Fuel leak from Carb breather tube

[Mowjoe]

Only noticed this slight fuel leak from No2 carb breather pipe due to it resting on the swinging arm pivot but what does this indicate is happening in the carb? The other breather and the float bowl overflow pipes are all dry.
Advice appreciated

[Compo1955]

If fuel is coming from the float chamber overflow pipe, this indicates that the fuel level in that carb is becoming too high.
It may be that the needle valve is being held off its seat by debris or the seal between the valve and seat isn`t as good as it should be.
If it is something between the jet/seat, it might clear next time you run the motor ( it you are lucky), if not you will have to remove the float chamber and have a look.....

[pertonpc]

Hi,
The tubes that go from bottom of carb float bowls are OVERFLOW not BREATHER.

Breather tube is a seperate one routed upwards ending near air box.

Need to check fuel level in float bowls - if the leaky one is higher than rest that will need adjusting.

Like compo says it is common to get a little fuel weeping sometimes.

If you have a gravity fuel tap (not vacuum) try turning off a few minutes before you stop the engine.

If persists you gotta drop the float bowl and clean or replace the float valve if it is worn.

From Mark

[ZedHead]

As compo said. Try tapping the float chamber bottom with a screwdiver handle, it might clear it. What is the tank like inside?

[snotie1965]

As compo said. Try tapping the float chamber bottom with a screwdiver handle, it might clear it. What is the tank like inside?

The same happened to my gpz11 , running lawson carbs ,i tapped it all around the float chamber with carbs in place, (not to hard) and it stopped leaking ! that was two months 300 miles ago , so it is worth a try ,you may be lucky ?

[Mowjoe]

I have no leakage from the float bowl overflows. The leak is from no2 carb breather tube which exits from the carb in the area of the throttle valve. Any ideas?

[Mowjoe]

If fuel is coming from the float chamber overflow pipe, this indicates that the fuel level in that carb is becoming too high.
It may be that the needle valve is being held off its seat by debris or the seal between the valve and seat isn`t as good as it should be.
If it is something between the jet/seat, it might clear next time you run the motor ( it you are lucky), if not you will have to remove the float chamber and have a look.....

All 4 float chamber pipes are dry.

[Mowjoe]

Hi,
The tubes that go from bottom of carb float bowls are OVERFLOW not BREATHER.

Breather tube is a seperate one routed upwards ending near air box.

Need to check fuel level in float bowls - if the leaky one is higher than rest that will need adjusting.

Like compo says it is common to get a little fuel weeping sometimes.

If you have a gravity fuel tap (not vacuum) try turning off a few minutes before you stop the engine.

If persists you gotta drop the float bowl and clean or replace the float valve if it is worn.

From Mark

It's not coming out of the float chamber overflow pipe but the breather on no 2 carb.

[z1bman]

in that case your fuel overflow pipe must be blocked if fuel is going that far up the carb body. have you looked in the air box? its probably full of fuel

[Mowjoe]

in that case your fuel overflow pipe must be blocked if fuel is going that far up the carb body. have you looked in the air box? its probably full of fuel

That might explain sooty plug on no2 and rough running when hot? Will have a look when I get home. Cheers Bud!

[pertonpc]

Hi Mate
If it is a carb breather pipe I don't think it should be routed to end at the swing arm pivot as you describe.
All breathers on early kwak carbs I seen are only about 20-30cm length and end up near the upper airbox area.

Also I think the breather by No. 2 serves carb 1 + 2 - should be another on tother side to serve 3 + 4. So the source could be 1 or 2 carb now.

Your pipe sounds too long or routed wrong - which might be part of the problem also.

[Mowjoe]

Hi Mate
If it is a carb breather pipe I don't think it should be routed to end at the swing arm pivot as you describe.
All breathers on early kwak carbs I seen are only about 20-30cm length and end up near the upper airbox area.

Also I think the breather by No. 2 serves carb 1 + 2 - should be another on tother side to serve 3 + 4. So the source could be 1 or 2 carb now.

Your pipe sounds too long or routed wrong - which might be part of the problem also.

Interesting that. I think the previous owner fitted new rubber pipes and has terminated all 6 around the swing arm area and just that one from carb 2 (and 1 as you rightly point out) was misplaced to be resting in the pivot dribbling fuel. Will investigate later. thanks a lot. MJ

[Mowjoe]

Should the 2 breather pipes go inside the airbox through holes somewhere?

[pertonpc]

Is it 900 A4 you have ??
If so I think I have seen the 2 breathers from carbs routed up through the frame baffle plate at rear of tank tube on frame and held on to clips on top of standard airbox. Will try and find a pic - try this one


http://www.ebay.co.uk/itm/Z900-kz900-Ai ... 7675.l2557

Sure an A4 owner will be able to confirm in a bit on here.

[Mowjoe]

Yes an A4 with VM26SS carbs. Can't get on ebay at work! or Fb! Thanks a lot pertonpc