engine not running smoothly on idling

Good point, Bounty hunter. Does it run better with a little choke during startup?

During startup I have to fiddle with the choke all the time to make it run. No choke, it dies. To much choke, it rves way to high, up to 5-6 k. When lowering it, I still have to fiddle with it, so it doesn't die or rev up.

Still, during startip it sneezes even when using the choke, so answering you question would be NO I suppose. Not until it gets warm I can turn off the choke.

I wonder if one irregular cylinder can cause this much difference in temperature. ONe was also a bit wet (and warm) but theother was dry (and cold). Its the left exhaust that is colder and I have always thouught that it is number two that runs a bit lean. When turning in the air screws completely on these two, almost nothing happens. If I do the same on the other two carbs, the engine eventually dies.

M

Marp68 wrote:

Good point, Bounty hunter. Does it run better with a little choke during startup?

M

Mine dies without choke cold. After a couple of minutes, I flip it off.


Marp68 wrote:

During startup I have to fiddle with the choke all the time to make it run. No choke, it dies. To much choke, it rves way to high, up to 5-6 k. When lowering it, I still have to fiddle with it, so it doesn't die or rev up.

same here


Marp68 wrote:

I wonder if one irregular cylinder can cause this much difference in temperature. ONe was also a bit wet (and warm) but theother was dry (and cold). Its the left exhaust that is colder and I have always thouught that it is number two that runs a bit lean. When turning in the air screws completely on these two, almost nothing happens. If I do the same on the other two carbs, the engine eventually dies.

Then they aren't doing much at idle. Sync problem or pilot problem.

Hmmm, maybe a stupid question, but what exactly do you mean by "Then they aren't doing much at idle"?


Is it difficult to sync the carbs? Does it include special and/or expensive equipment? If so, can it be done in an easier way, as a pre-testing?

I also just checked the cost for a compression test equipment, and it wasn't that expensive at all. The cheapest costs 22 dollar. I think I will buy one and make the test myself. Can this test also tell me if the valve settings are okej? Or do I have to measure it by hand?



M

Compression test will tell you which cylinder is bad.
For valve clearances you have to open the head to check clearances and if there is a problem and you fix it you will see that compression test numbers will improve after doing so.

-misfire during startup (sneezing), then just a bit irregular idling

The popping you hear is from a lean start up mixture. This is because you take the bike off choke to early. This is very normal until the bike warms up and you are off choke.


-different smoke temperature, lukewarm and cold (after startup during idling)

Several folks have suggested you check compression. Not only check compression but valve clearances and timing... heck tune the bike up and part of that is to sync the carbs. Sounds like the bike has never been tuned since you have owned it so exhaust temperature questions are more or less a waste of time since the state of tune of the bike is questionable.

-bogs down when turning the throttle to fast during idling and on the road

No jetting or pilot mixture screw settings have been noted. Sounds like the pilot mixture is not quite right as that is what affects the off-idle transition to mid-range.

-sooty dry plugs

Normal for a bike this age... can be a zillion things. Dirty air filter(s), inappropriate jetting or carb adjustment, lack of valve clearances, timing off, low voltage at spark plugs, wrong spark plug type, a weak component in the ignition system... etc etc. Tune the bike up. Part of a tune up is new plugs. Once you have tuned the bike up and had a chance to ride it some, look at the plugs again and see if they are still sooty.

You're absolutely right, wiredgeorge. It hasn't been tuned by me. Just bought it last autumn and have just rode it a couple of times since then. Since it runs rather well I want to ride it now, and don't take tha engeine or carbs apart and risk that something goes wrong i the beginningof the season.

So I intend to buy the compression test equiment and test it this weekend. If I don't have to take the carbs apart, I also would like to sync them. And also check the the timing?

How do I sync the carbs? Any need of expensive or special equipment?

How do I check the timing on the electronic ignition system (previosuly changed by owner)? Any need of expensive or special equipment?

