sticking throttle,,

I am not trying to hijack this thread just trying to understand and ask some question since i am having somewhat the same problem.

When you guys say put slack into the throttle cable what does that mean?? How do you put slack into the cables the adjusters at the carb side or on the throtlle itself??

WHen you guys say to adjust the air bleed screw is IN richer or leaner?

Post edited by: galaxian, at: 2007/07/25 22:49

Well I'm guessing you have Mikuni's that are as old as your bike. So turning the idle screw IN will be richer and out is leaner.

Just listen to the rpm's as you adjust it. Go which ever direction makes the motor run smooth.

At the end of the throttle cables are adjusters with lock nuts. Back off the lock nuts and adjust the upper lock nut up to make more play in the throttle cable.

It's hard to explain. Just turn it one way or the other and watch the braided cable get looser or tighter. (longer or shorter)

Hope that makes sense:S
Bob

You first install the cables up in your right hand switch gear. Note they have a barrel adjust and a locknut. Then you install the other end in the carb holder bracket with the tip installed in the bellcrank. SLACK means that the exposed cable between the bellcrank and cable holder bracket isn't tight. Slack means that there is some play in that area. This also means when you twist the throttle, there will be a very small first part of the twist where the cable isn't pulled... You can SEE the slack in the cable. It is just a bit loose. You put slack into the cable by adjusting the barrel adjust up on the switchgear so that you can SEE a little looseness in the cable. If the cable is taut, it WILL hold open the slides making idle adjust impossible.

As always you guys rock!! Thanks for clearing that up now i can adjust my cable properly.

As far as the idle goes are you talking about the one large adjuster on the carbs?? Because i am refering to the 4 screws (one in each carb). Is in leaner or richer and at what throttle position?? Meaning where will these screws make a dirrerence at 1/4 or 1/2 or 3/4 etc throttle position??

The large one in the middle adjusts the idle
for all the carbs. Lower is better.

You adjust the 4 screws on the carbs while the
engine is at as low of an idle that you can get
without stalling.

Bring the idle speed down a little.
Adjust the 4 idle bleed screws.
Bring the idle down some more.
Adjust the 4 idle bleed screws.

Keep doing that till you get a good reliable
idle as close to 700 to 800 rpm's as you can get.

Bob

The Kaw tach is mechanically driven but the mechanism that moves the needle is magnetic. It don't get more accurate with age. That is why it is important to set idle speed using your ear. Set it so that it is smooth... wish I could give a better description. It isn't really better to set it lowwwwwwww. If the idle is too low, remember that the oil pump is not spitting oil up towards your cam's plain bearings near as hard at 800 rpm as it is at 1200 rpm... That is why an idle speed spec IS listed for almost every bike and is listed at 1000 to 1200 rpm or so... actually, unless you have a shop tach, your ear is more accurate than the tach.

On the last Vulcan I had, which is a HIGH PRESSURE oiling system (unlike the KZ which is real LOW PRESSURE), the normal operating pressure was about 60-75 PSI but at idle, pressure went down to about 40 PSI. Lots of guys loved to try and make their Vulcan sound like a Harley and set the idle down way low for the potato-potato sound... The idle speed on the twin-carb Vulcan was about 1000 rpm and when I tried to idle mine down, I had an oil pressure gauge and noted it started to read 20 PSI when I got down to 800 rpm and would dip even lower if I dropped the idle speed... At normal idle, it didn't sound like a Harley but it did have some oil on the tappets!

I had a throttle sticking problem last summer. Turned out to be a cracked throttle and the cables were sometimes binding.

the throttle cables currently on the bike are the originals, never been changed. I bought some brand new Kawasaki cables to put on but the old ones move as freely as the new ones,, i cant justify changing them since i doubt there will be any difference.Currently the cables are as slack as i can make them, vey loose, and the bike throttle still sticks above 3000 rpm,,,:S

Well Mr. me109, you have got to set your idle speed lower. At the very least, just try it...It won't cost you anything to try it.

A low idle is NOT a bad thing. You only idle the motor for a minute or so every once in awhile. It gets plenty enough oil to handle it. If it was a problem they would have put in a high pressure oil pump.

You'd have to let it sit and idle for an hour to do any harm...And heat would be the biggest problem, not oil.

Good grief...do you want to fix it or not! Try some of the ideas all the good guys are giving you.

Good luck,
Bob

have played with the idle, and played with the cables,, i wont touch the air screws,, i am scepticle they have anything to do with it,,and we played through the whole scenario tonight with the same results,plain and simple, the throttle stix when its running, and dont stick when its not running.did it before the carbs were torn down and cleaned, still does it, no air leaks,, all new vaccuum lines, all new carb boots. out of options.

Well, if you can count to 2 or less its easy.

One carb at a time...turn the idle screw in till it
gently seats. Count how many turns it took to do that.
It should be something like 1 and 1/2 or 2.

Do that with each carb....

Now..you can try adjusting the idle screws without
fear of never getting it back where it was because
you have it all written down.

If you have problems....seat the idle screw, then
turn it out to where it was before...like 1 turn, or
1 and 1/2 turns, etc.

Its really that simple...and it makes a big difference
sometimes...actually most times.

Bob

me109g4 wrote:

have played with the idle, and played with the cables,, i wont touch the air screws,, i am scepticle they have anything to do with it,,and we played through the whole scenario tonight with the same results,plain and simple, the throttle stix when its running, and dont stick when its not running.did it before the carbs were torn down and cleaned, still does it, no air leaks,, all new vaccuum lines, all new carb boots. out of options.

The cables operate a bellcrank to turn a rod running through all four carbs. Each throttle slide is connected to the rod via its syncing mechanism.

Am wondering if something's loose in one or more of the connections so that the slide floats slightly off bottom until the ignition is turned off.

If not already done, possibly syncing the carbs might resolve the problem. And without syncing, could remove the top carb covers and inspect for any loose screws, sync nuts,etc.

With top covers removed, operate engine while looking in there to see what's happening with the slides during the progression of idle, sticking open, and turning off ignition. Might discover the problem. Will need an aux fuel supply with tank removed from bike (or use a temporary long fuel line from tank sitting on a nearby table or workbench).

Here'a diagram of the carb internals. Another diagram is in the following post showing the assembly.

Good Luck!