79 KZ650 SR - Starting and Running Problems

My low mileage 79 650SR starts really hard and will only start with the kick starter, won't even pop while cranking with the starter. No matter what, when it does start it idles with the choke half way on but doesn't take throttle without a bad stumble at least.. I had the carbs all apart and checked float levels, etc and all looks good. I'm wondering if there is an electrical problem and when he starter is taking current too there is not enough to go around ? If anyone has an experience with this or ideas I would sure appreciate your help. I'm soon gonna be too ld to ride this thing if I don't get it figured out soon.. Thanks, Tom

When you start the cold engine remember - choke on and do not touch the throttle. Your battery may be just a tad under-charged in which case it will spin the starter but not have enough ooomph left for the coils. This may be particularly true with your bike as I suspect the headlight is on as soon as you turn the key on. When my battery is not FULLY charged I use the kicker; it usually takes only a couple kicks at most. In fact, I nearly always use the kicker when the engine is cold; once it is warmed up the electric starter easily starts it. As far as the stumble is concerned, does this happen even after the bike is warmed up (say 3-5 minutes) and the choke has been shut all the way off? By the way, your bike is BEAUTIFUL!!! Ed

Thanks for the help Ed, I will check the battery, I kind of suspected some sort of voltage shortage. Even after it is fully warmed up it still needs the choke on to some point to keep idling and no matter what, it stumbles (nearly dies) when you try to give it throttle. I'm gonna go in and check the dwell, timing, etc. when I can find time and see if I can make it better. Thanks for the compliment on my bike. I bought one of these new and have owned three used ones counting this one. Life and family always came up with a reason why I had to sell them but I am really trying to hold onto this one. I have loved the SR's since I first saw one. Thanks again for the help, I'll let you know if I manage to fix it. Tom

Your description sounds like it's carb related to me, having to keep choke partially on when warm, has usually been carb issues on my SR
I've also never had an issue starting it with the electric start unless something else was amiss, such as something electrical that was out of order.
You may have more then 1 issue here
and That is an excellent looking bike
I also loved the look when I first saw one and have been riding it ever since...1979

Do this too:

Cleaning Motorcycle Electrics

Get some of the De-Oxit electrical contact cleaner and figure on spending a good day going from the front of the bike to the back. It’s a plastic safe cleaner/preservative. www.deoxit.com is their website.

On the older Kawasaki's, a majority of electrical connectors are inside the headlight housing requiring removal of the headlight,then the fun begins.

Do one set of electrical connectors at a time to avoid mixing up what connects to where. Usually disconnecting, spraying with De-Oxit and reconnecting is about all you'll need.

However, when encountering the green crud of corrosion, a brass wire brush may be needed on the pins you can reach. Some 400-600 grit wet and dry sandpaper strips rolled into a tube should reach the male and female pins in the more difficult to clean connectors.

Smoker’s pipe cleaners, cotton swabs and wooden toothpicks work as cleaning aids.

Really small electrical connectors may require the use of a welders tip cleaning tool assortment.

Most pins in the connectors are coated with a thin plating of tin, and others may be nothing more than copper or brass.

If moisture is added, the resulting corrosion lowers the voltage/current being carried causing dim lights, slow engine cranking, slow turn signal responce and lower input voltage to the ignition coils resulting in weak spark.

The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start.

Usually a spritz or two with actuation of the switch is about all needed for these switches unless corrosion is detected and then careful disassembly is required.

The ignition switch may or may be not sealed to allow spraying the internal contacts. I urge caution if attempting to open this up as springs, and ball bearings may fly out never to be seen again!

If your bike has the older style glass tubed fuses, I suggest replacing them as vibration can cause internal failure. AGX is the type used, and most auto parts stores can get them for you.

Clean the fuse holder clips, looking for signs of overheating(discolored insulation, signs of melting), I use metal polish on a cotton swab, followed by spraying another clean swab with the De-Oxit and then rubbing the inside of the fuse clip.

Each "Bullet Connector" will have to be sprayed to ensure good connectivity, especially the ones going to the energizing coil of the starter solenoid.

The alternator output “Bullet Connectors” are usually behind the engine sprocket cover and will need inspecting and cleaning too.

The turn signal light sockets will benefit from a spritz from the contact cleaner along with the tail light/brake light socket.

Some brake light switches can be sprayed on the actuating rod, with the spray running down inside to the electrical contacts, others may be sealed requiring replacement if the switch is intermittent in operation.

I think I've covered about all of the electrical systems on the bike.........


I used the De-oxit D-5 spray on all the electrical connections of my 78 Kz1000 that had sat for twenty years .

When I parked the bike in 92 I was starting to have troubles with some of the electrical system,
but after pulling everything apart and giving it a spray , reconnecting the connectors and working them back and forth a few times, then gave them another shot of spray to wash them off before the final reconnection.

Everything still works perfectly and has for over 7000 miles this year.

I am extremely happy with the results , a lot of the connectors were green when I started and after the cleaning they looked new ( shiny gold )

I found the Deoxit D-series, D-5 spray in a 4 oz can at a big electronics store called Frys in Illinois,
don't get the small cans at Radio Shack , they are different and meant for computer type stuff.

store.caig.com/s.nl/sc.2/category.188/.f

Trust MFolks , the guy's a true rocket scientist and really knows what he's talking about

JD






Why WD-40 Should Not Be Used On Motorcycle Electrical Items.

For many years, I was proponent of the use of WD-40 on fuse clips, fuses, switches and connectors. After hearing of other peoples experience with intermittent and sporadic activity, I shrugged it off as maybe they did something wrong in the application of the product.

It wasn’t until the time I rode my 1982 GPz1100 B2 model to downtown San Diego that I encountered the problems others had gone through.

After concluding my business downtown, I walked to where my bike was parked, turned the key to unlock the forks, and prepared to start the engine. The key was in the "On" position, yet I had no lights in the dash panel, the fuel pump was not running(I have FI), and the horn and tail light were not working.


Stumped as to why nothing electrical was happening, I remember my earlier conversations about how WD-40 will over time become a non-conductor(more like an insulator). I had some pieces of 400 and 600 grit sandpaper in my tool kit and with them was able to scratch away the coating from the WD-40 on the fuses and clips.

After removing the insulating film, the bike started and ran like it should. Since that time, I’ve told people about the problem with WD-40. If you must use a contact cleaner, I recommend getting some "De-oxit" from Radio Shack Stores or any good electronic supply store.

Thanks a lot for taking the time to reply. I am have an offer for the bike and thnk I will sell it since I just do not have time to chase its problems. Thanks again, I appreciate it. Tom