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Fireblade 919 carb issue
watsonpj - 29/5/21 at 08:02 PM

Hi all
I've been getting my Fury ready to sell but am having some issues with the carbs which has been holding me up for over a month now. Im getting to the point I might just sell it with the fault and take the hit as my heart isn't anymore.

Anyway here is the issue.
Starts fine from cold and runs OK ish but seems to cough and splutter sometimes whilst accelerating.
The fuel pump runs up to pressure then stops suggesting float needles are sealing.
The main issue however is when I stop and switch off some of the carbs starting pooling a small amount of fuel and then you can hear a regular noise like fuel bubbling/boiling or it being pumped in.

This is only when hot not cold and once hot the car is extremely difficult to start as its effectively flooded.
I'll try and get a video and add it in.
I have already rebuilt the carbs this year.

Cheers for any help in advance.

And if anyone is interested in a Fury with a fireblade I was thinking around 5500


[Edited on 29/5/21 by watsonpj]

r1_pete - 30/5/21 at 01:10 PM

Is the fuel line running close to hot parts causing fuel to heat up between the pump and carbs??

watsonpj - 30/5/21 at 07:36 PM

No the carbs are not near any significant heat source but the car was running hot when I switched it off. It was 102C I think.

sonic - 30/5/21 at 09:18 PM

hello mate

i have a 919 in my car, i had a similar issue not long ago and it was float needles. took mine out and they looked ok, bought a new set off ebay and it cured the problem. no idea why i couldnt see any visible diiferance between old and new.
my symptoms were, started from cold no problem, when driving coughed and sluttered and if it was not wouldnt start and stunk of fuel, park in the garage it stunk of fuel overnight.

watsonpj - 31/5/21 at 10:11 AM

yep symptoms sound the same and i was thinking its the needles again but as said i have already done a rebuild at the start of the year so needles were replaced. I also cleaned the carbs fully then too and they were fine but only for a while.
I'll get another set of needles and see how it goes.

Cheers Pete

sonic - 3/6/21 at 09:20 PM

Hello mate

Did you get the problem sorted ?


watsonpj - 4/6/21 at 12:47 AM

Just got them today and fitted tonight so we take it out tomorrow and see. It runs and the pump stops after building pressure but it was doing that before when cold.
Here's hoping that does it.

watsonpj - 5/6/21 at 09:15 PM

Nope still doing the same.
I have a video of it now so will post a link but it appears to be the small hole at the bottom (choke?) where the noise/fuel is coming from. It'd like the fuel is boiling out of there.
Is that the port for the choke?
Really stinks of fuel and it's pooling in 3 of four carbs.
Actually broke down and had to wait cooled/evaporated to get home

Now it's cooled down i can see there is no hole there it was just bubbles forming in the fuel on top of the butterfly.
I have no idea what's wrong with this any more ideas before I pay someone to fix it?

[Edited on 5/6/21 by watsonpj]

[Edited on 5/6/21 by watsonpj]

[Edited on 5/6/21 by watsonpj]

watsonpj - 5/6/21 at 10:35 PM

OK here's the

This only happens when hot.
The car runs fine initially then gets lumpy and starts cutting out.
Then all carbs flood and it's a batch to restart and stalls whenever revs drop.

sonic - 6/6/21 at 10:59 PM

Hello mate have a word with Steve Bogg at Bogg brothers, he is an expert on bike carbs 01944 738234

watsonpj - 9/6/21 at 09:07 PM

Ok I feel stupid for continually cleaning the carbs when the problem was at the other end of the car, just needed to sit down and have a good think about the problem which i did last night. Suddenly realised that there was no way i could have screwed up cleaning on all four carbs and the problem was in all at the same time. So it must be something that was common to all.

The float chamber overflows return down to the fuel tank and it looks like the breather is blocked.

I thought it was when it was hot but it was actually is when i used fuel the tank would pull a vacuum on the float chamber popping the needle open.
once i switched off this would continue until the tank normalised hence the strange behaviour on the video . I just tried it out and it all seemed good so hopefully thats it.

cheers Pete

ReMan - 10/6/21 at 09:01 PM

Wow that good result.
Interesting that the overflow is piped back to the tank, would need have guessed that to be a thing even, so difficult to guess other than the suggestions you followed
Normally just flood onto the floor, not that they do overflow in normal operation

watsonpj - 10/6/21 at 09:23 PM

yeah I buit it and piped it back but wish i hadn't now as its cost me a lot of time and money tracing this fault but it went really well last night.
Probably needs a bit of a tune but its pretty close, I need to clean up the plug and run it a bit and see what colour they are as up to now they have just been wet.