Topic: CL350 Intermittened Sparking

[JeyLux]

So, i've been having a fun struggle with the CL350.

I tracked it down to intermittent spark on the left cylinder.  (I did this using a timing light inductive on the wire...)

I then swapped plugs into it.  Same issue.

Change spark plug boots, same issue.

change the spark plug leads from one side to the other.  Still follows the bad coil.

Swapped around the wiring on the point system now, and, the issue still lies with the same coil.


So, after fuddging around with it a bit, when you run the bike (yes, it will run on 1 cylinder...) you rap that RPM's up to 3800 (think, advancer-plate)  it starts to spark better, not 100, but close.

Now, if i retard my system a lot, it will also a spark a little better.


Timing has been set 90 or 100 times now.  valves have been clearanced, new points (denso) and new condencer, new spark plugs, new boots.

same issues as without the change.

I know what you're thinking though... it's not timing related.  He's my hypothesis... tell me if it makes sense...

less "dwell" (contacts closed to create charge in coil) less voltage in coil... thus i might have some sort of insulator issue internally, and it shorts out with too much time in the coil...

that would explain to me why the retarding works, and when you advance it works...


but, i don't think coils should fail with intermittent sparking... it's tough.  I see a couple other threads on here talking about a similar issue, but no real resolution that it was in fact a bad coil.

I hate to spend 120 bucks on some Dyna-S's (is that what I should be buying??) if it's just a simple wiring issue some wheres...


Anyone have 1 extra coil from a CB350/CL350 that they know works and is willing to sell??

If it fixes the problem, i'll give you two coils for it.  and order the Dyna-S stuff.  Just hate to waste the money for no reason...


Thanks!


Also, I bought a CB500f ... since the otherboard is down, i didn't get to share in the glory.

[rchrdms]

Hi,

I had a pair of bad coils and it took me a year to find some good ones. Plenty of people on Ebay have coils that 'spark' but they have to have the right resistance.

The power goes down as resistance goes up, so any deviation above the spec makes for poor running.

Have you bench-tested these coils with an ohm meter? That should tell you if they need replacing.

The specs for dual-point models are:

3 to 5 ohms resistance between both primary leads of each coil(the black/white and colored wires(blue or yellow);

10,000 ohms resitance between either primary lead of each coil and the secondary lead(spark plug wire);

Check for zero continuity between coil frame and high voltage wire.

This is for a CL 350 twin bike with dual points.

Good luck.

Richard

[JeyLux]

Thanks, I haven't been with my motorcycle as I've  been on vacation. I hope to figure it out when I get back. Summer is drawing to a close, and i need to put some miles on that beast...

I will give this a try when i get back.  I wanted to buy new ones, as I don't like used parts that much.  Just trying to figure it out before i waste 120 dollars!


Thanks,

Jason

[kirkn]

Try an el-cheapo old fashioned 12-volt automotive coil, just to test the circuit.  They'll work like a champ!!

I once was troubleshooting a '74 KZ400 and I used this trick just to test the rest of the circuit, and I happened to hit the starter button WITHOUT a spark plug lead hooked up, and a spark jumped from the coil lead tower across a 3/4" gap to the frame!!  Surprised the $%!* out of me...

[Bliss]

I have been using universal coils from ebay or JCwhitney, about 20.00 each I found them on ebay for 22.00 a pair
same type of coil on britsh twins. they work great

[JeyLux]

I ended up throwing some dyna coils on, and it works great now.  quick starting too!

[Green550F]

What most people don't understand is that coils can be "bad" when running but test ok. This is due to the fact the coil is seldom tested at the levels where the insulation can fail.

[JeyLux]

What most people don't understand is that coils can be "bad" when running but test ok. This is due to the fact the coil is seldom tested at the levels where the insulation can fail.

indeed this is the issue i believe i had. 

I didn't change anything else, other than the coils.  The connectors were great etc....


as it goes.