Very high and and black smoke after tune up

[Yountz]

Good morning,

I recently bought a 07 gz250, and I figured I'd give it a tune up. It wad running great before the tune up.

I took the carb off and cleaned it, removing everything including the jets which I sprayed out very well, and took a wire inside the tiny holes. I then reassembled it.

I took the gas tank off. I then took the petcock off the gas tank and cleaned it.

I adjusted the valves within clearance.

The choke cable was seized so I soaked it in oil and freed it up.

I changed the spark plug and did the oil.

I made sure the air filter was clean.

I reassembled everything seemingly correctly.

I didn't mess with any setting of the carb except idle speed.

When I started it up, I had the choke on instead of off, I had the direction confused.

Now it idles rough, and sometimes very high. It sounds like the engine is going to explode, so I shut it off. There is black smoke from the tail pipe which makes me think it's running rich. Keep in mind it didn't do any of this before the tune up.

It is rideable. Seems to do pretty well on the throttle. Does anyone have any ideas?