Leaking carbs

[Monkey man]

Hi guys

Can anyone help or give suggestions why my carbs leak

i replaced the jets and gaskets on my gt 750j and since doing so the carbs leak . It appears all 3 leak from the float bowls and seem to do do more so when the bike is on the side stand rather than the centre stand . After much investigation and taking the carbs off and back on numerous times I put back in the old fuel jets and also made sure the float bowls were securely tightened down. At first it seemed all was well but after having been out for a ride and parking it up in the garage on it side stand the problem has returned and petrol Is leaking out again - it doesn’t look like it’s from the overflow and I’m convinced it’s the gaskets . Float bowl height was checked and is ok so what is the problem/ They didn’t leak before i replaced the jets etc and I only did so after fitting a replacement petrol fuel cock .

Any advice would be appreciated

And

[Alan H]

Common cause would be the float needle valves aren't sealing when the floats should lift and press on the spring loaded valves. It can also be that the fuel tap is leaking with the engine off, especially if the bike is left on the side stand as the fuel will overfill the left carb and then overflow it. Make sure it's on 'on' or 'res' and not left on 'pri' or prime.
Have a look here - https://alpha-sports.com/suzuki_parts.htm - and select year, model, carburettors to see an exploded diagram of the carbs. Make sure item 20 is fitted above all the needle valves as it will alter the float heights and can also cause similar problems to yours.

[Monkey man]

Hi Alan thanks for the response - item 20 appears to be the floats on one of the diagrams and needle jet on another - do you mean the float needle assembly ?

I replaced the latter with new and reverted back to the old ones when a problem developed but the problem persists .

The fuel tap is a new replacement and yes the tap is switched to on or reserve and not prime

I was thinking of bending the tangs on the floats to let less fuel in but don’t know if this would solve it

[Alan H]

Hi Alan thanks for the response - item 20 appears to be the floats on one of the diagrams and needle jet on another - do you mean the float needle assembly ?
Item 20 is the fibre washer above the needle jet .

I replaced the latter with new and reverted back to the old ones when a problem developed but the problem persists .

The fuel tap is a new replacement and yes the tap is switched to on or reserve and not prime

I was thinking of bending the tangs on the floats to let less fuel in but don’t know if this would solve it
That will affect the fuel level. But if you drop it a couple of millimetres, it should be ok

Do the carbs still leak if the bike is on the centre stand, and does petrol leak from the tap if you pull the pipe to the carbs off? I got a new tap and it still leaked, so had to refurb the old one eventually.

[Bobf]

Float bowls can become distorted when being removed and replaced often, leading to a poor seal with the carb body. I would suggest checking how flat the bowl is by lying it on a decent flat surface or using a steel rule to look for gaps between the bowl's mating surface and the flat surface.

[karl pa]

Float bowls can become distorted when being removed and replaced often, leading to a poor seal with the carb body. I would suggest checking how flat the bowl is by lying it on a decent flat surface or using a steel rule to look for gaps between the bowl's mating surface and the flat surface.

I agree, if you lay sand paper or emery cloth on a flat service and slide the float bowl across it, you will probably find the 4 corners at the screw holes to be a high point. You can work everything flat, but it can take a bit of sanding.
If you over tighten the screws it will distort the bowl more. (I know this from experience.)