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View Full Version : ZX9R still not running right. Please help :(


Dunn-y
18-07-14, 05:42 PM
Basically I've had this rough idle and constant throttle surging problem since I bought the bike. So far I have...

Full service, including valve clearances, done by a dealer.
Cleaned carbs twice.
Attempted to sync carbs 5 or 6 times.
Tried various idle mixture settings, currently set at 2 turns out.
Checked for leaks but couldn't find any, but there could still be an air leak.

The video below shows what readings I'm getting on my carbtune when idling and at just off idle throttle which is how much throttle I need to cruise at 30mph. No amount of tweaking gets them to sync up perfectly as they are constantly changing but carbs 1 and 2 seem to have more of an effect on the idle than 3 and 4.

https://www.youtube.com/watch?v=MD7uC753bXI

Does anyone know of any possible causes for this? Next things I'm going to do is have the carbs sonically cleaned and if that doesn't help then get it on a dyno to see if that will help narrow it down.

Any suggestions very much appreciated. I'm completely lost on what to do next.

**The audio is terrible as it was recorded using my phone. Sorry

NTECUK
18-07-14, 07:19 PM
Can only say that the ultrasound cleaning is a good idea.
Found it was the only way to get a zzr 600 right that had been left for 2 years and two carb strip soaking in thinners had not removed the varnish deposits.

Dunn-y
18-07-14, 07:23 PM
Yeah that was my next step. I can't seem to get them to sync up at all. I've been quoted £100, does this seem a good price?

NTECUK
18-07-14, 10:27 PM
We called in a favour.

Bibio
18-07-14, 10:40 PM
if the carbtune is yours and you bought them new then i would suggest that you fit the dampers that come with them. you also have to read the instructions and this will tell you that if you hold the carbtune at a slight incline you will get a better reading.

Dunn-y
19-07-14, 10:15 AM
I have fitted the dampers and the carbtube was at a slight angle. I held it up myself after the video and numbers 1 and 2 still had more of an effect on the idle than 3 and 4.

Sometimes when I blip the throttle, on it's way back down it will dip under the normal idle speed then slowly increase. However it does this whether the mixture screws are 1.5 or 2.5 turns out, however it seems to happen less when at 2 turns out. Still confuses me as that would be a sign that it's rich, so I don't know why it happens more often when I lean the mixture.

I think a proper clean of the carbs is going to be my best option at the moment.