x-pro 125cc Bogging full throttle.

[Gm5moker]

Hey Guys,
I have a brand new x-pro Vader 125cc.It has a real Mikuni vm22 from summit racing,emission delete.At full throttle it bogs down,and for the life of me i cannot figure it out.I've tried main jets from 95-150,no difference.I install new fuel filter, spark plug, checked the vent hose coming from top of fuel tank,place the needle ring at the bottom,turn the fuel mixture out 2.5+ turns and nothing changes the bog. the bike runs good other then full throttle bog. i'm lost for what to check next,any help would be awesome.thanks!

[4T_Goblin]

Did you check the float level?
What kind of bog is it? Lean or rich? I'm guessing lean
When you say bog at full throttle, do you mean when you snap open throttle? Can you describe this moment in more detail

[Gm5moker]

its when you snap it open full throttle.if you ease into the throttle it'll work sometimes. it bogs almost where it dies then it'll catch itself. yes i checked the floats aswell.

[Gm5moker]

https://youtube.com/shorts/SOWqbBALXdg?feature=share

[clash 168cc]

Look in the throat of the carb and see if its spraying gas when you go full. Put your hand over carb while throttling up. Leaking intake gasket? Valve adjustments off?

[Gm5moker]

Originally Posted by clash 168cc

Look in the throat of the carb and see if its spraying gas when you go full. Put your hand over carb while throttling up. Leaking intake gasket? Valve adjustments off?

The spark plug is black. I’m guessing it’s rich? But if it was rich it wouldn’t be bogging like that?

[clash 168cc]

Originally Posted by Gm5moker

The spark plug is black. I’m guessing it’s rich? But if it was rich it wouldn’t be bogging like that?

Take the filter off and put your hand over at varying degrees to see if it will rev better.

[clash 168cc]

Originally Posted by Gm5moker

The spark plug is black. I’m guessing it’s rich? But if it was rich it wouldn’t be bogging like that?

Put a spark checker on to see if it stops sparking when you rev.

[Gm5moker]

Originally Posted by clash 168cc

Take the filter off and put your hand over at varying degrees to see if it will rev better.

It’s spitting fuel. No putting hand over it don’t help.

[clash 168cc]

float may not be shutting off and over flowing bowl. Recheck needle and seat. You might just buy another carb.

[clash 168cc]

Pinch off fuel line and see if it starts revving better before it runs out of fuel.

[4T_Goblin]

Is the choke on or off

Black plug is rich- that could be from flooding in the float valve. Like the valve is stuck open.

Genuine mikuni carbs like lean jetting - what size jets are you running?

That's a lot of air in the fuel line too

[Gm5moker]

Originally Posted by 4T_Goblin

Is the choke on or off

Black plug is rich- that could be from flooding in the float valve. Like the valve is stuck open.

Genuine mikuni carbs like lean jetting - what size jets are you running?

That's a lot of air in the fuel line too

Choke is off
It’s got a 115 as main jet in it. I’ve tried everything from a 100- 130 or so.

[4T_Goblin]

There is a lot going on here. Try and look at one circuit at a time.

From watching the video it looks like you don't have good fuel flow. Remove the fuel line from the carb, turn the fuel on, let the fuel run through and fill up the line try and get rid of the air bubbles then put the line back on the carb

But first you make sure your idle is good with the pilot jet, check your AF mixture. You describe rich spark plug, that could be too rich at idle. Verify the float level and that the float valve opens and closes properly. Verify the amount of turns out on your AF screw.

Once you have good fuel flow your can move on

Snapping the throttle open in neutral is not a good way to test your circuits. You need to be riding to really tell

[Big Bird]

Probably leaking at the flange since the manifolds on these bikes have a offset and a genuine mikuni is centered. Spray some carb cleaner at the flange while reving it up and see if the rpms start to die.