Our Yamaha ttr 125 2001 will not bring gas from the float bowl into the carb. Is there a power valve on a Mikuni 5HP1-00JD?

Many things can cause this;
check the following.

1. trash(including rust in the tank if metal) in the tank/carb. If the carb set for more than 6 months it may need the fuel system cleaned out(includes the carb). Putting a filter in the system will not take care of the rust problem in most cases. If the tank is metal and has rust it will need a tank liner kit like the brand "kreem" or the equivalent.
2. the needle/seat combination and/or float is incorrectly set or bad causing that fuel level to get high in the bowl. Check the float height according to the manual or replace the float/needle/seat.
3. bad seat o ring if it has one and also a petcock that does not shut off. If you can jog the seat around in the carb, then the o ring is probably bad. If you disconnect the fuel line from the carb and gas still comes out, the petcock is most likely bad or it has trash in it.

Remove the gas tank shut off valve and clean it or replace it. The filter in it must be clogged.

Gas running out the puke tube indicates debris in the float valve(Stuck Float)
some just tap the side of the carb and it passes through, some take the carb apart, clean it and reassemble it.

In your case, remove the carb, remove the bowl from the carb., remove the float pin, then the float, and the float valve/needle is hanging on the float tab.

now blow through the tube that the gas line hooks to with compress air to clean out that passage.
air should blow out the hole that the float valve was in.

Reassemble.

You will not have to remove any jets to clean the float bowl chamber.

i suggest you blow through every opening on that carb while you have it off to make sure nothing is clogged.

Your float will now shut off the gas flow like it should, and quit coming out the puke tube.

hi,sounds like the float in the carb is stuck in the fully open position,you will have to take the carb out,take the bowl off the bottom of the carb and inspect the float needle assembly,the little clip that holds the float to the needle valve may have come off,allowing fuel to run unchecked into the carb and ultimately out through the overflow..hope this helps..cheers