I took my 2006 Ninja 250 first time on the Angela's national forest, it was about 5 miles of twisty roads. I have no problem going up 80% of the way, but since this is a 250, I had to give it a lot of gas to claim up the mountain, after driving roughly 80% towards the destination, then suddenly I feel like I am slowly losing power and throttle is less and less responsive.

So I ignore it and drove to where I want to go, took 10 minute break, and decide to ride down.

Suddenly I feel the bike is slowing down, and when I give it gas, I would feel like is engine is chucking along in bursts, I would be jerk slightly forward every 1 second or so, aka engine is giving power, no power, power, no power... Until the throttle just complete stop responding, so I pull off to the right, as soon as I stopped the bike the engine would shut off.

I put it in neutral, start the engine, it starts, put it in 1st gear while holding clutch, but as soon as the clutch is opened up a little bit (1 inch) the engine stops, the clutch is FAR away from the friction zone and the engine stops.

So, I start the engine again, this time I tried to roll the bike down hill while holding the clutch, once I gain some speed (5mph) I open the clutch and it was no problem, but 2 minutes later, bike start to loosing power again, and again I have to pull over to the right, this time the engine won't even start.

I was worried I was going to be stranded on the mountain, but at this point, I was already 80% down. So instead I tried something else, I put the petcock from On to Reserve, I was able to start the bike and afraid of loosing power again, I put the choke on half way, I drove the bike all the way down with no problem, turned the choke off and was able to drive the rest of 10 miles home without any incident.

So what do you guys think is the cause of the problem? I don't think the fuel tank is empty, after home I open up the tank and I think it is half full, is there something wrong with my petcock? Or was I actually low on fuel with "On" switch of petcock? Or does it have to do with riding up the mountain using too much engine?

Fill up your fuel tank.

...........So what do you guys think is the cause of the problem? I don't think the fuel tank is empty, after home I open up the tank and I think it is half full, is there something wrong with my petcock? Or was I actually low on fuel with "On" switch of petcock? Or does it have to do with riding up the mountain using too much engine?

If the tank is still half full after returning home:

How far can I go after putting the fuel petcock on "reserve" (http://faq.ninja250.org/wiki/How_far_can_I_go_after_putting_the_fuel_petcock_on_%22reserve%22)

After 7 years of storage that internal mesh filter in the tank for the on position may have some restriction in a way that it allows proper flow of fuel with a full tank but not when the level is lower.
Going downhill may exacerbate the problem.

I'm thinking it wasn't the tubes being mixed up.

Try disconnecting the clear tube that comes from between the two carbs and goes to a canister thing. Disconnect at the cannister. See if that makes any difference.

Did you test your petcock per the instructions in my blog below?

On the way back down it was probably just out of gas. The fuel pickup is at the rear of the tank and going downhill would have run the gas toward the front of the tank.

Ok thanks guys, just wanted to make sure what I described are the characteristic of low on gas, not anything serious.

n4mwd, I didn't do the full test, I did disconnect the big and small tube connected to petcock, and no gas is flowing out, I need to find another tube to connect to the small tube to suck on it to see if gas come out of the big tube.

I'm also curious, is releasing just a bit of clutch at first gear, and the engine turns off as result also part of the issue of low on gas? Because this is not the first time it happened, it happens to me in another parking load last week, but that was before I cleaned the oil filter.

Letting off the clutch and the engine stalls is a symptom of your kick stand being down - or at least the bike thinks it is.

Low gas would account for your experience going downhill, but uphill is a different matter. There would have been plenty of gas over the pickup tube in that direction. Correcting the tube placement didn't solve your original over 40 problem.

Also, make sure there is nothing under the seat that can plug the two airbox vent holes (loose registration papers, etc.).

Letting off the clutch and the engine stalls is a symptom of your kick stand being down - or at least the bike thinks it is.

Low gas would account for your experience going downhill, but uphill is a different matter. There would have been plenty of gas over the pickup tube in that direction. Correcting the tube placement didn't solve your original over 40 problem.

Also, make sure there is nothing under the seat that can plug the two airbox vent holes (loose registration papers, etc.).

Yeah down hill just lost all power until I put on Reserve, but since the petcock tube is on one side of the tank, and both side are free flowing to each other, is it possible that during one of the hilly turns, the gas would have gone out from one side and flooded the other side, and the side that was being drained was the one with the fuel supply tube?

I think over the 40 problem has been solved, now I shift around 7k RPM instead of 5k before, and I can fairly easy get to 50 mph, however I haven't' had the chance to get over 60 yet, because I'm not yet comfortable doing freeway.

Yeah down hill just lost all power until I put on Reserve, but since the petcock tube is on one side of the tank, and both side are free flowing to each other, is it possible that during one of the hilly turns, the gas would have gone out from one side and flooded the other side, and the side that was being drained was the one with the fuel supply tube?

I think over the 40 problem has been solved, now I shift around 7k RPM instead of 5k before, and I can fairly easy get to 50 mph, however I haven't' had the chance to get over 60 yet, because I'm not yet comfortable doing freeway.

Find a non-freeway spot where you can open it up briefly and safely.

If your gas was low enough, it might have made a difference on some of the turns, but the result of no gas is usually a stopped engine not hesitation.

If your gas was low enough, it might have made a difference on some of the turns, but the result of no gas is usually a stopped engine not hesitation.

Interesting point, funny thing this has never been a issue on flat grounds, but still, so far I rode for less than 200 miles on this bike, maybe not enough time to tell yet.

But if this were true, then petcock is probably the big issue here.

On a group ride to Glendora Mountain Rd on a ninjette tech day, my 2008 model was seriously losing power in a similar way. We checked it out, found nothing, and continued on. By the time we got there it was running fine again and the problem never came back.

Find a non-freeway spot where you can open it up briefly and safely.

If your gas was low enough, it might have made a difference on some of the turns, but the result of no gas is usually a stopped engine not hesitation.

Lol your sig is censured :clapping:

Lol your sig is censured :clapping:

Don't rub it in. I think it's related to his sudden inactivity here and I'd much rather have him here than just about anyone else on the forum. It's like kkim leaving all over again. Yeah: I said it.

He put a lot of (IMO, misguided) work into a something he wanted to share, the subject of which was deemed tediously controversial and, thus, disallowed. We were tired of arguing about it here and everywhere else on the Internet and I can only imagine how frustrated that made him feel.

Don't rub it in. I think it's related to his sudden inactivity here and I'd much rather have him here than just about anyone else on the forum. It's like kkim leaving all over again. Yeah: I said it.

He put a lot of (IMO, misguided) work into a something he wanted to share, the subject of which was deemed tediously controversial and, thus, disallowed. We were tired of arguing about it here and everywhere else on the Internet and I can only imagine how frustrated that made him feel.

And yet his ninja blog link takes you right to it in his sig :rotflmao:

So? He can have the discussion there because he has to deal with that mess. No one intended to stop that.