some other things over the course of today and started her up this evening

WOW she sounded really good.so good in fact the clutch rumble was nearly gone but i could hear the alternator making some noises so i might put another shim in there.


This idea of the alternator slippage bugs me a bit, metal on metal ... fileings into the oil? I know its been around forever but it seems wrong somehow. Can i put some magnets somewhere or....

Cylinders were all reading similar temps from startup until about 100 c (i stopped around then)
However the RHS 3 cylinders (4-6)seem to read about 10 deg lower that the LHS (1-3) but its a cheap thermometer so....

The problem seems to be gone after a good clean all round (can anybody tell me what igniter the brown 2 cable connector goes to )as i hadn't looked at it yesterday so that mighta been part of the problem?

HOWEVER, the problem might ony rear its head when warm and stupidly i didn't let it get to a proper temp.

Thanks everyone....mote tommorrow

Thor