82 750 Spectre FUBAR? Carbs, plugs, starter & more

Hi I am new to this forum, I come to you from kawasaikimotorcycle.org My name is Dan I just bought this 1982 KZ750N Spectre two months ago, my first bike.

I have been having a lot of seemingly minor problems with this bike but I cant seem to figure them out. In the past month it has gone from not charging to over charging to seems like its working. I have also changed the oil and filter. The battery is new. Now it doesnt want to start when its hot. It starts fine cold with the choke on, then as it warms up itll start with the choke off or 1/2 on but not fully on. Once it is hot it wont start (consistently) with the choke in any position. I was also having a problem where it would stall as I slowed down to stop (mainly when I pull the clutch and it goes from 6-7k rpm to 0, it seems like it just falls to low and shuts off; I think it might have stalled only when the clutch is grabbed) either way I adjusted the idle knob under the carb and mostly fixed this problem. Heres the story (starting after I adjusted the idle): I start it cold, let it warm up untill the choke is 1/2 off and killed the engine. It'll restart with the choke off or 1/2 on but not on. It starts to I take it for a ride and all goes well, idles fine, stops fine, feels great, untill one red light. I feel the rpms drop and its at like 600 on the verge of stalling, I pull the throttle and turn up the choke and it zooms to 7k, when I released the gas it stalled. It wouldnt start (I believed I flipped the choke on) so I ended up pushing it for five blocks trying to pop the clutch, eventually it worked and I drove it home with the choke 1/2 on. When I got home I turned it off and tryed starting it with the choke on, no go. Tryed with it off and it did start. I killed it and tryed with the choke off again and it wouldnt restart. I pushed it in the garage and took the tank off. Heres what I plan to do, but I need help and/or advice on what else needs to be checked.
- I have gotten new spark plugs but I cant get two to go back in
- Rebuild and resync the carbs (how do I resynch?)
- Check the valve clearances
- Renew the air filter
- Check condition of hoses and wires, clean connections
- Put it back together and hopefully have an A+ machine
- It was having some electrical issues, I believe I got the thing charging but was only able to test it once or twice before being distracted by these new problems. Therefore I wonder if it could be the starter or it not getting enough power. How can I check this?
- What else should I check?
- Stay tuned, I will have many more questions as I start this project.

Complicating things, I ripped the kick stand out of the frame so its leaning against the wall. I ordered a center stand from ebay, should be here soon.

it sounds to me like you definitly need to go into those carbs and also pull the petcock out of the fuel tank and check out the filters those carbs definitly sound like they need to be cleaned properly that should cure most of your problems. what is up with the spark plugs that you can't get them in or out.

I am having trouble getting two back in. They turn three or four threads deep then stop. They came out fairly easy.

sounds like they are cross threaded you will need to get to a tool supply place and get 14 mm spark plug rethreader and try to clean the threads up when you get it and are going to use it you will need to put a fair amount of grease on the rethreader to keep stuff from falling in to the cylinder also it's a good idea to put anti-seize on the threads of the plugs when you are in stalling them so this doesn't happen again.

i had the same spark plug problem as you recently, and did exactly what timebomb just recommended and it worked great.

Sparkplug hole's female threads inside engine head are probably cross-threaded at beginning of threads. This usually results from careless sparkplug installation where the soft aluminum female threads are mangled by being cross-threaded with the steel male plug threads.

Attempts to re-thread by re-tapping or using a common thread chaser sometimes further damage the threads. Because alignment with the "good" threads must be perfect before re-cutting the damaged area, which alignment is often difficult to accomplish. Might get lucky, but might not.

The safe and sure method is using a reverse-thread tool, aka back-thread tool, which starts the re-threading procedure by first engaging the undamaged threads at the deep end of the sparkplug hole and working upward on through the damaged area and out the head.

This is the reason why sparkplugs should always be installed by first using only the fingers (never a socket or wrench) to hold the plug and deftly turn it to positively and unmistakenly engage the female threads, a turn or so, before applying any torque.

Good Luck!

Thanks guys. Since these spark plugs are on the side of the bike leaning against the wall I am going to wait for my center stand to get here so I have enough room to work. In the mean time I just took out my carbs. The picture may not be necisary and I hope you can tell me this is normal but of the four vacuum hose connectors, one has a rubber cap and was not connected to a hose. www.mypicx.com/06212009/carb/ What does this mean?

dcv83 wrote:

Thanks guys. Since these spark plugs are on the side of the bike leaning against the wall I am going to wait for my center stand to get here so I have enough room to work. In the mean time I just took out my carbs. The picture may not be necisary and I hope you can tell me this is normal but of the four vacuum hose connectors, one has a rubber cap and was not connected to a hose. www.mypicx.com/06212009/carb/ What does this mean?

Am thinking the epa paraphernalia uses two vacuum nipples, and the vacuum petcock uses one vacuum nipple, which leaves the one vacuum nipple unused and supposed to be capped (plugged).

Good Luck!

The manual says that it is not needed to seperate the carbs unless attention to where they connect is needed. I do not know the benifit of checking this, or the extra work/risk associated from disconnecting them. I was wondering what people usually do or what you thought. Should I clean them in the bracket or take them off?

dcv83 wrote:

The manual says that it is not needed to seperate the carbs unless attention to where they connect is needed. I do not know the benifit of checking this, or the extra work/risk associated from disconnecting them. I was wondering what people usually do or what you thought. Should I clean them in the bracket or take them off?

Manual is correct. Separation of carbs is usually not required unless needed to address a fuel leak in the connection between carbs, such as replacing a fuel pipe, or wrapping it with teflon tape for a snug fit (white will work okay but yellow is better due to higher fuel resistance), or replacing an o-ring on the connection.

Good Luck!

Ok done the cleaning: heres the news, I had...
1 visibly clogged jet
2 clean float chambers
1 semi dirty float chamber
1 float chamber that looked like a lolli-pop exploded in it
3 stripped screw heads
and 1 bad o-ring
I have yet to put it back on the bike as my book said nothing about this: www.mypicx.com/06222009/what/ WTF is that? I did not clean it but it is easy enough to go back and spray some carb clean through if necisary.
Its my day off and I still got some day light so I am going to tackle the valve clearances. And use some touch up paint to make the carbs look nice before I put em back on... carb clean is some grade A paint remover...