20 Most Recent 1977 kawasaki Z 650 Questions & Answers

Swap the coils around the opposite they are now, 2 and 3 to the 1and 4 coil and vice versa. If now 2 or 3 act this way it's the coil, if it's still the 1 and 4 it's a grounding or plug or ignition module. I would start with the flip first and see what you learn. The coils are the same just split into two different firing signals. So that should tell you a lot

it is probably too wore out to crank the engine. replace brushes and bearings or find a new starter.

Cycles Unlimited, Decatur, Al. should be able to get it for you. #256 - 355 - 1459.

Garnet Red Candy KC-16-201

Have you tried getting help from the guys at the KZ Rider Forum? Home KZrider com

the #should be right behind the front forks on frame

Pull the spark plugs and see if they have a black sooty coating. Sounds like a too rich condition.

Prob bad plugs, or carbs need cleaning. Timing not usually adjustable..

It sounds like something may have shorted, come loose, or burned out.Tracing where this is will take time and a multimeter to test all connections.

Check the float level in the carb. If the fuel level is too high it can flood the cylinder.

2 and 3 run off the same coil which sounds suspiciously like a coil failing.
What does the dealer do to make it run for a day? like putting new plugs in


If the carbs are not flooding and have beeen properly jetted they shouldnt cause a problem.
30 year old bikes dont often have genuine mufflers on them, so they need jetting to suit
If the carbs are standard I wouldnt consider changing them.
Standard carbs work best with a standard air box and filter.
Make sure the fuel tap is working correctly(no flow unless the engine is running) in case its sucking fuel down the vac line.

Don't go lower than 2 inches, this height is perfect, its what i use for cafe racers i have built.

hi go to the other side panel take it off and check the condition of the rectifier its a finned alloy
component and check for heat damage melting of wires etc if there is its toast find a replacement
I have seen these catch fire
its purpose is to turn three phases of ac electrical charge from the alternator to one dc charge
to the voltage regulator so could be the source of your trouble if it has a dead short
the bad news is that this has happened so often on this model of bike you will have trouble finding a good one to replace it with avoid patern replacements as they tend to be very unreliable
honda cb250 rectifiers are a lot more plentiful and can be modified to fit

I had a similar problem with Yamaha, they did not have codes, if you take a side cover or similar with required color to a paint shop they can match it and give you a code.

Try re-installing the points , it is common for points to short. Pull a plug and check for spark first (both sets of points). You can check for fuel in the carbs by opening up a bowl drain screw and seeing if fuel comes out. If you have spark and fuel in the bowls you may need a carburetor cleaning. Poor spark can also be caused by bad spark plug caps on the wires. Typically you can unscrew the cap from the end of the wire. If it OHMs out higher or lower than 5000 replace them . You can get NGK caps for about $5 each.

they are the float bowl drains. You use them to empty the float bowl of gas ( water, gunk, debis). there is a screw on the bottom that acts as a valve to allow gas to flow through the hose attach fitting.

Adjustments that you can make from outside the carburetor:
1) Synchronizer screws balance the carburetors for smooth performance and idling. 2) Idle screw (throttle stop screw) adjusts the speed of the idle. 3) The idle fuel/air screw adjusts the idle mixture. This is only at idle and does not effect anything above idle. Another method to adjust it: turn the fuel/air screw in and out until you get the highest idle speed. Then lower the idle speed with the idle screw and do it again until you get the best idle. The air screw can be located in a variety of places on the carb. On some models it may have a cover over it to keep you from messing with it. You will have to drill it and then pry it out using the hole you made. It may be illegal for you to do this, depending on where you live.

If you can't get it to idle, or rather the idle stays real high then drops off and dies, check for an air leak. Spray starting fluid, WD40, brake cleaner, carb cleaner, etc... on the manifold, carbs, air box, vacuum hoses, and petcock to see if the revs change. If they do, you have a leak. If your valve clearances are too tight, it will also effect the idle.

