KZ400b Carbs

Hi guys, I know this subject has been discussed a good few times, my newly rebuilt engine will not idle correctly, the revs will not drop below 1800 - 2000 rpm, unless I screw the throtlle down hard. I have put the vacuum gauges on and the left is drawing alot more than the right cylinder, carbs have been rebuilt, all old jets cleaned and reused, I have even swapped over the diaphrams just to see, all the same, had the genuine new boots off and sealed on, its sounds like drawing air, but cant find where from, any ideas.

Have you checked to insure that the throttle cables are properly adjusted and not hanging up?
Were the carbs bench synced before installing them? one carb pulling more vacuum than the other could be because they are badly out of synch.

Hi Texas,  yes I have tried to sync the carbs, which ever way i go, left or right the draw on the left pot stays the same, cables are genuine and correct, I have other bikes, all Kawasaki and dont have any problems with engines, just this one.

Have you checked that the butterfly plates are not bent?
I had this problem on my B2 and it was a bent plate. The plate could not close completely and it was as if the throttle was opened constantly, resulting in a hanging idle.

 

I whip the carbs off again and double check them, I will strip the beggars down again. 

The vacum is highest against a closed throttle so the side with the lower readings is where your problem lies (air leak/carb issue) have you checked valve clearances and compression (vacum is created my the mechanical " suck" from the piston down stroke)

Never ever seen a bend flaps/butterflys on carbs. Are you sure your carb sync adjuster screw or unit is installed correctly.
Some pics of the carbs/sync adjuster would help. Have seen a lot of mis-installed sync adjuster after a re-build.



 

I am going to remove the carbs today, will post up pics and what I did 

Wookie58 wrote:

The vacum is highest against a closed throttle so the side with the lower readings is where your problem lies (air leak/carb issue) have you checked valve clearances and compression (vacum is created my the mechanical " suck" from the piston down stroke)

Yes compression great on both sides, I agree issue is with right hand carb. Will double check valves before I remove the carbs. 
 

Right guys, checked out compressions again, all good, checked valves all good.

Removed carbs again..... Removed choke discs, emery around edges, lightly, refit screwed lightly, open and closed couple times to centre up, lock tight and screwed up tight, filled with oil to check tightness 
 

Refit carbs, checked cables. Started up and tweaked the balance 
 
success 

Compression and vaccum sync values are perfect, don´t forget to tight and secure the sync adjuster screw and nut with a drop of screw locking paint.