No spark on all four

[Ironride]

Arrrgggg! My 79 XS1100 special is DOA, (dead on its axles)! It was running fine when I parked it, then a couple of days later I went to start it and it was missing badly at all RPMs but it really showed up at 3K or more. I shut it down and now it won’t start at all. I checked the ignition with a tester and found I have no spark on any cylinder. I suspect the transistor box as it is affecting all cylinders but would gladly consider any suggestions. Thanks in advance.

Ironride

[Mike Hart]

While the CDI box can do that, it doesn't happen often at all, and when it does, it doesn't usually sputter first before going dead.

Kill switch, sidestand switch, battery high enough to crank but too low to have any poop left over to fire the ignition, flakey fuse, pickup coils, ballast resistor...corroded connector somewhere...lots of water in the float bowls, pinched/plugged fuel delivery...

Helps if you have the service manual, and start with the easiest stuff first.

What kind of 'tester' did you use (and what method) to check for spark?

[strom]

It's probbably the box.
They do stutter at higher RPMs before dying... at least kawasaki ones do.
If u have a friend with the same bike, try swapping. Otherwise, eliminate all other stuff, since these boxes have high prices... Try getting a used one off sbds parts bike.... u can usually get one half-price this way.
If u're lucky u can get the whole parts bike for that kind of $$$.

LP

[Dragonrider]

Check your pickup wires (see tech tips).

[Ironride]

Spark tester info

Hi Mike,
Let me start out by explaining that I am a professional mechanic, which would explain some of the special tools I have. I also would like to say that even though I’m quite comfortable working on motor cycles, it’s not what I do for a living. That’s why I find the information and experiences of good people like yourself and the others that post here a valuable diagnostic tool and time saver. Now for how I checked the ignition. I used a PET-4000 pulse ignition checker made by Oppama Industry Co. It’s a neat little spark tester that not only shows IF you have spark, but also can be used to test how well your ignition system is working, and will work on both terminal stud and terminal nut type spark plug caps. Before testing the ignition I put a charger on the battery just to make sure it wasn’t just a low battery problem. I replaced the fuses and cleaned some of the connectors and applied dielectric grease before reconnecting them. That is as far as I’ve gotten but I plan to get back at it this weekend.

Ironride

[Mike Hart]

Awesome!! Do you live in Washington so I can come use your tools?

Ok, no spark. Pickup coils fail on many bikes, cdi's on few. For more info on that problem and the fix, with pix too, see Ken Talbot's page on that.

Since you are a mechanic I trust you have eliminated all fuel delivery probs, and you assure me the battery is ok. So - it's gotta be one of the other two. Or aliens?

But... kill switch innards are easy to check, it happens. Does SF have sidestand switch and clutch switch too? If so, they go to a relay that won't let the bike fire if any 'safety' switch is ng, so could be that relay too. Do you have service manual or wiring diagram?

Looking forward to hear soon that you fixed it , and what it was.

[nashville_bill]

If it turns out that you need the ignition box, there is one on ebay now. You can bid on it or "Buy It Now" for $100.

[TopCatGr58]

Hey there Ironride,
I remember reading a post/story recently from the Triples list, about a guy that checked out the CDI boxes for failures(he was into trying to re-engineer them, and many were just broken solder joints, and once resoldered, they worked. You might want to take your CDI unit off, and open it up to inspect the connections, might find a corroded/broken connection that you could easily solder/repair and it MIGHT work?

Worth a few minutes to save a hundred bucks!?!? BTW, welcome, nice to have another master mech(present company excluded!) for cage references!!

[Mike Hart]

I've recounted that same story here several times. Bad solder joint on power transistor, it happened to me. It's still not a common failure mode on 1100's. You never know, that may be what you have too.

[Ironride]

IT LIVES!!!!

Ok, I finely got a chance to check the bike over properly and found the trouble was in the panic kill switch. I cleaned it up with electronic parts cleaner and it seems to be ok for now. I guess I’m going to have to keep my eyes open on ebay for a replacement as the Yamaha dealer in Madison (Wisconsin…where I live) told me it was no longer available. Speaking of ebay, just for grins I took a look at the CDI unit that nashvill_bill mentioned thinking I would like to have one for a spare. I found another one there going cheep and picked it up for under $32. I would like to thank all of you that had written with your ideas and suggestions. I learned a few things from you, such as poor solder joints in the CDI unit. That’s a good bit of info that may be helpful someday.

Ironride