Idle is unstable, bike dies if idle speed under 2200rpm

[carloxic]

Hi,

This bike has had 2 previous owners who have taken very good care of it (at least aesthetically).

Im not sure when they did maintenance on it. But I'm guessing at least 1 oil change was performed, maybe 2. The bike has 5000km - 3125 miles - and is 10yrs old.

So when I start it up to go to work in the morning, even with the choke on it's impossible to leave it there without opening the throttle - it will die.
I have to prevent it from dying on me with the throttle...
If I use the idle speed to "fix" this lazy start the bike will be revving high on neutral later on when it's warmed up - of course this is not the right thing to fix anyway.

At first I thought this could be a leak, air intake or sth... but then the problem would not disappear once the bike warmed up, right?

So it has to be something else?
My guess now is that the oil is too old or spent and if I change the oil I should be good...

So my question is if this makes sense or should I be watching out for other issues?

[CavemanBen]

Yor manual says to change the oil every 7500miles, but it never hurts to do early (especially if its posably ten years old). But the oil is not your problem.

Vacuume leaks tend to cause the opposite reaction (idles fine, stalls on throttle)

So id blame a partially clogged idle jet. I.e., clean your carbs.

Less likly but possable is old gas, how long has the bike sat?

[carloxic]

thanks for the quick reply! it's quite early in the morning in the US right?

I was affraid I'd have to clean the carbs... have ZERO experience in doing that and I need the bike running, can't afford to mess this up.
Watched tens of videos on how to do this, hope I'm capable...

The gas is new, I filled the tank twice already.

One question remains tho, if the problem is in the jets why does the idle turn OK once the bike is warmed up?
shouldn't the prob be present regardless?

I figure cleaning the carb is a good thing to do anyway since it's an old bike.

[CavemanBen]

Gas likes to stick to cold cylinder walls rather then vaporizing and ignighting, thus the choke. So I'm thinking that the pilot is dirty, not intirely clogged, so until the cylinders heat up you need to force in some extra gas to compensate. As far as cleaning carbs goes, watch a bunch of youtube vids, that's how I learned. Be carefull not to get any carb cleaner on the CV boots! Just pay attention and take lots of pictures.
And one more thing.... carbs are a B%$#* to get 100% clean, it very likely will take more then one attempt

[carloxic]

Thanks for the support CavemanBen.
The only thing that demotivates me is that (by the looks this thing is sitting there) I will need to remove a sh*tload of stuff before I can get to the carbs. Since I'm new to this it'll take me a whole weekend at the least...
Just changed the oil and the filter on her saturday and it did look like it was needed. I tried to make a video but was not very successful at doing sth with one hand and filming with the other.

[carloxic]

OK.
2 weeks ago I changed the oil, as i wrote on my last post. No improvement.

This weekend I worked on the carburetor, removed it, cleaned it. No improvement.
The carb was not gunked up anyway, just had minor signs of fuel residue.

I still need to control the throttle to prevent it stalling when warming up.
Idle speed has been set higher so as to have the bike start up and warm up without my assistance, *BUT* after driving 5~10mins the idle becomes just waaaay to high and I have to reset it.

If I start the cold bike with choke it will initially rev higher (not surprised) but then will stall even quicker than without choke.

W-T-F.

After reading around all this time I suppose this is just how the bike is. I will tinker for a while longer and perhaps play a little with the air/fuel idle mixture screw but honestly don't have big hopes to solve the issue.

[carloxic]

I'm also suspecting something could be wrong in the exhaust system... valves, tubing,,, i dunno.

What makes me think this? Well once I started her up a little angry and went full throttle on her, she staggered and stuttered considerably like she was choking (choke was not active btw) until finally she reached a higher rev that corresponded to my throttling.

Makes me think there is something that gets stuck after I turn her off and overnight it becomes lodged on the cyl walls or sth... maybe it's humidity?

[carloxic]

Fixed.

I opened a new thread with some guidance for others who might need to do this too: Idle or slow air-fuel mixture adjustment