125 Exhaust coming out of power valve drain tube
- Thread starter AkYz125Ripper
- Start date
I used a caliper to measure the float height. And big dan, it only bogs 1/4 to 1/2 throttle. Once it catches on and i hold it WFO it does real good, til i let off on it.
cool , you used a caliper. what measurement did you set it to? to my recollection yamaha does not print a measurement that involves a caliper without a sight tube. was the spring tip depressed on the float needle etc. Is the carburetor the stock one?
When you say it bogs when you are at 1/4 throttle do 1/2 throttle, does that mean when you roll open to that throttle setting, or if you hold it anywhere in there constantly?
When you say it bogs when you are at 1/4 throttle do 1/2 throttle, does that mean when you roll open to that throttle setting, or if you hold it anywhere in there constantly?
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Was the power valve taken apart and cleaned thoroughly then reassembled properly? How long has it been since it's had a fresh top end?
Since it doesn't flood out or run out of fuel when on the pipe I'm not thinking the floats were the issue... Then again I was married for 14 years so I'm used to being wrong...
Since it doesn't flood out or run out of fuel when on the pipe I'm not thinking the floats were the issue... Then again I was married for 14 years so I'm used to being wrong...
How are the reeds? Have they been checked?
oh just for the future i never give advice on marriage. so far I havent seen anything that would indicate that the yz isn't going rich or lean.
What I see happening frequently is the bike running rich throughout, the owner not knowing why jets down on top. you can fill in the rest. it may not be the case here, but I start at the cheap spots until i have more to go on. I would bet that if the owner marks the throttle between 1/4 and 1/2 (most are only guessing on that setting until the mark it off) the owner may be able to see if there is a rich or lean condition at that setting and can go from there. could be the float setting, could be brass related. so far i havent seen that he inventoried while he was in there to see how far off or on stock he is on jetting. That can be a tipoff too.
I am not doubting the part about the valve, but I have had lots of bikes that didn't have exhaust power valves act similarly and even the worn out ones can be made to run clean down there if they can run clean on top in almost every case. I see lots of people who rebuild (which is always nice for power) and clean up another condition a little and think that was the whole problem the whole time. 5 hours later, same thing.
The mikunis have that fuel passage behind that emulsifer/needle jet holder that gets partially blocked as well.
What I see happening frequently is the bike running rich throughout, the owner not knowing why jets down on top. you can fill in the rest. it may not be the case here, but I start at the cheap spots until i have more to go on. I would bet that if the owner marks the throttle between 1/4 and 1/2 (most are only guessing on that setting until the mark it off) the owner may be able to see if there is a rich or lean condition at that setting and can go from there. could be the float setting, could be brass related. so far i havent seen that he inventoried while he was in there to see how far off or on stock he is on jetting. That can be a tipoff too.
I am not doubting the part about the valve, but I have had lots of bikes that didn't have exhaust power valves act similarly and even the worn out ones can be made to run clean down there if they can run clean on top in almost every case. I see lots of people who rebuild (which is always nice for power) and clean up another condition a little and think that was the whole problem the whole time. 5 hours later, same thing.
The mikunis have that fuel passage behind that emulsifer/needle jet holder that gets partially blocked as well.
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