2001 Yz125 pissing gas out overflow

[Bryan D2911]

I recently bought a 01 yz125 bikes mint just the carb pisses gas out the overflow, I pulled my carb out and gave it a good clean reasembelled it and put it back on. It was fine not leaking gas anymore so I went for a ride on it and it was fine for about 2 hours until I went to lean it up on a tree. Next thing i know its pissing gas again, anyone got any suggestions on what the issue may be? I'm thinking it's just dirt getting into the float somehow but I dont know where. I was thinking about checking the gas tank to make sure there isnt dirt all in there aswell.

[RichieGoatGruff]

41 minutes ago, Bryan D2911 said:

I recently bought a 01 yz125 bikes mint just the carb pisses gas out the overflow, I pulled my carb out and gave it a good clean reasembelled it and put it back on. It was fine not leaking gas anymore so I went for a ride on it and it was fine for about 2 hours until I went to lean it up on a tree. Next thing i know its pissing gas again, anyone got any suggestions on what the issue may be? I'm thinking it's just dirt getting into the float somehow but I dont know where. I was thinking about checking the gas tank to make sure there isnt dirt all in there aswell.

If it's a mikuni, you probably need a new oring for the float needle seat... It probably needs a jet block gasket, too. Just get the mikuni jet block kit from james dean.

[Smoking 2's]

Float level maybe in need of adjustment. Might be right on the line where straight up its fine but any slight lean and it dumps

[CaptDan]

7 hours ago, RichieGoatGruff said:

If it's a mikuni, you probably need a new oring for the float needle seat...

The O-ring was the culprit in our 2001. 👍  It was dry and porous; pretty obvious once you inspect it.

Unfortunately, you have to buy the entire valve just to get the O-ring. 👎

You may be able to find a suitable O-ring at a good hardware store.

Good luck, and keep us posted with what you find. 👍

[Rod21]

Other than mentioned above, look into fuel inlet to float needle seat passage with a flashlight. I had some rubberized crap in there keeping needle from seating. Regardless, blow that area clean with compressed air from both ways.

Edited July 7, 2020 by Rod21

[Sullysully]

1 hour ago, CaptDan said:

The O-ring was the culprit in our 2001. 👍  It was dry and porous; pretty obvious once you inspect it.

Unfortunately, you have to buy the entire valve just to get the O-ring. 👎

You may be able to find a suitable O-ring at a good hardware store.

Good luck, and keep us posted with what you find. 👍

Yup. I tried to find a suitable o ring. It’s a very specific size.

[mr.blaze]

float height can be wrong, the float needle/seat may be worn out.  it is almost always one of those 2 things if its pissing out the overflow

[Bryan D2911]

Ok thankyou all for all the help I'll keep you updated on how it ends up.

[RichieGoatGruff]

50 minutes ago, Bryan D2911 said:

Ok thankyou all for all the help I'll keep you updated on how it ends up.

Buy this....

https://jdjetting.com/product/jdmk05-mikuni-tmx-jet-block-kit/

[M E T A L A C I D]

14 hours ago, Bryan D2911 said:

I recently bought a 01 yz125 bikes mint just the carb pisses gas out the overflow, I pulled my carb out and gave it a good clean reasembelled it and put it back on. It was fine not leaking gas anymore so I went for a ride on it and it was fine for about 2 hours until I went to lean it up on a tree. Next thing i know its pissing gas again, anyone got any suggestions on what the issue may be? I'm thinking it's just dirt getting into the float somehow but I dont know where. I was thinking about checking the gas tank to make sure there isnt dirt all in there aswell.

You mess with da floatie arm tang? If you did, return it to the stock setting, and dont mess wid dat floatie arm again..