carbs

[paulmceleney]

hi lads fuel is pouring out of the float bowl on one of the carbs looks like the float not shutting the fuel off, what would cause this, as many answer as possible before i take it a part cheers

[Pigford]

Bit of sh*te from tank stuck in float shut-off valve

[tlc]

Agree with Mark.

Same thing happened to me first day out last year. Not a job to do at the side of the road. Ask Bunny

[Z1B Alan]

Agree with the above you need to clean the needle jet out as a small piece of dirt is probably stopping it from seating / cutting the fuel supply. You could try switching off the fuel then take the float drain plug out of the offending carb then allow the fuel to run through the carb for a while in order to flush the carb out. Its worth a try before you pull the carbs off if successfull install an inline filter as this can avoid a multitude of problems.
Regards
Alan.

[paulmceleney]

Thanks lads put the carbs on last night these are 33 smoothbore carbs and they have been sitting on a shelf for a while

[Steve Cooke]

Paul you shouldn't really get anything through the tank/tap if the filters are ok, but I did have this happen to me once and found that it was a tiny piece of rubber that must have nicked off the inside of the fuel line when I'd pushed it on and it lodged itself between the needle and the seat. Did you check the floats and needles weren't seized before fitting them?
Inline filters are a good way to go.

[Z1B Alan]

Just a quick extra to check if the float valve proves ok it is possible that the overflow pipe is cracked this has been the case on here before.

[bunnysZ]

or a cracked copper pipe inside the float bowl, swap the bowl and see if it happens to the one you swapped it with , if not then you know its not that , . or adjust the butterfy float , or make sure the needle bit has been put in the right way around ,

[Rich]

Thanks lads put the carbs on last night these are 33 smoothbore carbs and they have been sitting on a shelf for a while

33 sbores like 29mm have little mesh filters above the fuel valve in each carb so I would take the valves out of all of them and check the mesh, valve float pivot and adjust fuel height. They don't have overflow pipes.

http://www.allensperformance.co.uk/exp-vm33.html

[paulmceleney]

Thats correct rich no over flow pipe, i have taken the bowl off the carbs and the float is dented so i was think of swapping the floats over to see if this was the problem if this the case the carb with the dented float should over flow ,can you still buy them ? thanks

[Rich]

Yes you can

http://www.z1enterprises.com/Mikuni-Bra ... ly-75.aspx

[paulmceleney]

still have problems, right swaped floats over still leaking ,removed float bowl fitted carbs on to bike held float in and still petrol will not stop running out anyone

[Al]

Do they have 'O' rings round the float needle seats?

I have had to replace these on RS's and on my CV's for the same reason that you have been experiencing.

If you have 'O' rings on them and you pull the seats out easily by hand or they fall out under the pressure head of fuel above then these will be the cheapest of replacement options of the many possibilities.

Got mine from NRP.

Another thought is that i had replacement needles and seats as 'new' parts.
The dimensions of the new needles and seats wasnt the same as originals. That meant that you couldn't swop old needles with new seats or the other way. In the end i had to modify the flap on the floats to take account of the different angle on the new needles!!


AL

[paulmceleney]

alan they are fibre washers ,can not stop it so i will buy new washers and float valves

[Rich]

Swap the valve with the one from another carb and the fibre washer as well to prove it.

The fuel is coming from there isn't it?

With you saying they have stood on the shelf for a bit the 0-rings in the fuel rail dry out, shrinking and leaking until either replaced or expanding.