Kawasaki KZ650 Rewire question

Hey Evan awesome blog n sites.

Question: I have a 1977 Kz650B bought “right”, $250, turning into cafe’.  Tore into rebuild and found wire harness to be pretty much a mess.  Bike ran okay, (as much as I could in the snow) but when I tore into the bike I ran into bunches of splices I have no idea what for etc.  Plus rectifier looks pretty well worn.  I found your other wiring diagrams online and had further questions.  I would like to eliminate the battery since I have a kick starter and going for the clean/light cafe’ look too.  Trying to keep it legal in Ohio so I’d need turn signals, high beam light etc.  But other than the those “bare necessities” I’d like to not do more than required.  I thought I read you mentioned the possible need for a capacitor if you eliminated the battery?  If so where do you put it and what rating?  Also do you have a recommendation for a regulator/recitfier to use?  Need to put any diodes anywhere?

Your 1977 KZ650 has a 3-phase excited field alternator which will not allow you to run without a battery. You will need to swap it for a 1978+ KZ650 single phase permanent magnet alternator. If you do that you can then run a capacitor in place of a battery. You’ll want a capacitor somewhere in the 50,000ud 16v to 100,000ud 50v range, it won’t matter too much as long as it’s a well made unit.

You’ll also need to be replacing your regulator for one compatible with the permanent magnet unit, and in turn will need a different rectifier as well.

If you want to stay legal then the above isn’t for you anyway. You won’t have good reliable blinkers because flasher units work best with the ballast of a battery, and you won’t meet requirements for having headlights and taillights being able to remain on with the bike off. You’ll need to decide what’s more important to you.

The simple solution is to just run the smallest battery you can find and leave it at that. A small sealed lead acid battery from an electronics supplier can be about the size of 2 decks of cards and will power everything normally (except the starter).

KZ650’s are great looking bikes in my opinion. I don’t think they need a whole lot of work to be cool. Here’s mine (it has the battery happy0158  ):


Kawasaki KZ650

Wow, thanks Evan for such a complete answer!  smile

Yea, I think I’ll go with your recommendation and leave the battery in the loop then.  You made my life much easier.  Nitro may be in this bikes future and a battery would be necessary anyhow then.  Found a great site from a guy named Burgerman  .

He builds dynos in England really lays out how to build a system if you ever want to read about it.   Don’t know but thought you might like this kind of stuff if you havn’t already found this guy. http://www.nitrous.info/motorcycle-nitr … system.htm

I actually had my local NAPA dealer (Still an “Old School” kinda parts store) locating a low profile battery that I think I can tuck under the rear plastic.

I found a Regulator/Rectifier at RegulatorRectifier.com

http://www.regulatorrectifier.com/catal … -Rectifier

Would this work with this diagram from your post? I would like to combine the two if possible.

http://cycles.evanfell.com/2010/03/simp … fe-racers/

No problem, here to help!

The regulator/rectifier unit you linked too was actually the one for the KZ750. Probably just a simple mistake, the one you want is obviously the KZ650 version.http://www.regulatorrectifier.com/catal … -Rectifier

If you’re looking to save as much money as possible you can get a single regulator or rectifier for quite cheap. Moose sells generic ones as well as a few other manufacturers. But the unit you linked to looks pretty nice.

Yes, my simple wiring diagrams will work for your bike, and virtually any other bike as well. It’s just the basic electrical components needed for a bike to run and have simple lighting.

I haven’t been to Burgerman’s site before but will take a look, thanks for the link.

I’m going to move my photo hosting site to a new server in the next 24 hours, it’s having some memory issues preventing large resolution photos from being processed properly. Will be fixed ASAP!

Cool on the correct part 650 vs. 750.  I can say that sites customer service is outstanding.  The guy was really trying hard to find the right part for me so I’d like to reward that.

I try and find a balance between being “frugal” on projects and doing the “right thing”.  Enhances the chances that next time a I need something they will be there for me.

Yea, I know some KZ pureist would probably like to hang me for cafe’ing this bike too.  It’s in pretty good shape, as yours looked really nice for that era.  I’ll post some pics once I can.  But even primo restored they ain’t worth nothing! sad , my VStrom while powerful and torquey is a bit of a “pig” sometimes and I wanted to try this project.  I live near a couple of tracks here in Ohio where they have classes etc.  Thought I’d might try one someday.

If ya ever need some farming or wine info. let me know maybe I can help ya there! big_smile

Have fun in Mech-key-co!  I once was in the back country at a farm village there on an agricultural leadership program, awesome “REAL” Mexican food and well when ya drink some local “Hooch”,  tongue WoW!  But we HAD to, otherwise we would not have been being “polite” 2 R hosts!! lol

Take care

Hey Evan I’m Back w/nuther KZ650 wiring question

I got the 650 Reg/Rec but again my wiring skills are better suited to houses and such.  I have your wiring diagram for custom motorcycles – chopper/cafe/rat w/Hans edited version and it’s getting me close but my reg/Rec has more wires?

I have the 3 yellow wires to the stator, 1 green to neg. , 1 red to pos., 1 blue to key/switch, but then I have a orange that it says is to go positive brush on rotor or field coil?  That’s got me? Instructions go on to say “For motorcycles with brushes in the charging system: the orange wire goes to the (positive) brush (non-grounded).  The (negative) brush must be grounded.

Project going well, I’d upload a pic but I’m not smart enough, I’m sending this from a new iPad I won and that is proving challenging enough learning apple-speak!



Evan Fell

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