Kawasaki KZ650/Z650 B1 1977 - From the highs to the lows 

Just read an old thread over on KZ Forum, which may be relevant. Two issues causing problems. Guy added rubber washer to airscrew; New air screw O rings and screws set to 2 and 3/4 out finally fixed mine. The other guy had revs hanging, turns out the sliders were 'sticking', although the linkage snapped back the sliders had a mind of their own. Food for thought.

Hi Mark here it sounds like your starter clutch is on the fritz but they can do that with a weak or low battery also put fresh set of plugs in they really like good plugs and get a new battery it will make world of difference your almost there cheers mark

The infamous starter clutch slip. hope you are using Semi synthetic oil not fully synthetic. if so drain and fill with semi. These clutches are very sensitive. You can repair them with the sump off and sec shaft out. try also a booster battery to get more volts when cranking. Hope you get it sorted. Check if plugs are wetting up too. You will get there.

Keith, We’re all feeling your pain Bro’! At difficult times in life, it’s a good idea to re-think and go back to basics. OK, we know that most ‘Z’s supply a ton of gas/air when on choke, so getting it to ignite, should be straightforward if everything is working as it should. My plan would be: Replace each plug with a new one, check for a good spark and also do a quick compression test, while the plug is out. Check the voltage at the coils, should be close to battery voltage. Hook up a 100% good battery with enough cranking amps. Use jumpers to add another if need be. Be sure each bowl has fuel in it. I think you should keep the tap switch on, on your temp supply. (I did read that the temp’ supply should sit close to the normal height of the tank? Maybe relevant). Choke on, and it’ll fire up. If it runs, albeit badly feel quickly for which cyls are hot, then onto stage two, you can direct your efforts. Now if you have rigorously done the above, and it won’t run, something ain’t workin’ right, no shit, right! If the plugs are wet, then time to look at timing, the spark is either too weak or coming at the wrong time. If plugs are dry (I doubt this one) there has to be a gas into carbs problem (airlock?) as you’d expect some carbs to have gas, and fire. Hoping the next vid will bring good news. Good luck.

Check your spark timing. Sounds like the spark is over advanced. Also check the left points go to the 1 and 4 coil and the right go to the 1 and 3. Keep your great work.

Keith , I'm aware that when fuel taps are changed from vacuum type to gravity fed type you have to plug up the vacuum port on #2 carb. As you are temporarily using a auxiliary fuel tank ( gravity fed) you may need to temporarily plug port to get running properly.

Also the noise you hear is the starter clutch rattle

your chasing your own tail,NEW BATTERY,a squrt of easy start,put the air box back on,and take out the filter when you use the easy start,and she will run,and you said it the noise the starter clutch makes gos with a fully charged batter,just remember no bike will start if the battery is weak.

Needs a fresh battery, and stick a clean rag in the top hole of the airbox when trying to start it. Leave the petcock on prime while trying to start the bike. And fiddle with the choke while trying to start the bike. I’d try half choke with the rag in the top of the airbox.

One thing I noticed with my KZ650 is that it has a hard time starting with a weak battery. I once run my battery really low and a few days later the bike didn't want to start, but it cranked slowly. Once I connected my battery charger and gave it a boost, it fired right up. If your battery charger is capable of boosting, I would suggest you use that while cranking. As far as carbs, I think your air screws need to go 2 turns out or maybe even more, as I think you don't have enough air. The reason I believe this, is because when you installed the air box, which restricts air, the engine would not fire at all. Since you made no other adjustment to the carbs, and the only change that the airbox would provide is air restriction, it would suggest to me that your issue is with having not enough air for the fuel delivered.

It's doesnt appear to be turning over fast enough to draw well through the pilot circuit. Check the cranking amps on the battery. The book will tell you.

We still haven't seen how the HT leads are connected. Sometimes, You need to follow the wiring diagram, E-X-A-C-T-L-Y as it is drawn. But enough of that. It should turn over a lot faster than this. Put the airbox back in, and try with a fully charged battery. Use the choke, and clean and install the tank. I'm sure it will start again, in a state where You will be able to synchronise the carbs. Good luck! 😎

Keith Have you checked the plugs to see if wet? Plus do you have fuel mix screws front of carb bowls? If so they need unscrewed from seated , 1:5 to 1:8 out . Just a suggestion,

Hi Keith, my Z650 is a real bad starter too. Maybe its a weak spark. Check the voltage at the Low Tension side of the coils. Should be as near as to the Battery Voltage.

Check the regulator & stator to see if it’s holding a charge,it could even be that the starter clutch has come undone,

Keith, it looks like your fuel line is turned off in the video and you will need to turn the choke on if you haven't tried that yet. Also you have to have a fully charged battery. So close.

Hello, I can see what is wrong, you should have spark plug leads from left coil to 2 and 3, then leads from right coil to 1 and 4, good luck

Keith you know what you do to a lame horse don't you? Just trying to lighten your day, I know it isn't a funny situation, but again just trying to put a smile on your face. Just a thought but are you using your choke when spinning it over? Just a thought, this is a strange one mate, I would probably have my hair pulled out by now. I will be thinking about this and if something pops up I will get back in touch. Keep the faith man you or someone will come up with something.

It looks like you don't have the right cylinder head top for it. Your air cleaner box needs to filter out through that area.

How easy is it to turn the engine over. By hand with the plugs out and in neutral your engines not tightening up is it?

Have u got an oil pressure gauge r u getting oil pressure? If there’s a gallery plug undo it it crank engine see if you’re getting oil flow

It’s not spinning over properly battery sounds a bit stuffed u need plenty of cranking amps to get the starter clutch to engage the whirring will be the starter clutch not engaging properly

Don’t seem to go over very fast and the motor sounds tight to me don’t want to dishearten youkieth but dosent turn over fast enough

Hi Keith, did You check the compression? I looked at Your Video #57 where You only said, that You cleaned the valves. But did You also grind the valves (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HjX0fsvZ4tE.html at 2:25). If not, and the compression is below 7, that can be the reason for this bad behavior. Just an idea.

just get your self a decent battery and stop waisting time trying to start the bike with a battery in that weak state,as how can the bike fire there would be no spark at the plugs,you need over 13 volts,get it running on all 4 pots,and the motor will sound sweet and balence the carbs,as for the noise thats just a tired starter clutch,but one again with a new battery it will work better.