You can make your air/fuel mixture a bit richer or leaner by moving the carburetor needle clip up or down. Move the clip down a notch to raise the needle, to richen the mixture. Move the clip up to lower the needle, to lean out the mixture. The needle is located in the throttle slide. Air & Fuel Passageways: Trace and learn individual fuel and air circuits from beginning to end. Machines can only drill straight through the cast passageways. To change direction, another angled passageway must be drilled. The union is plugged with a brass or bronze bead. Inspect and clean each passageway with spray cleaner, brushes/pipe cleaners/etc, and compressed air. Remove any discoloration and debris. Look for spray cleaner to exit from one or more passageways. pilot fuel mixture screw or a pilot air mixture screw. Both types of screws are almost always covered by a plug from the factory. To get to these screws, you must drill a hole through the plug with a small drill bit. You must not keep drilling once you get through the 1/16" thick plug because you will hit the mixture screw itself which is underneath. There is a bit of separation between the plug and screw. To ident which you have, just look at the location. The pilot fuel mixture screw is located on the BOTTOM of the carb toward the intake side. On most CV type Kaw KZ carbs it will be located on the top but in either case, will be located just behind (toward rear) of the intake plenum (the intake tube). There will be a VERY small hole in the intake plenum and the jet needle can stick up through this hole. The hole is pin hole sized. The fuel mix screw on KZ type CV carbs will seat in a hole at the top of the plenum tube. Any type of pilot fuel mixture screw will have a very sharp needle end. This is because the hole it sits in is so small. Unfortunately, these screws are prone to breaking off at the tip because they hang in the hole. Some aftermarket pilot fuel mixture screws just won't work well because the needle tips are not sized quite right and they won't seat. If you tighten these screws, the tips WILL hang and break off. Be gentle with pilot fuel mixture screws. The pilot air mixture screw is up on the top/side of the carb facing toward the side of the bike and these are mainly on the round slide (non CV) type carbs. To get to them, you also drill the plug out. These screws control the amount of air that is mixed with gas in the pilot circuit and are generally blunt. They won't break but if you overtighten, they are brass, can gall and will stick. If they stick, you will have a heck of a time removing them because they are typically recessed and the slots on these screws really want to strip. Removing striped pilot air mixture screws is a lot of fun and requires special tools. They definitely are hard to drill out and not mess up the thread inside the hole. It isn't really possible to guarantee 100 percent a stuck pilot air mixture screw can be removed without ruining the carburetor it is in. If you have slots that are a bit stuck-up, REMOVE the them and cut some deeper slots and clean the thread with a wire brush (on the screw) and you might want to clean the thread in the hole as well. Take care as this thread is NOT the same as on case bolts and such; it is fine metric thread.

Last note, if you are unsure if you have plugs over the pilot air mixture screws, NOTE CAREFULLY if there are small round balls cast into the place where the plugs would normally be. If there are, there are not likly mixture screws beneath and drilling will reveal an empty passage with no thread. You will end up needing to cap this hole again with JB Weld. how to tune these air mixture screws, first seat them gently. They typically are pretty robust and will not bend or otherwise be hurt if you seat them hard since the ends are blunt. Make sure you have springs in there or they will vibrate loose! Then turn them out 1.5 turns or 1 3/8 turns or 1.25 turns . Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

A stuck or bad float is the problem. If the float develops a pin hole it will fill with gas, no longer float, and cause the problem described. The float shoul be light as a feather & with nothing inside it. More likely is that the float is either stuck open or a bit of trash is causing the float needle to be unable to close fully. When you rebuilt the carbs, you did put the float needle back in each carb didn't you? Please rate my answer. Thanks.

Replace the pilot and main jets then really clean the carbs soak them in a good carb cleaner. When you re assemble the carbs make sure you have the air screws turned all the way in then one full turn out start from that setting.

It should have the same wires as the original unit, the 3 yellow wires will be the 3 stator wires