charging issues

My 79 kz650 sr doesn't seem to be charging. It will start and run fine when jumped from my truck. If i jump straight to the leads with no battery, when i diconnect jumper it dies instantly. If i jump to a known BAD battery when i diconnect jumper it will run a minute then die. This has to be either a bad alt. or a bad reg/rec. Right? P.S. it has a sparkx battery eliminater in place of reg/rec. though i,ve never run without a battery.

Most "battery eliminators" are just a big capacitor. They are meant to replace the battery, but require the use of the original regulator and rectifier. Without the reg/rec in place, the battery eliminator can fry, along with the rest of the electrical system.

If the Sparkx is a replacement for the regulator, rectifier, and battery, then it may be ok.

What ignition do you have, the original points? Or a Dyna S?

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The sparkx unit has built in reg/rec, I believe. It came on the bike when I got it about 3 or 4 years ago. The ign. is Dyna S.

torquey wrote: My 79 kz650 sr doesn't seem to be charging. It will start and run fine when jumped from my truck. If i jump straight to the leads with no battery, when i diconnect jumper it dies instantly. If i jump to a known BAD battery when i diconnect jumper it will run a minute then die. This has to be either a bad alt. or a bad reg/rec. Right? P.S. it has a sparkx battery eliminater in place of reg/rec. though i,ve never run without a battery.

Seems like normal results.

Bike needs a healthy charged battery in order to diagnose its charging system.

Never jump from the battery on a vehicle that has its engine running, as this may damage the bike's electrics.

Am unfamiliar with sparkx.

Good Fortune!

There may be some confusion in the wording in my first post. I installed a new fully charged battery in my bike. After one ride battery had about 6 volts. Then after 12 hours on trikle charger it wouldn't charge to more than about 9 volts. When i jump from bike battery leads (no battery in bike) to truck battery (truck not running) bike starts and runs. Disconnect jumper bike instantly dies. With bad battery in bike, jump to truck battery (truck not running) bike starts and runs. Disconnect jumper, bike runs for about a minute then dies. Sparkx makes a reg/rec battery eliminater combo unit, sold for old brit bikes.

Sounds like your new battery is toast since it will not charge to more than 9 volts. The Sparkx unit was made specifically for Triumphs and BSAs. I seriously doubt that the generator output from those Lucas (as in Junk) equipped bikes is the same as the output from a KZ650 generator. The difference may have fried the Sparkx. In any case, if it was mine I would toss the wrecked battery, toss the Sparkx, and buy a regulator/rectifier designed for the bike along with a new battery. After these items have been installed, if there is still a problem you will then be able to troubleshoot the electrical system with some degree of confidence. Ed

If you do a search on this site you will find many threads about 1978 and 1979 KZ650's that cannot maintain a charge while using a Dyna S ignition. It's pretty common.

The Dyna S ignition takes a lot more power than the original points ignition required.

Apparently some 78 and 79 KZ650's had charging systems that did not have quite enough extra power to keep up with the extra demands of the Dyna S.

The solution that has worked often was to install a 3-phase stator and reg/rec from a later 650 and/or 750-4. The original stator and reg/rec on 78 and 79 KZ650's is 1-phase.

The other option is to return to points, or better yet, use a Kawasaki electronic ignition system from a later 650/750/550.

I also agree with ED, you probably need a new battery now that the old one was damaged by deep cycling, and you probably want to get a regulator/rectifier made for a KZ650/750. If you get a 3-phase stator, you will need a new 3-phase reg/rec anyway.

I could not find any info an a "Sparkx", but did find "Sparx". I assume that is what you have. The info I found was only for Yamaha XS 650's, though.

Reg/rec's for other bikes (with permanent magnet alternators) can theoretically work on the KZ, but a specific fit has less guess work involved.

Yeah, I was misspelling Sparx. Probably frustration and crankiness. I get that way when dealing with electrical issues. Sorry.

That was the answer I wanting to see, yet not wanting to see. Know what I mean? Now I won'y waste anymore more money or time buying parts I don't need or chasing phantom problems.

Finally decided to build my own ground up wiring harness this coming winter. Then no more wondering where this wire goes or why it starts out one color and ends up another. It will be rational to irrational brain.

Geez, this thing has been cut and spliced by so many PO's. Infuriating. It would probably make even you electrical geinuses pull your hair out.

Thanx again folks.

I hear ya. You can easily spend more time tracing out what someone else did, than just re-doing the whole thing from scratch.

Will all KZ650 charging systems interchange between all cranks?

I have a 1980 F1 engine fitted to a 1977 chassis. I also have a parts bike with what I believe is a B1 spec engine/alternator system. I do not know what alternator I have in my F1 engine, either, only that there is a B1 cover that's been modified. I suspect it's a newer charging system, though, but it isn't charging well enough so I want to fit the sustem from the parts bike instead.

Measured voltage today and got 12.9V idling and 13.3V at 4000 rpm. Not great but still a surprise to see the battery run down to 11.76V.

With the lights turned out, I got over 16V at 4000 rpm, starting out at around 13V at idle.

To me this indicate that I have too little amp from the alternator and a shot voltage regulator, but I'm not sure. Any tips?