Problems; Where to begin '81 KZ750 LTD

Hello, my name is Duke. I've had this '81 KZ750 LTD for about a month or so, and I just now found this website.. better late than never I suppose. This is my first motorcycle, I've ridden a few through my lifetime but never had the money to get one. The only way I even have this one is because the guy wanted a PS4, then PRESTO! I am a motorcycle owner like the rest of you!

Here's the rundown of what is going on with the bike. It has temporary turn signals on it, the guy I traded with said that ever since he put the temp turn signals on, the bike has to be "jumped" in order to start. So he jumped it, it ran, I rode it, everything seemed fine, just some sort of wiring trouble or something. I get the bike home and I take the battery out, which I was told was new. The battery levels were all jacked up, some were overfilled and some were underfilled, there wasn't one that was at the recommended level. On top of that, the sides of the batteries were sort of bulging out. So rather than try to salvage this battery, I just went and got a new one. Nothing fancy, just the Walmart "everstart" or "everready" batteries that they sell. SO, I get that home, levels at recommended fill, and all that great stuff. I hook it up, and notice there is an extra cable on the positive hookup for the battery. So I just took it off and hooked up the battery without it, just using the red and black + and - cables. However, that didn't work. The bike wouldn't start. So I found out, long story short lol, that that extra cable needed to be attached in order for the bike to try to start. So I hooked it up. NOW the bike is trying to start when there is no key in the ignition and the bike is in the off position. It won't start however, it just cranks over like its trying to but I guess it cant get gas or a spark? I don't know. I'm by no means a mechanic. So I put the key in and turned it to ON. The headlight came on and the lights on the tach/speedometer lit up. However, the bike wouldn't crank now. I had to turn the bike off, then while holding the "start" button and the bike trying to start, flip the key to on simultaneously, in order to get the bike to start. However, it started for a second then fell on its face and I couldn't get it to fire up again.

DOES ANYONE HAVE ANY IDEA AS TO WHERE I SHOULD EVEN BEGIN WITH THIS THING?

Thanks to anyone who actually takes the time to read this, I hope someone can follow what the hell I was trying to get across and point me in the right direction. Thanks again!

Welcome aboard! You need to buy a Kawasaki service Manual. They usually are available on eBay; just be sure to get one for your bike's exact year & model as there are differences. The back cover of each manual has a list of model covered within. Get the real deal, not a Clymer or Haynes manual. The manual covers everything in great detail, and you will need that info to get the bike sorted out and to maintain it. Once you get the manual take a look at the wiring diagram and compare it to the wiring on your bike to make sure a previous owner didn't screw it up. Good luck with your "new" bike. Ed

Welcome. Electrical issues are difficult to diagnose long range, but my first guess is that somehow hooking up the turn signals someone has managed to connect a direct live feed into the harness that is bypassing the ignition switch. This is likely why the battery has been going dead since they were put on. I would check how all this has been connected first and perhaps disconnect everything you see that is new or different from original. I'm not familiar with the 750LTD, but both my KZ's only have a two connectors hooked to the battery as stock., so I'm thinking your extra connector is why the ignition is "on when it's off so that the starter motor spins.

The wiring on the whole is pretty simple on these bikes, get a manual and follow the wiring diagrams, it's pretty easy to see where it all connects and the various circuits, a lot of stuff goes to the head lamp bucket.

I wish I could be more specific, but I think you just need to go through things logically so if you still don't get it fixed you can report back in away that others can keep narrowing things down and guide you towards the problem.

Welcome to the forum and congrads on your new toy

+1 on the shop manual. If you have very little experience with mechanical stuff then this should be your first stop. Once you get the manual you will be able to follow the trouble shooting guides and illustrations for all the issue you come across.

Running down electrical issues without the proper tools is also tricky. The manual will made some good suggestions I what you will need.

Did you properly service the battery before installing it on the motorcycle?
For one thing, it needs to be charged w a mc charger beforehand.
Motorcycle Consumer News - The Care & Feeding of Your Pet Battery .. . & ... Yuasa Batteries - Info section

Here's a site w a pdf manual & wiring diagrams. mbsween. bike-night. KZ750L3 . Scroll down & click "The Bible" link.
The manual is kinda poorly scanned, but it's better than nothing --- the bottoms of some of the pages are lopped off
Note: some of the wiring diagrams are mislabeled in the links: the 1981 Ltd is an H2, the 82 is an H3, & the 83 is an H4.

There are some color wiring diagrams in the Filebase here - click on Filebase above - including one for the 750 H2 which is the 81 750 Ltd. .... I think.

My 1980 750 E1 has 2 wires coming off the battery positive terminal. A fat one to the starter solenoid and a a red/white one to the main fuse . You should have at least the same and possibly an additional wire to an accessory line..

Regardless, it sounds like your wiring has been hacked up and maybe hot wired. You need manual, wiring diagram, a multi meter (digital) and lots of patience while you trace everything.

Turning key on should give you all lights

Remember, bike will turn over but won't fire/spark unless clutch is pulled in.

Good luck

Thanks for everyones replies, you've been a great help. I will track down a manual on ebay first I suppose and then go from there. I was going to just rip off the whole wiring harness and put in one of the motogadget m-units, does anyone have any experience with those? Or would I be shelling out $300 when I don't need to? Again, thanks for all your guys' help, I greatly appreciate your input and your time. I will check back in a day or two and let you guys know what I've come up with. or what else I've messed up lol. Thanks again everyone

No eBay APP ID and/or Cert ID defined in Kunena configurationReal quick if anyone sees this, is this the manual I need? I just want to be sure before I spend the money on it, thanks.

There is a build thread around here the member installed an M unit. May be able to search it.

www.kzrider.com/forum/4-electrical/59912...kz400-diagram#687435

No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configuration

3EyedDuke wrote: Real quick if anyone sees this, is this the manual I need? I just want to be sure before I spend the money on it, thanks.

Yes, that is the correct manual. The -02 on the end of the part number suggests it's the revised version which will include info for your bike. The base manual is for the 1980 model and you need the first revision which includes a supplement for the 1981 model year.

No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configurationThis manual shows the model application chart on the back cover.


Here's a later version for the 80-85 chain drive models. Kawasaki manuals that cover more than one year will have the main body of the book for the 1st year, then supplements for each successive year.


Just linked it to show the model application chart.