more juice for my kz650

Hey all,

I just added a wideband o2 sensor to my bike, only to find out it is not working so well. My friend swapped it with his known good unit and there were still problems. When we hooked it up to a car bettery for power all was good. This led us to think that it is the weak charging system not producint enough amps to keep the o2 sensor hot.

The end result is me looking for more power from my charging system. I have a 1977 kz650 c1, it has (as far as I know) all the stock parts except the rectifier; it was changed for a solid state aftermarket unit as the stock one was burnt up.

What are my options?

What should I be looking for?

Does anyone make a high output alternator?

I am fairly sure I am losing alot of power due to old wires and corroded terminals. I have tried to clean the terminals before with contact cleaner but have had no better results. When I checked voltage for the coil mod, I was only getting 7 or 8vt to the coils.

Any help is appreciated. I am about to pack the bike up for a year as I am moving away; and I would really like to make everything work before leaving. Thanks for reading!

I don't get on KZr as often as I used to so forgive me if I missed something you may have posted in another thread, but why are you trying to run an O2 sensor on your bike?
Fuel injection conversion?
Trying to achive a more emission-friendly bike? :blink:

Using the Kawasaki factory shop manual you can check alternator output and the various other components of the electrical system. If you don't have the manual yet you can pick one up one eBay pretty cheap, just be sure to get the correct one for your year/model. This will save you $$ in the long run as you won't replace good parts (or damage them) in trying to track down the problem. In any event, I would start by checking alternator output and (if not already done) installing a fresh battery, then check components from the alternator through to the spark plugs until you find the weak link. Ed

I installed the o2 sensor to help with carb jetting. I am really sick of the guess work and some hard numbers for different rpm ranges will make it alot easier. Shooting for around 12.5-13.5 ish getting 9-10 at idle and 14 -15 around 3/4 throttle, so now I have some real data to use when making jet choices.


I do not have the service manuel, I have a clymer book which is generally pretty useless. I will check it for fault finding procedures, however I get 14v at the battery when the bike is running at around 5k. I know the rectifier was bad when I replaced it because it was a melted mess.

The bettery was new at the start of the season.

more info for clarification, the o2 sensor does work sometimes, but if the bike idles for a few minutes it begins to flash (i need to check with innovate, but i think that is caused by the o2 sensor cooling and tripping an error)

www.electrosport.com offers new overwound stators that are supposed to produce more output at lower rpm's than stock.

that stator would probably do the trick, execpt they do not make it for the 1977 650's infact the only kz650 it is listed to fit is the 1981-82 CRS, however that stator is actually a suzi stator that "fits" the crs.

What would it take to change my charging to the crs charging system?

Thanks for the help!

Any more Ideas??

ok I think I am in luck,

according to this thread

kzrider.com/index.php?option=com_kunena&...d=4&id=188221#188529

the 1977 system is a 3 phase electromagnet system (I knew this)

and the 1982 system is a 3 phase perm. mag system ( i did not know that)


It looks like the system electro sport is selling is for the 3 phase (1982) system. So if I switch the stator and rotor, my reg and rectifier should still work as they are built for 3 phase... right?

I know nothing about the black magic of electronics so please fill me in...

I believe someone over at www.wgcarbs.com forum did just that modification.

hardr0ck68 wrote:

It looks like the system electro sport is selling is for the 3 phase (1982) system. So if I switch the stator and rotor, my reg and rectifier should still work as they are built for 3 phase... right?

Not quite - the ´77 650 alternator is an excited field alternator and uses a separate rectifier and an adjustable electromechanical voltage regulator (basically a coil and two sets of breaker points) that works by interrupting current to the field coil when stator output goes above a certain level.

The KZ permanent magnet alternators use a combined reg/rec and the regulator works by shunting excess voltage to ground. (As far as I know a few models w/permanent magnet setups do use separate reg and rec, but the regulator still works this way).

Two different principles, so in order to make the 3-phase Electrex stator work you will need a permanent magnet rotor/flywheel and a 3-phase combined reg/rec, preferrably with 6 wires: 3 yellow stator wires, black/yellow ground, white or red/white output to battery and a brown voltage sense wire.

I have an Electrex stator in my ´77 650 w/´79 D2 engine, let me know if you need more info.


Edit: Dave Sloan did the same upgrade as I did and made a write-up about it, here's a link: CLICK