Carbs leaking petrol from air jets and float breather?

[Jpich85]

Sorry to post another problem but I don't know who better to ask than the guys on here.

After fitting some bigger jets that legotoy kindly sent me and after giving them a good clean, I hooked everything back up and primed the float bowls but when I tried to start it petrol was coming out of the float bowl breather and the little air jets that are in the housing where the pod filters go, I had this problem last year after fitting all new seals and I after messing with the float valve and pushing things in and out again it stopped but now it's back lol. I just wanted to know if anyone knew what's causing this because I got lucky last time and don't really want to do it that way again, it's like the petrol isn't shutting off and petrol is over filling the bowls. The o rings are fine because there all new and I haven't rode the bike yet unfortunately. Cheers

James

 

 

 

 

 

[Gixer1460]

O rings may look good but could be leaking but usual suspect is the float valve - replacement time! And that could have been the cause of the rich running condition in your other post - just enough to richen but not flood - now its worse!

Edited September 22, 2016 by Gixer1460

[KATANAMANGLER]

Take the valve needle out and inspect it for a groove on the runner tapered tip. It shouldn't have one.

[Jpich85]

Thanks got getting back to me, I did check everything over and the float valves look good still in brand new condition really, I haven't used the bike yet unfortunately so not much wear on things, legotoy mentioned a stuck float?

[Jpich85]

Is it important where the float valve sits on the float tang?

[KATANAMANGLER]

Have you adjusted the float height? or has anyone else adjusted the float height in the past? Worth checking the float height. What carbs are they? RF900?

[Madb]

I was just about to ask that question.

On the question about 'where it sits on tang" if yer carbs are upside down when you assemble them they should be nicely centred. Just check the metal clip from float valve is on the tang.

Edited September 22, 2016 by Madb
Spelling. !!

[Jpich85]

They are gsxr 750 carbs and I did do the float heights, 15mm is what I thought they had to be? Thanks I'll check them again, I'm sure it's something simple but a pain that another problem has happened lol, I did drain the bowls and a lot more came out of one carb compared to the rest

[KATANAMANGLER]

Carbs tend to have cascading problems. You fix one and while fixing that you create a new one.

[Sheep]

Out of curiosity do you have a filter in your fuel line?..O rings may be new,floats may be as new but if you have a little bit of debris come through it could hold the valve open.

 

[Jpich85]

I got some time to work on the bike this afternoon and I fixed the petrol leak problem :-).

There's a different leak now tho but only on one of the carbs, I'm getting petrol slowly build up against the butterfly? It was fine at first but I was changing the oil due to petrol contamination and I pulled the plugs and hand cranked it then noticed this little fuel build in by the butterfly? I changed the o ring by the emulsion tube, do you think it's that, where petrol may be seeping up through?

There is a fuel filter sheep built into the petcock.

 

 

 

[Madb]

Any progress?

[Reinhoud]

Before putting carbs back on, put fuel line on carbies, hold them up side down, and blow with your mouth into the fuel line. You should have no leak.

[Jpich85]

 

Yeah I have sorted it now thanks boys, I'm thinking that the floats were stuck, I stripped them and reassembled them making sure I tapped the bowls before filling them and they were fine, I've learnt a lot and not so scared about messing with the carbs anymore, those jets that legotoy sent me work a treat too, I'll need to fine tune it tho when I get it on the road, I did have an issue tho when I put them back on the bike where it would only run with the choke, it was only the throttle cable tho that was too slack so bit of a school boy error there lol, bikes running nice now so I can move on to the sorting out the hard rear suspension due to the hayabusa swingarm :-)

[Madb]

Cool. What size jets you using?

[Legotoy]

147.5 main jets at the moment (what I sent him). Glad it's running better now!!