Odd motorcycle behavior

I recently bought an 04 kawasaki ninja with 8500 miles. I cleaned the carb and changed the plugs first things first and was told it had new gas in the tank. Today, after riding fine all day yesterday, I was on the highway going about 80 and the power slowly decreased till I had to pull onto the shoulder and died. The engine will start only if the throttle is turned and till rev up to 10k rpm but if you let go of the throttle completely, it does and it'll move on it own but not above 5 mph and 4k rpm. I'm suspecting bad gas but before I drain it all and get a tank of new gas, what do you all think? I filled up a few days ago but like I said, it rode fine all day yesterday with that gas in it. Thanks in advance!!!

 

8500 miles on an '04? It's been a garage queen. The carbs are likely fouled and need to be overhauled. Stored my dirtbike for 6 months in the desert without fuel stabilizer and the jets were plugged with a green corrosion. Fucking ethanol.

 

When you cleaned the carbs did you take all the jets out and clean them? Blow out the pilot circuit? Is there a fuel filter? Have you checked it?

 

sprayed carb cleaner through every port/jet and thoroughly cleaned the carb. I've put about 150 miles on it since the carb clean and this is the first issue I've had. Fuel is flowing through the petcock as fuel is in the line when disconnected from the petcock and an attempted start.

 

I did that too... wouldn't clean the ethanol corrosion out. I had to wire-probe out the passages I could, and I replaced all of the jets. The emulsion tube was trash.

But since you've put 150 on it without problems, I would suspect something else.
It could be the fuel (may have just gotten a tank of bad gas), but it could also be a coil pack or igniter going out.

 

what model is this?

 

Carbs need a deep clean since its been sitting for so long but also consider the fuel pump and filter. If the gas fouled then it would have gummed up in the lines/pump/filter. Maybe you threw a clot?

 

Start simple, change the fuel filter. My old bike did that to me once and it turned out to be a plugged fuel filter because there was some light rust in the tank. Water in the fuel could do that also and the way to get rid of that would be to drain the tank. I would drain the tank into a clear container, let it sit and see if it layers out, that would tell you if water got into the tank. When you drain it, make sure you drain the carb bowls also.