Now a coil is playing up!?

[mr blackstock]

G'day,

After putting on a new NOS cbr600 shock, getting some roller bearings for the conversion, (thanks again to Arnie for the write ups) and discovering overly worn pivots, struggling with greasy issues, then getting the bugger installed.  I also installed a rear master cylinder kit, to be nice to the girl!  Even fitted a new oil temp guage, so I could watch her temp on those long hot days we are getting....I go to start her up to balance the carbs, and she's missing on no.2!  It turns out to be the coil lead is not giving any spark...so out the coil comes for the resistance tests, she has too much resistance, the manual states 2.4-3.0 Ohms acceptable, she came in at 3.4 ohms.  So now I get to buy her some new after market coils at $100 each.

I love the bike I do, but damn it's like she has a soul!  Every time I get under her skirts she throws out old parts...  like a bike version of Christine.  my fault perhaps, you see I name every vehicle, her name is lilith.  Traditionally the seductress of men, luring them from safe paths that they might flail themselves upon the rocks of oblivion in pursuit of Lilith's beauty.....just like an FJ I figured....

[TexasDave]

Just like all women the pretty they are the more maintenance they require.    Dave

[ribbert]

....her name is lilith.  Traditionally the seductress of men, luring them from safe paths that they might flail themselves upon the rocks of oblivion in pursuit of Lilith's beauty.....

....and here's me thinking she must be the Goddess of Empty Wallets.

[Joe Sull]

Maybe you should have named her "Bertha" or "betsy" the holsom and never failing girl 

[movenon]

I don't know that I would be so quick as to say its a coil yet.  Because you say a lead is not giving any spark I would think that you would have 2 plugs with out any spark if the coil was bad ?

You might have done all this but if it was here this is what I would do.

Insure the ignition wires are on correct. (hey stuff happens)
What is the B+ voltage at the coils (probably the red/white wire) ?
Unplug the TCI/CDI unit, clean and inspect the terminals. Reseat. (while you are there do the same for the pick up connector, the smaller connector)
Install a new plug or plugs.
Check the secondary plug leads. 12K + - 20% resistance between the 2 spark leads. (you can replace any or all four plug wires) Wires are non resistive.
Check the plug cap very carefully. I think the plug caps are resistive.
See if someone has a coil you can swap out to see if that fixes the problem.

Hope that gives you some idea's. I hate to see you spend money on a coil or coils until everything else is eliminated. That's all I can think of at the moment.
George

[mr blackstock]

G'day,

I tested the primary and secondary windings, as per the manuals instructions, the Ohms on the primary were at 3.2, whereas the manual stated 2.4 to 3.0 ohms were within limits, so i figured "bugger it, 28 years is a good service period."

I did the coil re-wire around a year ago, worked great.  I checked all the wiring, but I gave in early to the idea of buying a new part.  I will admit, everytime i get her a new part, she runs better!  She is telling me something I tink...

Cheers, Gareth

[rktmanfj]

her name is lilith. 

Now, that's a name I've not seen on an FJ list in a long, long time...     

[FJ_Hooligan]

What George was trying to explain is that if the coil is bad you would be "missing" cylinders 2 AND 3.  Maybe it's just a bad plug wire or cap.  Before you trash the expensive stuff, check out the cheap stuff first, regardless of what the ohm meter is telling you.

[movenon]

What George was trying to explain is that if the coil is bad you would be "missing" cylinders 2 AND 3.  Maybe it's just a bad plug wire or cap.  Before you trash the expensive stuff, check out the cheap stuff first, regardless of what the ohm meter is telling you.

+1 Thanks.  The reading on the low voltage side (primary) of the coil with an ohm meter just tells me that it is making continuity and not in an open state.  Its just a coil of wire.  Looks good to me ?  Let us know how it turns out its an education for all of us, or at least for me 
George

[red]

G'day,
I tested the primary and secondary windings, as per the manuals instructions, the Ohms on the primary were at 3.2, whereas the manual stated 2.4 to 3.0 ohms were within limits, so i figured "bugger it, 28 years is a good service period."
I did the coil re-wire around a year ago, worked great.  I checked all the wiring, but I gave in early to the idea of buying a new part.  I will admit, everytime i get her a new part, she runs better!  She is telling me something I tink...
Cheers, Gareth

G'day,

The Ohms reading on a coil should not go up, as they fail.  They should go down, because the coils would be shorting together.  A four-wire Ohmmeter can measure that small resistance accurately, but a two-lead meter may not be giving the correct reading.  The real test of a coil is done with an inductance meter, and it measures in HENRIES or MILLI-HENRIES.  The manuals probably will not give those values, so you would have to test your good coil, and compare the values of the bad coil.  Since one coil feeds two plugs, as stated in another post, you would have two cylinders missing, if you had a bad coil. 

A bad plug, bad plug wire, or bad wire-end cap would be much more likely than having a coil to go bad, and those things would be a lot cheaper to replace, compared to a coil.  Swap the spark plug wire on the bad cylinder with the spark plug wire on another cylinder, and see if the problem goes to where the spark plug wire went.  If not, swap the spark plug from the missing cylinder with the spark plug in a different cylinder, and see if the problem goes where the plug went.  Alternately, you could just replace all the spark plugs and/or spark plug wires, if any one has gone bad, and that may be the best call now, anyway.

Happy hunting,
Red

[movenon]

her name is lilith. 

Now, that's a name I've not seen on an FJ list in a long, long time...     

Lilith was not to be messed with......
George

[mr blackstock]

Thanks for all the good feedback.

Today I made the call and ordered two more coils.  The spark plug caps are new NGK 5 Ohm resistance.  I hear what you are saying with perhaps replacing the plug leads, but considering the current ones are 28 years old, a new set should give the bike a "new" feeling.  When i replaced the starter solenoid, the bike idle great after that.

I will let ya'll know how Lilith takes to the new bits...

Cheers, Gareth

[rktmanfj]

her name is lilith. 

Now, that's a name I've not seen on an FJ list in a long, long time...     

Lilith was not to be messed with......
George

I believe she's now on the FZ1OA, IIRC.   

[ddlewis]

her name is lilith. 

Now, that's a name I've not seen on an FJ list in a long, long time...     

Lilith was not to be messed with......
George

I believe she's now on the FZ1OA, IIRC.   

Lilith.. that would never have clicked on my own.   wow, you guys have good memories.  I'd guess 10 years or so since she was around.

[mr blackstock]

Alright,

Not sure of the effect lilith is having on you guys... before my time I reckon. 

Anyway, the new coils arrived, I put them in, bike ran great, smooth as a kitten purring, except now she is a big bloody tiger!  After about an hour of running the bike started sounding funny, like it's on two or three cylinders!  So I do some tests, and there is now no spark coming out of the coil for No.2 and No.3!

Before I get the "I told you so's"    The bike needed new coils anyway. 

My current problem seems to be the ignition box.  I tested the resistance of the pickup coils, they are within limits, the wires from the coils down to the ignition were not broken, the earth at the coils was good.  The coil serving cylinders No.1 and No.4 are still good, really good spark now, hell the bike runs quite nicely on two pots....

I retro fitted the wires back to the original loom connections, just in case it was the relay I am using for the coil conversion, still no luck....

Am I missing something?  Or do I need another ignition box?

Cheers, Gareth