[Bando909]

So hello everyone,

Recently I acquired a 2004 Ninja 250, Bought it one the north side of the city for $400 non running. So I went ahead and did some things since the bike had 16,000 miles and probably no maintenance was ever done to the bike.

However I do have one issue that is baffling to me,

The bike will start cold no problem, however once it just gets above the second white temperature line and enters into the big space on the temperature gauge the bike just drops idle and stalls out. Having a really hard time with this and the strange thing was the bike ran beautifully yesterday.

So here's what I did so far.

- New Engine Oil and filter, cleaned oil screen as there was some decent debris in it Oil level is just below the upper tick mark when bike is level and both tires on the ground. The previous owner filled way too much oil into the bike and it was pushing it into the airbox. So once I changed it the problem has since stopped.
- New Coolant, Flushed with distilled water then added Engine Ice
- New Spark Plugs
- Tightened chain and oiled it as it was very loose
- Tire Pressure and tread ok
- Just cleaned carburetors and installed a brand new rebuild kit as it was very dirty. So new Pilot Jet, Main Jet, Air fuel mixture screws, Needles, float bowl gaskets, and new screws for the diaphragm and float bowls. I also checked the rubber in the diaphragms and their are no rips or tears, Float Heights are at 17mm so in spec. Air fuel screws are at 2 3/4 turns out and the bike was very happy zooming along yesterday.
- Benched Synced Carburetors
- New OEM airbox boots, both were very hard and one was deformed so I replaced it. I did split the airbox however so I'm not sure if that gasket would cause a problem.
- New Air filter
- Valve clearance check, I set the Intake valves to .005 and Exhaust to .006 Inches. All checked out when I just was in there. However when I first did it All the valves were extremely tight so make me believe no service was ever done to them.
- Inline fuel filter as the gas tank was nasty inside, Probably at least a year old gas so I rinsed it out as best I could and put new gas and a fuel filter in.
- Checked ignition coils for spark by grounding the spark plugs to the frame of the bike and both have good spark.
- Cleaned Cam Chain tensioner, Used brake cleaner and synthetic grease on the ball bearings, heard the click when I unloosened the screw then re-tightened it.
- Checked timing. Both the EX and IN lines on T2 lined up on the head of the engine 33 chain rivets in between which checked out and I believe is ok.
-New Battery

I'm at a loss right now and I cant seem to pin point the problem. I would like to think at this point its a vacuum leak somewhere or that the valves are messed up possibly from not being adjusted ever. I have the intake boots for the carburetors on the way to replace those with new clamps next to see if that could be the issue but I would like to know if anyone would have a suggestion on what else to check next.

However when I did clean and reinstalled the cam chain tensioner the bike wasn't wanting to turn over almost like something was holding the starter motor back from spinning. Also made a bang sound, Eventually it did stop so I just thought the chain tensioner wasn't seated right and that eventually it snapped into position and the bike did ride after that happened. So I don't think anything of it but it's just a thought. I also checked the valves and timing after that and it was spot on still.

Thank you

Tyler