A difficult question?

[Lassesand]

My -84 XVZ12 is behaving strange. When cold the idling rpm is 1000. When warm it usually takes some second for it to drop from 2000-1500 down to 1000. If it's really cold ( 0 deg Celsius) the idling can get stuck at 2000 rpm and when not so cold (eg 7 deg Celcius) it can be 1500 rpm and in both cases does not drop unless you shut off the bike and start it again.

I sometimes get the impression that it runs on three cylinders but I'm not really shure it's ignition related or carb (or both). I did change all the carbs last year but that didn't cure the problem so I should say that it's more likely to be ignition related. I have had the Ignitech box installed all the time. I don't expect that you can give me a direct answer to this but someone perhas have some sort of idea what to look for? A check list perhaps.

 

Edited October 17, 2013 by Lassesand
added a link

[MiCarl]

Unfortunately there are a lot of things that can cause a hanging idle:

 

+ Poor compression on one (or more) cylinder

+ Idle circuit in one or more carburetors dirty or out of adjustment

+ Poor sync

+ Intake leak

[pmelah]

im no expert but i would say dirty out of adjustment carbs and poor sync i have that problem to but once it does warm up it gets better

[Yammer Dan]

All the above. My 85 did this after I pulled it out of that garage in Ohio. Took some serious Sea-Foam before it settled down. Done a Sea-Foam Soak??

[Marcarl]

I would say do a sync from scratch and then go from there. Let us know how you did or if you have more problems.