2004 carb flooding issue

[Horizon]

Hey,

I've been struggling with my carb for a while now, it's my first project bike and it seems like a pretty niche issue.

Carb floods quite a bit on prime, basically just pisses out the airbox drain pipe. I haven't managed to do a proper test with the vacuum petcock set to "On" since it seems like not enough fuel is getting through it after rebuilding it. Need to double check the setup there but the flooding issue seems excessive.

- The needle and seat is a brand new tourmax replacement and the 2nd replacement I've put on them. I was careful, they are in good condition.
- The floats don't show any leaks at all when submerged in warm water, they have good buoyancy but are the original floats.
- Needle slides nicely and doesn't seem to have any issues/catching/etc
- I can't blow in the fuel tube if I'm resting the float even slightly on the needle like when you're mesuring float height
- It also seals when the pressure is low enough, roughly a clear fuel inlet pipe showed the level would settle around the top of the carb airbox ports and stop flooding, almost at tank level but not quite.

I feel like I need to go out of the usual float height spec for this, I did try put it up a few mm before with my aux tank but it still leaked, not sure if the seal level was different as I didn't realise it sealed at all at the time.

I was wondering if anyone has dealt with a similar issue and has some kind of direction I can go?

[Armandorf]

a clear fuel inlet pipe showed the level would settle around the top of the carb airbox ports and stop flooding, almost at tank level but not quite.

gas level should be inline of the bowl gawsket, with a u pipe connect to the bowl drain screw

[Horizon]

Fair enough, I'll give it a go trying to set the height using the clear pipe trick, I guess if setting the float height in spec doesn't work I don't really have a choice.

Thanks

[Horizon]

I've put the float height up to 17mm and it still just pisses out, I can only assume the floats don't have the bouyancy to close the seal.

I'll have to look at replacement floats but I'd rather not pay £100~ for OEM

Does anyone happen to know a decent budget replacement?

[Armandorf]

clean the bronze float valve seat , you can polish it  with fine steel wool, i use a wooden brochette stick(wide toothstick) with a rotating motion,pushing slightly till it deforms

[moe_tunes]

If you shake the floats and don't feel fuel sloshing around inside then they are ok.
Are the o-rings that seal the seats to the carb body ok ?
I like mikunioz for carb parts.

[Horizon]

Thanks for the input, I've had a play and I'm still not fully there yet

The floats definitely don't have leaks or anything inside them.
I can't hear or feel anything while shaking, or see anything while shining a torch on them.
I've put them in warm water before and had 0 bubbles and they felt fine then too.

I've tested the needle and seat with a bike pump + pressure guage, they are sealing and holding just under 20psi, any higher and the pipe pops off my pump. If I lift the float the pressure drops and I can hear it rush out the valve. With less gravity on the floats they only leak air once they push the float out the way, I can see it happening.

I'm fairly confident the seal is not the issue, so to me the only thing it could be is the floats are just heavier than they use to be and can't fight the downwards pressure of the fuel. If setting them to 17mm (instead of 13mm spec) doesn't make any difference I can't imagine what else it can be. 

I did have a look at the main jet o-ring and it seems fine, not really sure how I'd test it but regardless it's a new o ring and it's seated where it should be.

I've ordered a couple pre-used OEM floats for £20 and hopefully they contribute at least something in the name of figuring this out. If those don't make a difference I guess I'm measuring the bouyancy of all 4 of them against weights in water

[Horizon]

Got the new (pre-used) floats and had a play with them as well, exact same issue.

I tried dropping the bowls and pressing the floats manually and the flow stopped completely.
I didn't even need to press them hard or all the way in, just enough to seat the needle.
I'm 100% confident in the valve.

I've double checked the O-ring on the main jet, cleaned out where it seats and put put it on decently tight until it felt like it completely seated.

I'm still thinking it has to be a float failure but... what are the chances I have 4 OEM floats that all weigh the same, none show any leak but they all just completely fail to push the needle up. There's no friction, effort or catching in either the needle or float when I'm checking it myself.

It seems completely illogical so I must be messing something up but I can't think of anything else that could even impact this.

I think maybe next I'll try give it a go with 1 float pushed up manually and try see if any single float can hold itself in the bowl.

[Horizon]

So fun news, I solved it.
All 4 floats are fine, I now have a couple spares I need to figure out what I'm doing with.

My months of head scratching and part replacement turns out to be....
I plugged the vent pipe when I did the EGR delete.

Thanks for the input and I've learnt a good lesson... lol