Idling poor/ misfiring

My issue is that the engine doesn't idle well, I need more than 1/2 choke to keep the engine alive, and I hear the occasional pop from misfiring as far as I know.

I really don't know what is causing this issue; carbs, engine in general, or something with the electrical system.

As far as I am concerned it has to do with the points the engine timing cause it's been a year since I've had the bike, only a few days since it is all put back together after a full engine rebuild, bored, new pistons, new valves. ----Points haven't been adjusted, timing hasn't been looked at all yet---

The carbs were cleaned rebuilt and sync however the shop admitted to the fact that the carbs weren't idling well on their test bike but it would run well, red-lined beautifully. This gives me reason to believe it isn't so much the carbs fault as they are just causing the issue to be magnified.

Any suggestions on why the bike would idle so poorly? Get the points and timing sync'd right and just expect it not to run perfectly for a while since it was so rebuilt just recently and barely run?

This is the perfect symptoms of clogged jets. If the shop admitted to them not working FLAWLESSLY I would suspect them to be clogged. Simple things to check are points adjustment, leaky manifolds and missing vacuum lines/plugs. WHen dealing withpoints there is no such condition as "close enough". They must be EXACTLY within specifications. We've all heard Grandpa or Farmer Smith saying they always just folded a match book in half and used that as a gauge. That's fine for my 1965 Ford truck when it quits on an old dirt road, but not these bikes. Good luck, but I would lean towards the carbs being dirty or a couple of bad intake manifolds. I've never seen the choke improve bad timing.

I'd check the charging first, these old bikes need a steady souce of power to run right. To test, read this:
www.electrosport.com/technical-resources.../fault-finding-guide

A low voltage to the ignition coils will result in a weak spark, having you start in the endless circle of carb adjustment,jet replacement, and moving the adjustable needle jet up and down.


Testing Kawasaki Ignition Coils For Input Voltage

When voltage testing Kawasaki Ignition Coils, the following needs to be done:

1. Remove the fuel/gas tank to access the coils.

2. Fully charge the battery.

3. Using a multimeter, set it up for VDC(Volts, Direct Current), range of 20.

4. Turn on the ignition switch and the run/stop switch to “Run”.

5. Put the multimeter’s RED probe on where the red or red/yellow wire goes on the ignition coil.

6. Put the multimeter’s BLACK probe on either the battery Negative(-) post/terminal or a good frame ground.

7. You should be able to see battery voltage at the ignition coil connection, but this depends on the current draw of other items in the same circuit.

8. If the tested voltage is down to 8-9 volts, you probably need to clean the many and various electrical connectors.

9. To check the spark output at the sparkplugs, use these:

Ignition Spark Testers
www.lislecorp.com/divisions/products/?pr...ivision=1&category=8
www.lislecorp.com/divisions/products/?pr...ivision=1&category=8 Instead of grounding the sparkplug with the sparkplug wire attached, looking for a spark. This method puts the IC Igniter and ignition coils at risk of failure due to high currents, and possible internal shorting.


Cleaning Motorcycle Electrics

1. 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. It can be purchased at most Radio Shack Stores or any electronic supply places. Or use any plastic safe electrical contact cleaner(NOT WD-40 !).

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

3. 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.

4. 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.

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

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

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

8. 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.

9. The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start. The older Kawasaki’s have reports of the soldered connections crumbling, if your bike has this problem, just ask, as I’ve got a repair procedure for this.

10. 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.

11. 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!

12. 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, along with boating supply stores.

13. 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.

14. All battery cables must be clean and tight for maximum current transfer. Check the cables going from the Negative(-) battery terminal/post to the engine mounting bolt

15. Also the one going from the Positive(+) terminal to the starter solenoid and from there to the starter motor.

16. If any battery cable feels ”Crunchy” when flexed, replace it as possible corrosion is inside the insulation. Inspect all heavy duty battery cables and the smaller wire terminations(Bullet Connectors), for failed crimps, and those used in the electrical connectors, as they can fail over time.

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

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

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

21. 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.

22. Some people put the Di-Electric Grease on cleaned terminations/connectors, I don’t, as I’ve read/heard it can cause problems when it gets hot, actually insulating the connections, so the choice is yours to use or not.

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

“I spent a weekend going through every electrical connection and switch on the bike with a little scotchbrite pad and DeOxit - what a difference! Everything was brighter, gauge backlights, indicator lights, turn signals, I was getting a nicer spark, it fired up quicker, etc. Well worth my time. WELL worth it! “

From a forum member at www.kzrider.com

Thanks for the replies, I'll look some of this.

Extra info:
Bike: 79' KZ1000 LTD
Carbs: Mikuni VM29 smoothbore (as far as I know)

I saw the carbs run on a test bike at the shop this is what was said:
They run beautifully, redline perfectly, idling isn't so great; put 6 hours in and it either idles really low and will shut off or idles high.

I put them on my bike and I need 1/2 choke or higher to get the motor to even start, and after running for 20 minutes or so I need to keep it at 1/2 or higher choke or rev the motor every couple seconds or it dies.

Motor points have never been checked so I'm gonna go with that first, then new air filters, clean electrical connections, then finally go into the carbs more and clean them further.

---

Extra question: If the carbs I have are in fact Mikuni VM29 smoothbore, is there anything I need to keep an eye on or be careful of? The one thing I am 100% sure about is the fact the that guys at the shop said these are pretty delicate even for carbs and were often broken because people didn't realize how delicate they were.

29 smoothbores should have a plug on the bottom of each float bowl to access the main jet without removing the bowls. My money is on a lean condition. What was the exhaust/air filtration combination on the shop's test bike as compared to your bike? You may well just have jets which are too small for your configuration. If you have a 4 into 1 pipe wih pod filters as compared to a stock exhaust on the test bike you are probably too lean. Just food for thought.

If the carbs run great past idle then it will NOT be your main jets leave them alone. You idle circuit is clogged or gummed up. And no running a can of carb cleaner in your gas will not clean out the carbs.

The engine they were running I believe was a stock 1015cc engine, in comparison to the bored 1100cc(ish) engine I have, they were also using a replica stock pipe or stock pipes in comparison to my kerker 4-1 exhaust as far as I remember. Would "lean conditioning" really make it so the bike won't even idle at all?

How's the sparkplugs look? White is too lean, Black too rich, but a light tan is about right. This will be seen on the center electrode of the sparkplugs.

To really see how the engine is doing, do a plug chop(meaning bring along the sparkplug changing tools and go for a ride). This is usually done on a not well traveled road, so you get up to about 50 mph, pull in the clutch & kill the engine(using the run/stop switch) coasting to a stop. Find a tree for shade if possible & let the engine cool a bit before removing the sparkplugs.

This method will let you know how the main jets are working.

I've actually just recently replaced the sparkplugs, and the sparkplug caps or boots what have you. I snipped the wire and attached brand new NGK spark plug everything. I cleaned up and adjusted the points and the engine sounds quite a bit better. Not perfect yet, still needs some choke to stay running, and the initial acceleration from a stop is a little chunky however after that it seems pretty good. I think the fire timing might still need fine adjustment, and I'm gonna have someone look over the carbs to see if they are as good as they at least need to be.