Carb. Overflow!!! TTR 125

[WVyamaha89]

Welp, warm weather has given me the chance to work on the Ol' TTR. Too bad the problem I thought I fixed, was not fixed at all...Heres the deal.

1. Carb was cleaned thoroughly.

2. Needle valve was stuck, now is fixed.

3. Everything re-assebled perfectly.

4. STILL OVERFLOWS!!!

Anyone help me with this???

[RynoMX]

It sounds like the float valve is not seating. Check the float for any debris, check the adjustment and while you're there, make sure the float floats. Simply hold the float under some water in a bowl or bucket and watch for bubbles. I once had one with an unseen crack and the only way to find the problem was to put it in water.

[WVyamaha89]

Welp, The whole thing is spotless. and the float..well floats haha. I simply shut off the needle valve by hand and well...the gas pours right out...guess I need a new needle valve?

[DadRider]

Yeah you might need a needle and seat. You could put a hose on the fuel inlet to the carb, with the float bowl off, and blow on the hose to the carb, and then seat and unseat the needle? How high does the float have to go before the air flow "shuts off"? Maybe the float tang that moves the needle against the seat needs a tweak?

Kind of simulate with low pressure air instead of fuel and see what the float / needle assembly is actually doing or not doing....

Might want to put an inline fuel filter on there before you put it back together next time, just in case sediment or something is getting to the needle valve.

[RynoMX]

I think you've solved the problem. If there's no debris and the actual float is not the problem and gas still pours out by manually closing the valve then I would agree with Dadrider that the valve and or seat needs replacing. Make sure that the float is adjusted within spec. That's done by bending the metal tang, just like Dad said.

[WVyamaha89]

I fixed the needle valve, so there is no more overflowing haha. (one problem down) . Any tips on how to set everything up, I understand where the idle screw and pilot screw is and what it all does, but dont really know any procedure on how to even go about adjustin and fine tuning these to get it to idle and run right. I got the engine running and took a lap around the house...she's bogging down quite a bit but I'm guessing tht with the proper adjustments on the idle and pilot she'll be fine.

[RynoMX]

Do you have a manual? I can't find my at the moment. Hopefully you counted the turns on the fuel screw to lightly seat it prior to disassembly of the carb.

The manual will tell you the initial opening for the fuel screw (in turns out from seated) i.e 2 to 2 1/2. Start the bike and using the throttle screw, set it to the suggested RPM, i.e. 1300 +/- 100. Then turn the fuel screw in or out to get the highest rpm, then reset the RPM to factory spec using the throttle screw. The specs I listed are only examples, reference the manual or another TT member will give them to you. This is for a stock set up, no mods. With mods you have to dial in the pilot and main jets before tuning.

[WVyamaha89]

I did a simple airbox mod. (remove snorkel and cut a bit of the airbox). would I need to do anything as far as needle height?

[RynoMX]

If its simple and not radical, you might be OK. More air in will create a lean condition which means larger main jet to introduce more fuel to get the right ratio. You can do a plug chop test to see if you have the correct size main.

[WVyamaha89]

Very simple...just a few holes in the cover w/ a screen behind it...may not even do much if anything but that it as far as modifications

[RynoMX]

That doesn't sound too rad. If you're using the stock jets, I would recommend changing them to a larger size. If I remember right, I used 17.5 pilot and a 110 main on my son's stock set-up. Some people will run slightly larger or smaller jets, all depends on location and the bike itself.

[WVyamaha89]

Yeah i figured. seems to be running fine now after foolin with it most all day. I know doing mods and all that to a bike have its advantages and disadvantages, but hey, I've already noticed a big change since the last time she ran haha. thanks for the help man. I've been hearing alot about changing the pilot and main on here so I'll give it a whirl. I'm still learning ?

[RynoMX]

doing the jets is an easy cheap mod and you'll notice a difference. Next will be frame cradle, pipe, bigger carb, big bore kit, etc. Its never ending. Have fun tweaking the bike.

[WVyamaha89]

Thats the whole reason I bought the bike ? If it ain't broke...it's no fun haha

[DadRider]

Ok...so how did you fix the needle valve?

[WVyamaha89]

Welp, i don't know if I've said this already but I didn't know jack about carburetors until I got this bike. so turns out I didn't get the needle valve free. I thought the spring loaded button on top was the part that needed free haha but I found out what in the world I was doing and got it moving again. Just took a good bit of effort to remove it (thus the reason I thought it was supposed to be like that) and used some cleaner, Q-tip and some air to clean it right up. I feel like such a you know what, but hey...gotta learn somehow

[DadRider]

Congrats, glad you figured it out. That's a good lesson you'll always remember. Experience is a great teacher.