Pick up coils, TCI and ignition coil trouble

I have an Xj650 maxim 1981. I am having some trouble with my ignition system. I bought it a couple of months ago and I thought that it was just a carb job, but ended up being allot more. Having done the valves, cleaned the carbs, fixed the turn signal electronics and much much more, it is running a little beter. But the 3rd piston is not firing properly. I have swapped the leads and the same thing happens on the other side. I check for spark and there is spark on all the leads. I have tested the coils, primary and secondary and they seem fine enough. The pick up coils looks like a new one and I have searched high and low for bad wiring but to no avail. Is my TCI screwed? I did notice that my diode in my headlight was smoking one day but everything seems to work. Also my starter only starts in neutral, but yesterday it started with the clutch pulled in, but not today. It runs, but not very well. HELP!!!

 

Pope
I'm left wondering if the plug wire to the hole that isnt firing well is broken inside or corroded under the insulation!?
If all the other 3 hole run good but the one that would be my best guess.
As for your other electrical gremlins....
Good luck

 

Because this is a wasted spark system, there are very few things that can cause a spark issue on only one cylinder. The TCI is not one of them. So, if you really only have spark problems on #3, the TCI is good. The only things that can cause a spark problem on one cylinder in your bike are the spark plug or the ignition coil and its wires and caps; but even that's really rare because both plugs on a coil share the same high tension circuit... you'd basically have to have the current shorting from somewhere to chassis rather than going across the plug's gap.

When you say you swapped wires and had the same problem on the other side, you should mean that you swapped 2 and 3. Is that correct?

How do you know that #3 is not firing properly?

 

I had this problem myself.
My #1 plugwire had gotten corrosion under the boot and into the wire.
My bike had trouble on just one hole which meant it was related to something that had to be unique to just that hole.... I didn't think to swap the wires soit took me a bit longer to figure it out.
The big thing is that there is a way to replace plugwires.
There are threads on this site on How To....

 

Funnily enough, I had much the same problem as you described yesterday, The bike was running fine, then started to misfire and then only running on three plugs.

Now I automatically assumed that because I was running lowish on fuel, it was the warning of imminent running out of fuel. I managed to get to a garage and put fuel in, but the problem still persisted.

Of course, my next thought was "Oh no, crap in the carbs because of running so low of fuel" (No I have to admit, I don't have an inline filter fitted... Well I didn't have until today).... I managed to get the bike home, and was about to began to strip the bike down, and for some reason, desided to swap the leads around and try it again, this time it was the other cylinder that was missing, and it was still running on three cylinders, which counted out in my opinion, dirt in the first carb.

Anyway, I'd already got the tank lifted off, and everytime I hit the starter, I heard a "Cracking sound" but couldn't seem to find where it was coming from (it was like a lead or cap was arcing out), it then happened again a split second after the starter was released.

So I got my lady friend to kepp hitting the starter, whilst I got my head into the engine, and when I looked up at where the coils are mounted, I was greeted by a huge blue spark jumping from the coil (at the point where the leads actually come out of it!), and it was jumping a good 10mm if not more, from the coil, to either the coil mount, or the frame! Which is exactly what SQLGuy has described.

These were Brand new coils bought and fitted in March this year. I contacted the company I bought them from and told them what was going off, and they said that I was the fith person yesterday to call them with exactly the same problem - Looked like a faulty batch.

Anyway, 7.55am this morning, there was a knock at the door, and a man standing there with replacement coils for me, and to take the faulty coil and the good one back. Fantastic service.

So my advice, for what its worth, is check that you don't have the same problem.

I certainly believe that it's something to do with that one lead on yours, as you said that when you swapped the lead over, the problem transfered to the pot it was now connected to, I can't see it being anything else.

 

Thanks for the quick reply, I'm liking this forum already.

Thank god it's not the TCI as new they are $550 and used they are $150, so thanks for pointing that out. Yesturday I thought that it must be a grounding issue so I traced the ground from the TCI all the way to the coils and could not find where it was grounded. So I grounded it to the batterie. Now it runs better but I still have the same issue.
Okay here is where it gets weird.
Before when I swapped the leads it did transfer over to the other side. Now when I transfer the leads it does not. So I thought, Now it's got to be the plugs! so I replaced all the plugs and I still have the same problem. Then I checked the timing, Timing is on the mark and when I accelerate it advances. So Now I am thinking its the carbs, and possibly the throttle cable.
Symptoms
rides good, then when I stop the idle starts to slow down to a stall. Have to keep pulling the throttle to keep it going. When I adjust the idle screw it comes back to life. Then when I ride it starts revving like crazy, and when I stop, the rpms won't stop until I turn the idle screw back down. Then back to the beginning. Funny, I was thinking of checking for a spark on the wiring this morning and when I checked this forum Pete comes up with his story about his coils. Will do that today. After that I am getting a priest....

Oh and Hvnbnd! the link, can you send that again, it did not post for some reason.

Cheers,
Pope

 

Run the bike in the dark and look for arcing from the 2/3 coil and/or it's wires to chassis.

Check the resistances of the caps on the 2/3 coil - should be 5K Ohms.

It's not a grounding issue. The TCI has a black wire running to it on one of its connectors (I think it's the 6-pin one) for ground.

My bet would be that you'll need a new 2/3 coil, or at least "coil surgery" to replace the wires, and new caps (NGK YB05F for 2/3).

 

Just want to resolve this thread for others out there. It ended up being both coils that were bad and needed to be replaced. Thanks for all the advice.



81 XJ650

 

Wow..2 year follow up!. Good to hear solutions though!

 

I'm hoping this is the answer to all my problems because I'm haveing a similar issue. I cannot get the bike started and it's only firing on one cylinder sometimes, with brand new coils. I've done just about all I can think of electrically but can' t get any spark