Motorycle Idle speed to high when engine warmed up?

Question

So I know the normal idle engine RPM would be somewhere close to 1,000-2,000 RPM.

So i start up my bike tonight. It took me a while to start up 'cause it is a very cold night.
After I started it up I used half chock to keep it running for a while.
then after about a min. I turn the chock off and let it run.
AT FIRST, the idle engine speed was 1,500 RPM. So it's totally fine.
BUT after the engine reaches normal temperature, my idle speed is 5,000RMP!!!!!!!
I didn't adjust anything yet, 'cause it was a really cold night.
Is there something wrong with my bike? (ninja 250)
If i adjust the RPM down, does that mean before the engine reaches normal temp. it will run at an extremely low RPM?

ALl inputs welcome.

Answer 1

For some reason your fuel started dumping into the carbs which is not normal.
It's possible that there was icing in the carbs like one answer said. That would act like a choke and cut off most of the air going into it.
Since you have a manual choke, I'll rule out an electric choke malfunction.
If you start playing with your idle, it will stall out on you. Your idle is not causing this problem. It sounds like it's adjusted fine.
Check to see if something is blocking your air intake. If you haven't run your bike in a while, it's possible a mouse crawled up in there or something and is blocking your intake which your engine will try and compensate with more fuel to stay running.
If the exhaust smelled extremely rich, I'd check for blockage in your intake.

If that's not the problem, you might need your carbs adjusted. Whatever the problem is, it sounds like your air fuel mixture is completely off.

Answer 2

The cooler air will make the bike run rich. It shouldn't have made your bike idle at 5k though. Mine idles at 2500 i have a Honda 500.... choke and throttle cable not sticking in their sleeves? I'd wait till a warm day, or after a long ride and see if the idle remains at 5k. .... icing on a bike carb.. I am not that die hard of a rider, so I couldn't rule that one out. More than likely, just the cold. Ride your 4 wheeler to work, its safer anyways in the cooler frosty weather, and much warmer as well.

Answer 3

This is quiet normal. The RPM picks up when the engine warms up. This is due to various reasons. But a 4000 RPM jump really doesn't happen. Check with your mechanic. If you try adjusting it, it'll definitely run at a low rpm.