TOPIC:

The bike is a 78 kz1000a with 30k kms. It's new to me just last month.

So far I've put new rear brake pads in; rebuilt rear master cylinder; new plug cap on #4.

I just finished rebuilding the carbs with a kit I bought online - new gaskets, jets, float needles, etc.

This afternoon I put it all back together and got it on the bike. She fired up right away. I let it idle for 10 minutes or so. Shut it off for a few, then ran it again for about an hour around my neighborhood. Near the end of the ride, when it tries to return to idle in 1st (stop sign for instance) it will stall out. The it'll take a bit of cranking to get it fire back up. Sometimes I had to twist the idle adjustment to get it going, then turn it back to normal idle once it was running.

After I limped home, I tinkered with it in the driveway. In neutral, I could get it idle around 1200. But when I pulled the throttle, it would race up to 3-4k and not return until I twisted the idle adjustment.

Also, if I pull the choke, it'll stall out.

Any thoughts?

I haven't sync'd the carbs - I'm not sure if that's beyond my capabilities.

Welcome aboard! You should check the carb holders for leaks. If they develop tiny cracks in the mating surfaces between the holders and the cylinder head they can cause those symptoms. These cracks cannot be seen with the carb holders in place. I suggest you try the following. Get the engine warmed up and temporarily set the idle as low as possible without killing the engine. The lower the better because with the idle very low the slides are about shut and the vacuum inside the carb holders is at its highest. Then spray carb cleaner around the carb holders, especially where they mate with the cylinder head and where the carbs attach to them. If the engine dies or seems to react to the carb cleaner, you need to replace the carb holders. Bad carb holders can cause some erratic symptoms because the amount that they leak can vary as they get hot. The problems are noticeable at idle but generally don't have much impact when riding because the throttle is open. If you find you need to replace the carb holders post that here before trying to remove them and I can give you some advice that may save you a LOT of problems by reducing the odds that you will break or strip a carb holder fastener.

As far as syncing the carbs, you can do it because it is actually quite simple, but you must have a decent carb sync tool or proper set of gauges to do it. Ask if you need some advice on a good tool.

The link below has some other info that might be helpful if you haven't already read it. Ed

kzrider.com/forum/10-new-members/580406-...biker-from-mn#580410

Thanks for the info.

I tried this method, but the bike did not react to the carb cleaner.

I did notice some other odd things.

As soon as I started the bike, when I took the choke off, the rpms raced, not dropped.

Once it was warm, by opening the choke, the idle would race then quickly drop and die.

After it was warm, the idle increased, without the choke on. Eventually the idle would drop on its own and then die.
Would be difficult to start at that point. Like its not getting enough fuel

This is definitely a warm bike issue.

I pulled the carbs again. Cleaned everything again. Bench sync'd them. Reset the floats.
Warmed it up, and again am getting the same issue.


Once it's warm, when you pull the throttle, the rpms rev up, but won't come back down. If they do, the bike dies.

Any other thoughts?

I'm missing out on some beautiful riding weather here, and we get very little

One other thought - you may want to ensure the timing advancer is lubed and working smoothly. If it is slow to react it can cause symptoms similar to what you describe. Ed

I'm assuming I should check the points & timing while I'm in there?

I've never done that before. Is it something a 1st timer can do with ease (I have a manual)

I don't have a timing light

Hello KZ people hope you are doing well? Today I just purchased my very first KZ1000P great old bike it ran great and it felt great but as I was riding it home it died on me. When I tried starting it up again it would not start then it finally started like 5 mins later and when it di it went into OD!!! scared the people standing around me and I must admit it scared me a bit to especially the bike only being 45 mins old to me I had to peck and search for the kill switch...haha very exciting.. I read the thread and I did notice that some of the cups are cracked I will replace all of those but if you guys have anymore suggestions I will really appreciate it. thanks for all your help and the great advice in advance!!