NEWBIE QUESTION ABOUT IGNITION

Ive just recently bought my first kz. i got a 82 kz 750. the only issue i have with the bike is that it stumbles a little off the start but it clears up perfect after about 3000-3200 rpms. i was wondering what all i could replace on the ignition set up to make sure i had a good tune up. i already put new plugs(factory) and some good 100 octane gas also. again, it runs perfect after 32000rpms. here's a pic. its stretched and lowered. thanks in advance guys. love the site.

Welcome aboard. Nice bike. It sounds more like carbs than ignition. I would start by making sure the carbs are squeeky clean inside before I made other changes. Also, I see the bike has a pipe. It's possbile that the P.O. monkeyed with the jets but didn't get it right trying to tune for the pipe. Ed

waterwalker wrote:

Ive just recently bought my first kz. i got a 82 kz 750. the only issue i have with the bike is that it stumbles a little off the start but it clears up perfect after about 3000-3200 rpms. i was wondering what all i could replace on the ignition set up to make sure i had a good tune up. i already put new plugs(factory) and some good 100 octane gas also. again, it runs perfect after 32000rpms....

Hello, Jeff, and WELCOME to KZR!
We're glad you're here!

I concur with 650ed that carbs are a likely suspect. And thinking pilot circuits may need cleaning, and possibly different pilot jets. Or maybe just needs some low rpm tuning with the pilot adjuster screws.

Also wondering if original ignition with igniter is still being used, or if it has perhaps been replaced with a Dyna-S or other ignition.

But before further addressing the carbs, if not already done, would remove plugs and observe spark quality while spinning the engine over. Look for fat blue spark.

While the plugs are out, could also do a compression test, and assure that valve clearances are within specs.

Would also use a strobe type timing light to observe the advancer unit moving back and forth as rpm is varied by blipping the throttle. This being to assure the advancer isn't hanging in the forward position, and is immediately returning to full retarded position (F mark aligned) when the throttle is closed. A sticking advancer may impair lower rpm performance.

Imo it's good to first rule out any non-carb issues.

Good Luck!

where is the ignition igniter located? also, is it going to be a terrible job removing the 4 carbs and putting them back on? i dont mind doing the wrench work, ive rebuilt several car carbs and dont mind working on cars, but bikes are new to me. any info would help. but first im going out to check the spark. also, where are the pilot adjuster screws? thanks guys

it won't be your ignition what you have described is a carb issue first things first get a proper manual the ignition plate is located under the small round cover on the right side of the motor and it can be a royal pain to remove the carbs if the air box boots are hard and dried out. so get your self a manual and go through all the steps pertaining to what your about to do first before you turn a wrench. when you get that accomplished then we can help yopu thru the rest . by the way the pilot screws affect the bottom end not the mid-range where your problem is.

waterwalker wrote:

Ive just recently bought my first kz. i got a 82 kz 750. the only issue i have with the bike is that it stumbles a little off the start but it clears up perfect after about 3000-3200 rpms.

I definitely vote for pilot problems, just went through this on my 750 twin. If the carbs are clean and no vacuum leaks or any other problems:

My guess:

1) set gas (float) levels in bowls

2) rich up pilots (maybe need bigger jets)

3) rich up needle settings

I would also check the timing advancer and see if the advance follows the factory curve (see manual). If not,that will really screw up low end acceleration.

my problem is at the bottom end. the bike stumbles until about 3000rpms then it clears up. can the "pilot screw or screws" be adjusted on while the carbs are still on the bike? if so, where are they? i will be trying to locate a good manual in the meantime. thanks

waterwalker wrote:

my problem is at the bottom end. the bike stumbles until about 3000rpms then it clears up. can the "pilot screw or screws" be adjusted on while the carbs are still on the bike? if so, where are they? i will be trying to locate a good manual in the meantime. thanks

I think yours is a four? I haven't done those, but you can go to babbittsonline.com (OEM section) and enter your model and year and get the explosion drawings for your carbs and it should show the parts.

Pilot adjust screw is 16014:

The 100 octane will be hard to light off with a stock compression motor/ignition, I would stay with the 87-89 octane and see if that helps

muddy1

it was doing it before the 100 octane. this bike had been sitting 3 months when i got it, so i thought it might be good to run some good gas in it. when i run this tank out, ill go back to 87. thanks

sounds like your probblem may be a clogged pilot circuit. what do your plugs look like when held at 2K or so. if white its running lean.

or your ignition advance could be stuck in the advanced spot. i dont know if it is common or not. but seems possiable. i believe that around 3K is where it changes....

No eBay APP ID and/or Cert ID defined in Kunena configurationWould suggest getting the official Kawasaki Service Manual, although an aftermarket version can also be helpful.

Manuals frequently appear on ebay.



Could also try running some SeaFoam (or similar carb cleaning product) in with a tank of fuel.

Good Luck!