KZ has no spark...

valvesprung

valvesprung

Over 1,000 Posts
So after a $211 bill at the bike shop my bike was running like never before. It fired first kick from dead cold, and held a perfect idle. I couldn't have been happier...then I went to go start it yesterday and got a huge load of disappointment....

I kicked her off and she fired right up...then died. A few more kicks and no luck so I gave full throttle (clear flood) and she fired but was running on one cylinder or both very poorly. It would barely pass 2k RPM at full trottle. I pulled the plugs and found soaked, cleaned and tried again. Now I have no spark what soever. All of the wiring is intact and unobstructed, but still no spark.

I'm completely stuck. I've considered a new coil, but my bike budget has been cut-off until my savings recovers from some unexpected bills and I have my MSF class in one week...

If I can't figure this out for next to no cash It may be next f-ing summer before I get to ride her. I've working on this bike since last august to have it ready...I'm depressed out of my skull...

Please help me.

BTW it's a '77 Kawa KZ400
 
Valvesprung

There may be some good news. When things go from running great to no spark that usually indicates (to me) that it's something very simple. Do you have no spark or no power period? CLEAN TIGHT battery connections are ALWAYS an imperitive place to start. Use fine sandpaper or a wire brush to clean both terminals and the connector leads.

After that I think you need a wiring diagram and a multi meter. The wiring layout will be in the manual. If you don't have a manual you should. The multi meter could be a cheapy from Crap Tire. You could probably get by with with a bulb connected to two wires to check for power - but a multi meter will speed things up by allowing you check for continuity

With a little patience you can follow the wireing diagram back from the plug wires, coils, right to the battery. Then work back through making sure you have power at each stage. It's tedious but fairly straight forward.

The manual will also tell you how to check the coils and HT wires, check point gap and timeing all of which could cause no spark after checking that you have power to them.
 
grab some new plugs and try, when you say plugs where soaked to me sounds like you fouled them bad, meaning your carbs probaly way to rich try new plugs, if she fires up do a plug chop, ride for 5-10 minutes pull plugs and check tip colour, should be chocolate brown, if there plack your to rich and will foul plug, if whiteish blue your lean and going melt plug.
 
I'm quite postitve the fouling has nothing to do with the mixture (the pros just re-jetted it) and everything to do with a weak and now non-existant spark.

Fortunately I am an automotive technician snd just so happen to have a $200 bar graph voltmeter and be fairly strong in electrical. I'll admit I get a bit thrown off when I look at the bike, even though I know the basics are the same. I'll start tracking the wiring, but I suspect a failed kill switch or coil.

Thanks for the input, any more is still appreciated.
 
VS

If you really get into a pickle I have the wiring diagram for your bike. I could pcopy and mail it.
 
Thanks, I forgot to mention I do have a shop maual. It's a bit more general that I'd like (1974-1995...), but it works. The only rear discrepancy I've seen is wire colors vary slightly.
 
New symptoms...

Now I have no fuel on the plugs at all, the plugs seem to be firing fine. The petcock was leaking pretty heavily, so I tore that down and cleaned and resealed it. It is deffinately flowing normally now, but very little/nothing seems to be getting into the cylinders...

This bike hates me...
 
You are not alone....I'm this close to backing my truck over my bike and buying something new....
 
That's what I spent over $200 for...they cleaned up the sediment and laquering from the bowls etc...

You can all understand my current frustration.
 
Thanks for all of the help guys.

She runs, and runs like a champ.

I'm not sure if it was the worn wire insulation I repaired, the cleaning of the carb, the new spark plugs, or the filling of the battery (it was out of water, but mind you it was being tested on a charger), but it runs.

I took it out for it's maiden voyage yesterday now that I have my endorsment and had a blast.

Thanks again for all of the words of wisdom.
 
I've recently been having what I think are spark issues with my xs. It began fouling the left plug after a 30 mile or so ride. Carbs are dead on. I swapped the coils side to side to see if it follows the coil but haven't had time to ride it until the plug fouls yet, proving my theory of a dying coil. A couple trips around the block though and the left side remains good while the right is already starting to look a little wet and blacker. Anyway, runs good for 30 miles then kills a plug. Am I correct in assuming a dying coil? Any insight is appreciated....
 
Did you swap the coils only or did the wires either to or from the coil follow the swap... wires are cheaper and easy to replace... make sure it is indeed the coil.

Other than that it should be the coil if the issue is following the coil and its the only thing swapped.
 
Coils along with the wires as a whole.....I replaced the wires and caps when I got the bike, but the coils are original. I am hoping to take it out tonight for a few miles to get the plug to foul, it sucks that it doesn't happen until a half hour into the ride....obviously I don't want to be far from home and i feel silly lapping the neighborhood!!! I'll let you know what comes of it, Thanks for the help
 
Nate said:
Coils along with the wires as a whole.....I replaced the wires and caps when I got the bike, but the coils are original. I am hoping to take it out tonight for a few miles to get the plug to foul, it sucks that it doesn't happen until a half hour into the ride....obviously I don't want to be far from home and i feel silly lapping the neighborhood!!! I'll let you know what comes of it, Thanks for the help
Click to expand...

What about the wires to the coils and those connections?
 
Well, consistent with the inconsistent nature of this bike, I swapped the coils and wires and now the problem seems to have gone away.....that's what drives me nuts with these old bikes is they run fine, then break down, then run fine again fo seemingly no reason!!!
 
Nate said:
Well, consistent with the inconsistent nature of this bike, I swapped the coils and wires and now the problem seems to have gone away.....that's what drives me nuts with these old bikes is they run fine, then break down, then run fine again fo seemingly no reason!!!
Click to expand...

Well now it sounds like a corroded connection or even a break in the wire under the insulation... just moving a wire around can make the problem appear or disappear. Even the new sparkplug wires are suspects... but I would bet it's upstream of the coils.... whether ground connections or leads.

I'd go through the ignition harness with a multi-meter checking for continuity while wiggling things around... and clean all the connection points while your at it.
 
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