At the moment my financie are really bad, so I want to do as much as I can by my self. I also only have a repair book fro kz 650 to -76, so some things doesn't apply to my model. Anyone know if the manual for the later models can be found on the net? Or information regarindg sync and timing?

Have mercy on a beginner to these lovely old bikes...

M

Marp68 wrote:

Hmmm, maybe a stupid question, but what exactly do you mean by "Then they aren't doing much at idle"?

If you can crank the idle mixture screws around sith no effect, they aren't adding much to the mix. If they are not synced, it's possible that at idle one of the throttle butterflies is closed and that cylinder isn't getting enough gas to run. So, if you crank on the idle screw, you don't see any change.

Marp68 wrote:

Hmmm, maybe a stupid question, but what exactly do you mean by "Then they aren't doing much at idle"?


Is it difficult to sync the carbs? Does it include special and/or expensive equipment? If so, can it be done in an easier way, as a pre-testing?

I take the carbs off and do it by eye, the factory manual says that's good enough. After you take them off: Adjust the idle speed set screw to open the butterflies a bit and look into the throat (engine side) and see if they are all open the same amount. If not, adjust until they are equal. There should be some way in the linkage or shaft clamps to change the mechanical position of each to sync them. It's easiest to see small differences if the butterfly (throttle plate) is almost closed.

Hi

I thought I had better start a new thread on this matter that drives me crazy.. I have already got som good thoughts from you, but now I have to revise the problem indications. The problems are not big, but enough to irritate me.

Hey does the engine sneeze through the carbs if so my engine used to and come to find out one of my valves need to be shimed could believe at first but sure enough reason im saying this is because i have a kawasaki j model and it started doing this

Hello, A compression test would tell you a great deal. My bike was idling roughly and running fine on throttle. Sometimes it would pop through the carbs. And you could definitely feel the diffrence in temperature of one of the exhaust pipes (I touch the pipes when newly started with a cold engine, you could feel exhaust pipes quickly heating up,the bad cylinder would just be warm ,you wont get burnt when you touch it even when warmed up, BE CAREFUL WHEN YOU DO THIS PLS., the temperature of the good cylinders would burn you even after only a short while fron start up). It turned out one cylinder had a very low compression because of blow-by through the rings.

Hello, A compression test would tell you a great deal. My bike was idling roughly and running fine on throttle. Sometimes it would pop through the carbs. Even though it had new plugs and carbs synchronized. You could definitely feel the diffrence in temperature of one of the exhaust pipes (I touch the pipes when newly started with a cold engine, you could feel exhaust pipes quickly heating up,the bad cylinder would just be warm ,you wont get burnt when you touch it even when warmed up, BE CAREFUL WHEN YOU DO THIS PLS., the temperature of the good cylinders would burn you even after only a short while from start up). It turned out one cylinder had a very low compression because of blow-by through the rings.

bountyhunter wrote:

Marp68 wrote:

Hmmm, maybe a stupid question, but what exactly do you mean by "Then they aren't doing much at idle"?


Is it difficult to sync the carbs? Does it include special and/or expensive equipment? If so, can it be done in an easier way, as a pre-testing?

I take the carbs off and do it by eye, the factory manual says that's good enough. After you take them off: Adjust the idle speed set screw to open the butterflies a bit and look into the throat (engine side) and see if they are all open the same amount. If not, adjust until they are equal. There should be some way in the linkage or shaft clamps to change the mechanical position of each to sync them. It's easiest to see small differences if the butterfly (throttle plate) is almost closed.

Thats the "bench-sync" part of it. To get it right you should sync carbs with a running engine. Doing it by-eye gives you a rough synching. Check this site: www.carbtune.com/ It´s one of the best tools for this job and on the menu left there´s a good "Operation" advice how to do it. And it´s not difficult and it´s not too expensive either. Around 90€ = 800-900SEK.