I've got a'94 road king that runs great with the exception of the idle, well it's kinda like it has two idles. Upon starting it has a super low idle, it will actually die if I let it go on for a minute or so. However after I've been riding it for a while and stop at a light it will sometimes idle like normal but only for a few seconds, then it goes back to the super low idle. It is less prone to dying after warmed up but when I gas it from the light it coughs. any ideas about where to start troubleshooting? Carb was rebuilt about two years ago but I don't think the shop addressed this problem

 

What kind of carb do you have?

 

Stock cv, it's all stock aside a Kuryakyn hyper charger that has been on it for the majority of its life. I do not know if there has been any rejetting but I noticed the soft metal plug that comes from the factory over the mixture screw has been removed.

I'm "borrowing" the bike from my dad who bought a 2009 RK a few months ago. He has the service records and kept great care of it but the records are not specific.

I have adjusted the idle a couple times which does make a difference when it is idling like where it's supposed to but has no effect on the super low idle

 

I have noticed that when it is really warmed up, operating for about 15 minutes of good riding, the idle has a tendency to stay where it should. I tried this on my way to work today and sat for about 6 minutes idling once I got to work and it did not drop. However, I shut it off, let it sit for about 5 minutes and restarted it and the idle was dropping again.

 

I wish I knew more about CV carbs to help you.
Best I can guess is check the rubber diaphragm on the top of the carb under the black cover.

 

How many RPMs do you have it set at for normal, fully warm idle? Needs to be right around 1000.

 

I don't have a tach installed, so I really have no idea what RPM the idle is or what RPM the super low idle is. I dont see how it could matter much however because I have adjusted the idle screw and no matter where its set it seems to hold only after being sufficiently warmed up. When the idle does drop it goes all the way down to just barely breathing so to speak, regardless of where the normal idle has been set.

 

I plan to do a little tuning, as suggested by the CV performance.com website, don't know when exactly I will have the time but I hope that will end with more answers than questions.

Am I safe in pursuing this as a carb issue at this point?

 

It sounds like what you have might very well be 'normal'. There is a 'star wheel' on the throttle control (or should be). When you first start up, turn the throttle to where the engine sounds about right (around 1K RPM) and then turn the star to lock the throttle in that position. Once the bike warms up, turn the star the other way so the throttle spins free again.

Use the Enrichener on startup if it's real cold. You'll have to judge at what temp it's required. I'm guessing 60* or warmer you can just give the bike a couple of 'squirts', using the throttle, and it should start.

When the bike is good and warmed-up, adjust the idle-screw (on the carb throttle cam) so it idles at the right speed, e.g. around 1K RPM give or take 50 RPM or so.

If this doesn't resolve your idle issue, there could be other issues with mixture, etc.. But try this as your starting point. A carburetor is not as precise with regard to 'idle' as a fuel injected bike. Even when ****-on, a carb'd bike can vary a couple of hundred RPMs (maybe more) from 'cold' to 'hot' with regards to idle-speed with 'you' being the "ECM" required to control it.

Alan

 

I'll do that, thank you Alan