Losing power 78 750B twin.

Rode my bike to work this morning. Everything was fine. Sat all day. Got on this evening to ride home. Started up just fine (kick start only, cafe bike) and started up. Headed to get gas had some issues where the lights were cutting out and losing spark. Came back died came back died. Got some fuel, headed out dying coming back died came back. Anyway it did this a bunch till I finally got somewhere I could park it.

So, I'm thinking either stator, points, or some kind of wiring issue.

Voltage regulator as new last Sept. Battery was new Jan/Feb


I'm at a loss here, please help.

If lights and engine flickers, I would suspect a poor ground connection first of all. If battery goes low, you will lose power and it will run worse and worse under load, but it's an even process.

Headlight and ignition (2 separate circuits)cutout indicates short/interuption between battery and fuse box(starter relay post if you did not remove it) main power feed or power from ignition switch to fuse box or loose ground wire.

Make sure you have 14V (+/- 0.5V) at the battery when revving it to 3k RPM. If not, your charging system is not working and you are running the battery dead while you ride.

Ok, turns out that on of the stator mounting bolts inside the stator cover came loose and then fell out inside the magneto. I suspect that the bolt messed up the stator. Only getting between 8.5-9 volts from the charging system while running. So I need a new stator.

My new question is, what are my options? Which different years and bike sizes can I get what need from?

Cdiver wrote: ...Which different years and bike sizes can I get what need from?

Lots of good info on kawasaki.com, including parts diagrams, part names, part numbers, models sharing same part, availability, etc. Here's a link for help with navigating the site and finding information.
kzrider.com/index.php?option=com_kunena&...w&catid=13&id=376734

Good Fortune!

78-80 for sure will interchange, I don't know about 82-84.

I might have a spare.

Ok, I changed the stator (used from Bent Bike in Lynnwood, Wa). Had the battery recharged and tested. Started up and ran fine for about 10 min. Got on it to ride. Ride about 50 yards and it stalled again. Still doing the same thing. I checked the battery at idle Nd it was at 10 volts. Rev it up and it goes to 11. What else should I look for? My KZ is kinda chopped. Not speedo, tach, starter, a few fuseable links and a bunch of wires. Not really a fuse box. Tomorrow I plan on going thru all the wiring and checking it. I could have gotten a bad used stator. Just not sure. How do I test to see if the stator is any good?

Please help.

For all who don't know. Probably the great place for getting any used bike parts in the country is a place called Bent Bike. They are in Lynnwood, wa. They can kinda be pricks sometimes, but they have an unbelievable amount of old bike parts. Stuff you just can't find anywhere.

Here's a good troubleshooting procedure: www.electrosport.com/technical- resources/diagnosis-center/fault-finding-guide

Ok. I'm still having issues. Replaced the stator with a used one. It puts out around 50v at idle and 80v when reved up. So I'm pretty sure it's not the stator. Like I said before the RR wasnew as of last Sept., not sure if it's the problem, but I'm going to test that next.

Any other suggestions? Like I said before my bike is pretty chopped, no tach, no speedo, no starter, no main fuse box. Not sure if there ever was one. If so it was gone when I bought the bike. Please help. I miss riding my bike.

You are not getting power to charge the battery and run the bike. It's a really simple sustem:

Dynamo (stator)

Rectifiers/regulator assembly

Wiring connecting pieces



Checking the open circuit voltage from a stator does not tell what it does under current load.

Sounds like maybe rectifiers or regulator? I realize they are "new' but still sounds like it.

Cdiver wrote: Ok, I changed the stator (used from Bent Bike in Lynnwood, Wa). Had the battery recharged and tested. Started up and ran fine for about 10 min. Got on it to ride. Ride about 50 yards and it stalled again.

As collateral damage, sounds like the battery may be hosed or weak from over discharge. A fully charged battery should run the bike for a lot longer than ten minutes before collapsing. Running it down may have killed the battery's capacity.