bike will not start

I got my 1977, KZ 650 back together. It started a couple times, but would only run if I kept the RPMs up over 2000. Went out this morning to check the throttle cables etc, now it will not start at all. I am getting fuel to the float bowls but not sure from there. There is no gas in the air so I assume it is not flooding. I did notice that the clutch is not operating smoothly. Could that be part of the problem? I also noticed the thumb screw for the idle is almost all the way out, could that be a problem? Any and all help will be appreciated. Thanx for your time and efforts ... PEACE Larry

The idle screw should not be backed out. It sounds like a carb problem, but just to be sure, I would:

1) check compression

2) check static timing

3) check spark plugs against the cylinder to observe good spark

4) check plugs to see if they are wet (getting gas)


This part:

would only run if I kept the RPMs up over 2000

definitely sounds carb related like a vacuum leak or a plugged jet.

thanx bountyhunter

May wanna check the timming advancer weights,make sure there not stuck.Pretty common problem.
Good Luck

Did you pull in the clutch? The 77 650 has a clutch lockout switch that will not let it start unless the cluch is pulled. Unless you are kicking it then it does not matter

Would also check valve clearances, because insufficient gap may cause onset of compression loss at normal operating temperature.

Failure to idle down may also result from imperfect carb pilot circuits. If turning pilot adjustment screws doesn't produce rpm change, there's likely something wrong in the pilot circuit (typically inadequate cleaning), especially where ignition (spark and timing and advancer function) and compression (including valve clearances) are okay.

Good Fortune!

Kawickrice wrote:

Did you pull in the clutch? The 77 650 has a clutch lockout switch that will not let it start unless the cluch is pulled. Unless you are kicking it then it does not matter

The 92 1k is that way as well.

but as mentioned, generally it is a carb adjustment issue. Then, the also mentioned mechanical checks. good luck and enjoy the training.

I think you folks were right about the clutch. That was the first thing I did this afternoon. Then it started pretty easily, but the RPMs still go up and down a little and it idles a little rough. I did notice it kept idling with the petcock in all three positions. Thats right including the "off" position. Should the throttle cables be come taught when turned in or out respectively? PEACE Larry

Thank you all so much!!!!!

As far as idling w/petcock off, even after turning the petcock off, there is still fuel in the system (float bowls, fuel lines), enough to keep it running for a little while, especially if it is just idling.

Generally, there is just enough fuel left in the lines to get you halfway through an intersection when you forget to turn it on after filling up :laugh: