KZ440 - Runaway with Choke OFF

Hi guys!

I have finally figured out my starter issue but ran into new problems.
The bike starts really well with choke on, idles at around 2-3000 rpm, once I remove the choke the idle speeds suddenly jumps to 7000-8000 rpm and I have to shut it off.
Things I have done so far:
- Overhauled the carb with new gaskets and jets
- Synchronized the carb with the wire-method
- Checked the choke valves for synchronicity
- Adjusted the float level to 22mm 
- Checked the gaskets for any cracks/holes
- Replaced the intake manifolds 
- New Plugs
- Checked with Starter Fluid for any leaks around carb and motor
- Adjusted the timing
- Checked valve clearance
- Checked if there is a difference with air filter and without air filter

I am really running out of ideas what to check next. Do you have any ideas?


Lukas
 

When the throttle is closed, is there plenty of play in the throttle cables? Are you at the limit of the idle speed screw? With the throttle closed, can you push on the linkage to get the throttle plates to close more? Remove the throttle cables from the carbs and operate the throttle by hand.

Is the throttle cable and idle adjustment adjusted correctly to allow the throttle to close fully when released

Edit: looks like ckahleer is on the same page, didn't see his post before I uploaded 

Yes! I have checked that the valves are closed once I installed the throttle cable. Then I turned the idle screw 2-3 turns in, this just keeps the bike barely running with the choke on.
Once I then turn the choke off without touching the throttle at all the bike runs away.
I also can push the linkage to close the throttle even more, means I think I have enough play.

I sprayed the whole carb with starter fluid and did not notice increased rpm.

 

To rev that high it must be getting air from somewhere ???

Exactly what I was thinking. There has to be some vacuum leak but I almost covered the whole bike with starter fluid.
I sprayed the valve covers, cylinder head gasket, intake manifolds etc. 

The only thing which still bothers me are the plastic plugs in the carb ( the ones with the o-ring which seal the pilot jet). I did not replace them, since they seemed ok, just used some silicone spray when I reinstalled them.

 

Sounds like the throttle butterflies are too far open.  The choke mechanism has its own idle speed control mechanism, so try backing off the throttle stop until you get a reasonable idle.  Of course, this assumes no air leaks.  Also, if you are running pods, the bike will never carburate correctly until you do a full rejetting.  And make sure the pods are not junky china crap.  Get real deal K&N, UNI, or something similar.

I am not running any pods. I am running the stock air filter.
 

Lukeduke wrote:

Once I then turn the choke off without touching the throttle at all the bike runs away.
I also can push the linkage to close the throttle even more, means I think I have enough play.
 

I think that means the opposite of what you think it means.

If you can release the grip and then push the throttle shut even more, then something is not letting the throttle fully close on its own. This could be caused by binding in the cable (due to incorrect routing) or the cable is dragging in the sheath (due to insufficient lubrication).

Lukeduke wrote:

Yes! I have checked that the valves are closed once I installed the throttle cable. Then I turned the idle screw 2-3 turns in, this just keeps the bike barely running with the choke on.
Once I then turn the choke off without touching the throttle at all the bike runs away.


 

The high idle cam slightly opens the throttle plates when choke is applied. If you are turning the idle screw in to keep the bike running when choked, the throttle plates will be way to far opened with choke off.
Get the bike running as you have. When you turn the choke off, be prepared to quickly back off on the idle speed screw.
Once properly set, the throttle idle stop tab should come off the idle speed screw as choke is applied.
Note: keep plenty of play in the throttle cables. They will tighten up as the you back off the idle speed screw.
 

Thanks a lot guys! The issue was really the wrong method plus too much tension in the cable.

Bike runs now very well and idles perfectly. Great progress to get the bike ready for riding.

Luke