New Carby Leaking Gas?

[LuckyGirl]

I have a Lifan 125cc engine, Mikuni 26mm carb, with 7 hours on it, new everything. Had it professionally tuned before I put it away for the winter. It ran like a champ before I put it away. Started it up in spring, and rode it around, before noticing the sluggish/bogging throttle. Stopped the engine and noticed gas pouring out of the drain tube and air intake. Pulled the carb apart, cleaned the living crap out of it, same thing happened. Float needle was free and there was not a speck of dirt in it. Gave up and bought a brand new carb, same thing, leaking gas out of the intake and drain tube. I didn't take apart or touch the new carb. The new Mikuni 26mm carb was bolted on with the stock settings. The bike starts and idles, but leaks gas. What is wrong? What do I do? Why is this still happening with a brand new carb?

 

[zwebx]

Its because the float level is set wrong..
How that is set is where the needle and seat attach to the float, by a little metal tab. To set the fuel delivery lower all you need to do is bend the tab a few degrees up so when the fuel lever rises it does not get to the level of the overflow or too far above the jet.

It needs to be set even with new carbies on all bikes most of the time, its apart of ownership really.. however once it is set correctly you may not need to think about it for years, untill you clean it and accidentally bend the tab. or have flooding while jumping etc..
Im sure my67xr will tune in too with pics etc..

Try to make the fuel level about level with the bottom of the jets..

 

[my67xr]

Maybe try tapping the fuel bowl with the handle of a screwdriver a few time's to see if it come's good.

Other wise you'll need to pull the bowl off and bend the centre tab on the float arm up a little more so the floot closes the needle into the seat earlier.

The china Mikuni 22/26 carby run with the float level at about 23mm - 25mm

The centre tab is the one that adjust's the float height

You can check the float level if you have some clear hose handy.
Fit some hose onto the drain tube on the bottom of the fuel bowl.
Hold the hose up near the top of the carby, undo the drain screw on the fuel bowl and measure how much lower the fuel level is compared to the top of the fuel bowl

 

[LuckyGirl]

You guys rock! My float tab was bent the wrong way. Runs like a champ again! Thanks again!!

 

[velociraptor]

Am I the only one asking here if it was professionally tuned why they left the float tab bent the wrong way?

 

[Cordogs]

They didn't, that was the old carb.

The new one was bent.

 

[velociraptor]

Ok. But why was the old one bad maybe bad float needle or seat maybe?