Author Topic: carb leaking  (Read 866 times)

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Offline yosemite

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carb leaking
« on: 16 Oct 2019 at 16:50 »
    Recently  the mark 4 started giving carb issues( turned out to be water )so I stripped, cleaned and rebuilt them, now they are leaking from the union nut. I rebuilt them using new fibre washers, aqs the old ones were broken when I strpped the carbs. Apart from this the bike is running as well as ever. I have tried tightening the nut further but am worried about overtightening and damaging/ stripping threads
At first I suspected the float needles were not sealing properly so I changed these for new ones but this had no effect.
could anyone make a suggestion as the cause of the problem?
Paul

Offline douglas1947

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Re: carb leaking
« Reply #1 on: 16 Oct 2019 at 17:56 »
Paul,

is it leaking on top of the nut?
May be the petrol level is too high in the carb.
Please check the float  is it tight),
the lenght of the needle and position of the slot for fixing the float.

Is the cone (in the float bowl top) for the needle good enaough?

Michael

Offline eddie

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Re: carb leaking
« Reply #2 on: 16 Oct 2019 at 19:55 »
Paul,
         Check out the guide hole for the float needle in the bottom of the float chamber. With time, it can get partially blocked by debris that pushes the needle to one side, so that it doesn't seat properly.

  Regards,
                  Eddie.

Offline Eric S

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Re: carb leaking
« Reply #3 on: 17 Oct 2019 at 07:36 »
Start simple
When I worked on my carb, it was leaking. It was after several attempts I realised it was not tight enough. I tend to be too gentle on screws as I fear they fail.

Offline yosemite

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Re: carb leaking
« Reply #4 on: 17 Oct 2019 at 16:09 »
Thanks for the suggestions, the leak is from above the nut, the needles are new, the seats were checked and left a decent "witness" mark when the needles were rotated against them with the float chamber of the carb the float can be heard moving if shook gently so I assumed there was no restriction that would stop the deedle lifting freely I will have a look to see if there is any debris in the guide hole. is there a way to check the fuel level? I would guess I would have to use a modified float chamber holding bolt and some clear tubing?
Paul

Offline Eric S

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Re: carb leaking
« Reply #5 on: 18 Oct 2019 at 07:31 »
Another easy check maybe, check for the float to be not porous and filled with petrol.

Offline yosemite

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Re: carb leaking
« Reply #6 on: 18 Oct 2019 at 22:06 »
cleanfloat bowls thouroghly, some minute particles of debris in the bottom of 1 and some more in the needle seat area of the otherreasssembled and now seem fine fingers crossed
yet again thanks to all for the suggestions
Paul

 

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