TTR 125 Carb Overflow Issue - Plz Help!

I just picked up an 03 TTR125LE that didn't run because it had been sitting for a long time.

Since picking up the bike, I've rebuilt the carburetor. Completely disassembling it and cleaning all the parts with carb cleaner. I replaced the pilot jet with a 17.5 and the main jet with a 110. I've also replaced the needle valve because the old one was completely gummed up. I reassembled everything and set the float height.

The bike starts up great but after running for a few minutes, gas starts coming out of the overflow valve pretty quickly and the bike stops idling and dies. Even after the bike dies, gas continues to flow out of the overflow hose. I also cant start the bike once this happens. If I turn off the fuel and leave the bike for several hours, the bike starts up fine again, but will start overflowing gas again.

I've checked the float height several times, it seems fine according to the manual. I'm out of ideas, any help would be much appreciated.

If it's overflowing, something about the float/needle isn't right. Can you replace the float seat on these carbs? I'd take it apart and re-inspect the needle valve and seat. That's where the gas is coming from. Question now is why isn't it stopping the gas flow?

I replaced the needle and the seat as a set. Is this the only way that gas can get into the float chamber? So if its overflowing, it has to be a problem with the needle valve?

I believe so. I'm not the greatest carb guy, but I believe that the entire purpose of the float/needle assembly is to let fuel into the float chamber and then stop the flow when the chamber is full.

If your float height is set wrong it could be letting fuel in. I don't really know how to set that though.

If you don't get enough info here, you might try over in the >>jetting forum<<.

Where do you find the specs on the float hight. The manual I have only shows how to measure the level of fuel with a clear hose. I would like to know if my problem, similar to yours, is from the float or the needle valve.

Make sure the needle is not sticking in the open position. Tap the bowl lightly with a small screwdriver handle to see if the fuel stops coming out of the overflow. It is possible that the spring on the float valve clip is facing the wrong direction and making the needle stick open. You can try taking it apart and rotating the spring on the needle 180 degrees. There was a picture on one of the posts, but I can't find it.

Good Luck

Mark

There is no fuel pump to go berserk and over-pressurize the system. The needle and seat are the sole means of of stopping the gravity fuel flow.

So, it has to be either a needle and seat that are not sealing, or a float height that is way off.

You really don't have to change the little tang on the float. If it is straight out and aligned with the rest of the body of the float, then the level is close enough. I suspect that you have that part a little off.

This carb comes off in under a minute, so the fix isn't painful. Can you take a picture of the float where the needle attaches?

The floats on your bike ride REALLY close to the sides of the bowl, mine was doing that and all I did was remove the bowl, straighten everything out made sure the float pivot pin was equal on both sides (not sticking out on one end) and put it back together... Also mine has a little plastic cone shaped plastic on the main and mine was falling off... make sure its right also...

While the bowl is off turn on the fuel and try to stop it by pushing up on the float if your seat continues to leak you know its that part... if it stops you know its either adjustment or a stuck float...

The floats on your bike ride REALLY close to the sides of the bowl, mine was doing that and all I did was remove the bowl, straighten everything out made sure the float pivot pin was equal on both sides (not sticking out on one end) and put it back together... Also mine has a little plastic cone shaped plastic on the main and mine was falling off... make sure its right also...

While the bowl is off turn on the fuel and try to stop it by pushing up on the float if your seat continues to leak you know its that part... if it stops you know its either adjustment or a stuck float...

the float CAN wedge against the side of the bowl if it's off. That's a great point.

When the carb is off, blow into the fuel intake pipe and move the float closed. You can tell instantly if the needle is blocking the flow of fuel. After that, it has to be float level.

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