06 Ninja 250 - So many problems/won't start again

[jk3099]

TLDR: no idea where to go now. Bike won't idle without stalling out; carbs. already cleaned by Ducatiman, petcock replaced, oil changed (but might have flooded already). Where do I go from here?

Hi all,

Apologies in advance for the lengthy post; I'm just having lots of issues with my '06 Ninja 250. Last May, I bought this bike that wasn't running, thinking it wasn't in horrible condition; unfortunately, I think I was wrong. Every time I fix something, another issue seems like it arises, and I'm really not sure where to go since I think I broke my bike again (we'll get to that part).

Here's a timeline of what happened since then...
1. Cleaned carbs; tried it out, nothing
2. Changed spark plugs, coolant, and battery; bike ran
3. Occasionally, I noticed the bike would have issues stopping, idling, then its rpms would slowly creep down further and further until it died. After 1 week, the bike died completely in the middle of riding it.
4. Due to school and the winter, the bike sat for a few months. In the meantime, I sent the carbs to Ducatiman to clean them. I got them back and was ready to reinstall them come springtime (so I was pretty confident the carbs haven't been an issue). However...
5. I noticed a ton of rust in the gas tank. I thought this explained why my bike died after a week of riding. I thoroughly cleaned the tank with vinegar (letting it sit for 2 weeks and confirmed that a ton of gunk came out and that the tanks were now clean). I reinstalled the tank, the newly cleaned carbs, replaced the petcock's filters (which were torn), and installed 2 in-line fuel filters. It ran! However...
6. The petcock appeared to be a bit leaky. I wanted to test it out still, so I made sure the screws were tight and watched to see if it dripped. It still was dripping very, very slowly, but not enough to worry about at the moment. After taking the bike out on a test run, I had the same issues with idling. To be more descriptive, I set the idle at around 1500 to start off. The bike was fine with this for a few minutes, but after warming up, it dropped down to around 1000 or so. From there, it would start sputtering, and I would watch as the rpms crept lower and lower. If I turned the choke on or engaged the throttle, the rpms would spike up again, and it would go back to 1500 for a few seconds, but then slowly go back down. If I got moving, it really wasn't a problem, but whenever I stopped and was idling, the bike wanted to die. I tried upping the idle rpm value, but it wouldn't respond immediately. Only after turning the idle knob for a while did it suddenly spike up to 6000, which caused me to immediately lower it back to 1500 again, leading to the same issues. I also tried holding the idle rpms at values between 1500-2000, but no luck. The issues sounded nearly identical to the ones described in this thread: https://www.ninjette.org/forums/showthread.php?t=78505
7. Seeing as though the solution in that thread was the petcock and mine was leaking, repairing the petcock made sense and probably was the issue. At this point, I also noticed that the oil was incredibly dark/black, and it was way above the upper line. So, I decided I'd do a petcock repair and oil change concurrently.
8. Today, I did both repairs. Both went relatively well, though I did notice that the bolts from the oil change were definitely overtightened (to the point where the crash washer on the drain bolt was completely deformed/dented; an impact drill was probably used, that's how bad the washer looked). The threads still seemed like they were intact, so I just tightened them appropriately (14.5 ft/lbs) and refilled the oil. I checked the oil level on the center stand, off the center stand while upright, and after a few minutes of idling, and filled it so that it was underneath the top oil line. Jumped on the bike, and it seemed like it was having even more issues this time in neutral/idle, where it would try to stick to 1000 and then slowly die. I got it running by turning the choke on to start it up and opening the throttle. I was able to ride around a bit, but the exact same issue with the idle occurred when stopped (but not when moving). Knowing that it might be sitting for a while before I could get around to working on it (like a week to get parts), I decided to top off the tank.
9. Went to the gas station and noticed it died as I was pulling in. I filled my tank up, but afterward, the bike wouldn't start at all. I tried with the choke fully on, trying to throttle while starting it up, and twisting the idle knob; nothing at all. Eventually, the bike didn't even sound like it was turning over and was just making clicking noises. Out of curiosity, I checked my oil levels, and they were completely overfilled. I knew my bike wasn't going to start again, so I walked it home.

This leads to a bunch of questions... Did I flood my engine/carbs when I tried opening the throttle while starting the bike up? How did gas already get into the oil? People on the other thread suggested a valve adjustment, but I've been wanting to hold off on that because of how complex it seems, and I thought my petcock was the issue. If that's the next step, though, I guess I'm doing a valve adjustment. Additionally, I was thinking of taking the carbs off and seeing what happened there. Do I also need to change the oil again and look at my sparkplugs? Where else could the oil/gas have gotten? Where do you all think I should go? Again, sorry for the lengthy post, and thanks for anyone who's willing to listen/help.

[Triple Jim]

The combination of dying at idle and increased oil level makes me think that one or both float needles are sticking open, letting fuel get into the oil.

When it's trying to stall at idle, is there black smoke from the exhaust pipes? You may have to shine a flashlight though the exhaust gasses to tell, depending on ambient lighting.

[ducatiman]

agreed a carb revisit is called for, as well as a petcock redo/revue

AND a revue of tank to assure no more junk in there

AND get your valve adjustment DONE

total mileage on bike? Mileage when last valve service completed?

When did i do your carbs?

Examine your battery....charge at very least, replace if need be.

PM a'comin.

[jk3099]

Thanks for your replies, @Triple Jim and @ducatiman! I appreciate y'all's help

I didn't notice black smoke from the exhaust pipe, but I also wasn't observing it too close, and it was at night when it last fired up. I did smell a little bit of burning and thought I saw some smoking at first, so it's very possible.

In taking a look at the carbs, externally, they didn't look horrible. I trust Ducatiman's work, so my guess is there's probably something going on outside of the carbs (especially since this happened before and occurred immediately as I fired the bike up). We're working together to double-check the petcock and the carbs.

I looked at the tank, and it looked good. I have a clear fuel line and removed some gas from the tank, and there is minimal rust; there might be some flash rust, but I only saw one or two specks.

Seems like a valve adjustment is the next step. The bike's at 10,118 miles. I doubt it's had a valve adjustment seeing how the previous owners maintained it (ex: the tires are 10 years old, which is what I have to change once I get it running).

Will do on checking the battery.

Thoughts on checking the airbox? Could a dirty filter be causing this issue?

[jk3099]

Thanks for all y'all's help! I greatly appreciate it

I didn't notice any black smoke, but that's very possible since I was testing it at night and wasn't looking out for it. I did smell and thought I saw a little smoke for a second, though.

I'm pretty sure the carbs are good! @ducatiman's work was fantastic; the immediacy and reoccurrence of the issue make me think that it wasn't the carbs (maybe a setting issue?) or the gas tank (I double-checked that, too, and it looked good; maybe one or two specks of flash rust that were caught in the in-line filters) and is probably something else wrong with the bike. The petcock is very likely.

Will do on examining the battery! I'll charge it before I try starting it up again.

I'm probably going to have to do a valve adjustment. The bike's at about 10,100 miles. Considering how the last owners maintained the bike (the tires are 10 years old, which I'll have to change once I get it running), I highly doubt it's been done.

Could the air filter be an issue? That's the only thing I can think of to check other than the valves.

[Triple Jim]

For gasoline to get into the engine oil, the petcock has be be leaking, and the float valves also have to be leaking. Either one working correctly will stop fuel flow.

[jk3099]

That makes sense. When I go to change my oil again, do I also need to replace the oil filter? Sorry, very new to this.

[Triple Jim]

If the engine was started with fuel in the oil, then yes, since the filter got that mix in it.

[jk3099]

Sounds good. Thanks!