Viper 150CC w/New Mikuni 30MM leaking gas

[InfiniteBPS]

Hi I am new to the ChinaRiders forum. I recently bought a used 2020 Viper 150CC that had barely been used by previous owner. Previous owner didn’t drain fuel from OEM carb before storing. Then they could get it to run so they removed carb and threw away then never found a replacement carb that fit. I bought the dirt bike did some searching on internet which brought me to ChinaRiders where a I read folks recommending upgrade from OEM 27MM carb to a Mikuni 30MM carb. I got the Mikuni 30MM installed and finally got dirt bike running and went for short ride to make sure it shifted thru all gears and it pulled pretty good. The issue I am having is when I come to stop engine bogs and does. I notice fuel was leaking from bowl drain screw so I tightened it which stopped that leak. Now with the engine not running if I turn fuel on I have steady flow of gas from overflow needle. The carb is at a slight angle off from being level so I thought maybe the angle was messing with floats causing the overflow of fuel. I put a 2x4 under front wheel to level out the carb but now the fuel is pouring out of the air intake side of carb. Should return carb for a new one?
Does anyone know if there is an adjustment I need to make?

Many Thanks in advance for any advice

[Bruces]

Your inlet needle is probably stuck ,take the bowl off ,and fix it .Your carb is way too large for a 150cc china bike ,nobody on this site recommended a 30 mm carb for a little 150 ,we don’t even recommend them for most 250cc China bikes .

[Thumper]

OEM carb if you can find one. 27mm ??


Head work and opening up exhaust will do more for adding useful power.

[InfiniteBPS]

Originally Posted by Thumper

OEM carb if you can find one. 27mm ??

I bought one OEM from a viper dealer but it leaked from overflow needle and bowl drain screw. The bowl screw heads were stripped off so carb was unserviceable. I bought another PZ27 off Amazon which leaked from drain plug screw and had signs previous owner also had issue with leaking drain plug screw since it was almost completely stripped.

Head work and opening up exhaust will do more for adding useful power.

Not really looking for performance upgrade. Just a carb that doesn’t leak out the box or is this a normal occurrence to have figure why a brand new carb leaks out the box?

[InfiniteBPS]

Originally Posted by Bruces

Your inlet needle is probably stuck ,take the bowl off ,and fix it .Your carb is way too large for a 150cc china bike ,nobody on this site recommended a 30 mm carb for a little 150 ,we don’t even recommend them for most 250cc China bikes .

You are right! When I went to original thread I noticed the original post was having issues with a 200cc dirt bike.

I take it a 30MM is too big for a 150CC dirt bike?

Any preferred manufacturer for quality 27MM?

[Fast_Freddy]

A new carb shouldn't leak. Return it for a 26mm carb appropriate for your bike,

[InfiniteBPS]

Originally Posted by Fast_Freddy

A new carb shouldn't leak. Return it for a 26mm carb appropriate for your bike,

Thank you for advice…..Return started.