Diagnose this............

[ctandc]

Just curious.

Bike is a pre 98 Kat 600.

- Stock air filter / airbox
- Stock carbs no jet kit
- Good plugs

Symptom: Bike is very cold natured. Will start right up with 3/4 - full choke. After 30 seconds or so, idle will climb. Reduce choke to keep bike running around 2K. After about 2 minutes or so, if you turn off choke, you can hop on and ride, but for the first few minutes, at a stop, bike idles very low, and usually needs assistance to keep running. After that bike idles fine. Not 'rock solid' but pretty steady...around 1300-1500 RPM.

Bike runs VERY WELL beside the idle issue. No flat spots etc,

Pilot screws are at 2.25 turns out. Stock jetting.

Adding an ignition advancer seemed to help the bike get warmer quicker, but idle issue has stayed pretty much the same.

What could cause this?

Ready.......begin.......

[The CyberPoet]

Mostly temperature.
The fuel coming out of the carbs is cold, the bike is cold. As the bike heats up, the fuel vaporizes better on it's way into the cylinder, resulting in more power and better combustion. Add in more drag from the cold oil still warming up (and the pump having to push harder to move it), and it all makes sense. Plus running the choke that long could be partially fouling the plugs.

TRY THIS:
Instead of running it for two minutes, in truly cold weather, let it warm up for four or five (most of that time with the choke OFF). If the fins on the side of the engine aren't at least as warm as your hands, it's still too cold.

Cheers,
=-= The CyberPoet

[GytRDunKat]

Start it, put gear on, then worry about it

[Cheriff]

If it is running normal by the time you get a mile or two down the road I think it just needs a little more time to warm up. Certainly no expert on the subject, I think it is normal behavior of a carb operated machine.

[ctandc]

I know alot of it has to do with being an oil cooled engine. And I have plenty of carb experiences with other vehicles...

But compared to my old GS500E (oil cooled) it just seems cold natured.

[The CyberPoet]

But compared to my old GS500E (oil cooled) it just seems cold natured.

A large part of that is the amount of oil in the bike -- the GS500E took something like 2.6 liters (2.8 quarts), while the Kat holds almost double that.

Cheers,
=-= The CyberPoet

[hardlydangerous]

It's complately normal for this time of year. You could adjust the mixture screws for the cooler weather but I agree with CP just let it warm up longer. A nice slow warm up is a lot easier on the engine then rushing it.

[reconstyle]

That's normal dude, you don't have anything to worry about.

[md86]

Yeah , it's fine . Nothing to diagnose . But just in case , how are them plugs ?