Fuel level - float height

[victor]

Hi

Still having problems with carbs weeping fuel from float bowl gasket.
I know what the float height should be set at but where should the fuel level be relative to the gasket? I have fitted  transparent side tubes and the level with the floats set at 21mm seems very close to the gasket level ..... where do people think it should be?

Thanks Greg

[looey]

Shouldn't leak from the float bowl gaskets whatever the level of the fuel in the carbs.

If the level gets too high, it should overflow into the brass tubes and out of the back/bottom of the float bowls

Even then, it should leak from the gaskets.

Have you fitted new gaskets ?.

[victor]

Yes new gaskets and new float valves. No sign of any damage to faces. Does not overflow just gradually seeps. Same on both carbs.

[victor]

Hi

I asked before but did not get an answer so will try again as this is driving me mad ..... What level should the fuel be at relative to the float bowl gasket, when I set to the recommended 21mm the fuel level appears to be above the gasket level and presumeably below the overflow level as it is not overflowing but my thinking is that this is too high? Would appreciate other opinions.

Thanks Greg

[looey]

In my experience the fuel level is normally "just" below the the gasket face but petrol creates a lot of vapour and with the fuel sloshing about in the float bowls, the gaskets will still leak/weap if they don't seal corectly.

I'm sure your problem is just getting those gaskets to seal

Dunno if this link works (if not just google carb float level clear tube) that gives you a good idea

www.google.co.uk/search?q=carb+float+level+clear+tube&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiGroHp5N7WAhXILFAKHTDrA8wQ_AUICigB&biw=1366&bih=662#imgrc=dtGJQ1uKHKe5vM:

[stusco]

I always thought it should be the same height as the gasket,
I bought dodgy carb kits once and the gaskets didn’t fit properly and they leaked so I fitted my 20 odd year old ones back in nd they sealed! Get proper gaskets

[victor]

Thanks for thoughts. Bought a second new set of gaskets and they were much worse than the first hence my frustration! As they are fibre I can not see them working when constantly wetted with fuel? Will try setting just below the gasket. Any gasket sealants that work with petrol?
Greg

[stusco]

Shouldn’t need sealant you will need in there often ,have you tried norbo or allens for genuine gaskets

[midlifecrisisrd]

No sealant on a float bowl gasket

If the gasket ain't sealing due to it being crap or damage on the faces.

We're they genuine gaskets

Doesn't matter where you set the float levels. When your leaning round corners the fuel will be on the gasket join anyway

When you do fit new gaskets I'd nip the screws up then leave overnight as the gaskets crush a bit.

Next morning you can always get a half turn on the screws

Steve

[Tobyjugs]

Did you replace the O-rings around the new needle valves?

[looey]

Oct 8, 2017 11:07:56 GMT 1 Tobyjugs said:

Did you replace the O-rings around the new needle valves?

I don't think he has any probs with float heights or carbs overflowing, just float bowl gaskets weeping ?.

[Tobyjugs]

Have you got any pictures for us of the carb and bowl faces to see and one of the gasket used. I have used Rob on here for float bowl gaskets and never had a leak with these.
His name on here is 4l04ever, pm him.

[TZ750D]

If the new gaskets don't seal they will leak when the bike is started up due to fuel sloshing around. I used some new gaskets out of a k and l kit on my Z1 (I wouldn't use any jets, needles etc out of those kits) and even nipping them up 3-4 times they still leaked. Only use genuine gaskets, and soak them overnight in fuel first. As others have said, don't use any sealant 

[steven]

...have the jointing faces or the carb been damaged by over zelous "tapping" with a screwdriver or something heavier when the float valves stick ?

As per the Haynes manual, the 21 mm measurement is taken from the carb body gasket face.
As you will see, there is a "notch" on the side of the carb body, where the float bowl mates with the carb.
I have never seen it written down anywhere, but the only reason I can think that this notch is here, is to use while setting/checking the float height using the clear pipe method, as the top of this notch, is in line with the gasket landing/mating face.
steven.

rdlccrazy.proboards.com/thread/20423/float-heights

[victor]

I am having problems getting the float height right but my original problem was weeping gaskets. I am pretty sure the fuel level is too high when set at 21mm though it is not coming out the overflow. I was unsure where the fuel level should be but the view seems to be just below the gasket but the view also seemed to be that it should not leak regardless of the fuel height? The float valves and O rings are new and do stop the fuel flow when operated manually with the bowls off. I think the discrepancy in heights might be because there is some wear where the float tang contacts the float. Ideally I suppose floats should be replaced as well but seem expensive if I can just compensate with the height and they are not he cause of the problem. I had not heard of soaking the gaskets overnight to get them to seal. I have sent pm to Rob.
Greg

[richclare]

Hi Greg,

I have exactly the same problem after my rebuild. The carb gaskets are new and seem to leak like a sieve! The old gaskets (I think were original) did a much better job of holding the fuel in. I am going to buy some replacements.

Rich

[richclare]

Just a question to add to this link.....

I have a similar problem with the float bowl gaskets. I've changed them once and they leak, actually it's more like seeping, leaving a film of fuel on the float bowl side. I think it's because they were cheap so I have ordered some new ones from Norbo. I wanted to know if anything has to be done before fitting them. I know someone said to soak them in fuel overnight before fitting? Any other tips would be appreciated.

Cheers

Rich

[earthman]

It's been many years since I've stripped carbs, never heard of soaking a new gasket in petrol before, what's the theory behind that then?

[richclare]

Oct 15, 2017 14:38:10 GMT 1 earthman said:

It's been many years since I've stripped carbs, never heard of soaking a new gasket in petrol before, what's the theory behind that then?

It was mentioned earlier in this thread.... I assume it helps to swell the gasket first?

Rich

[4l04ever]

You can rub a thin smear of grease onto the gaskets to make them less porous. Let us all know how you get on.

[richclare]

Oct 15, 2017 20:21:55 GMT 1 4l04ever said:

You can rub a thin smear of grease onto the gaskets to make them less porous. Let us all know how you get on.

Thanks for the tip. I will post the result - fingers crossed.

Rich

[philymon]

Set mine at 20 mm from base of float bowl to just as float was touching shut of valve, checked after reassembly using clear tube and found 5 mm difference between left and right, could be tension diff. In shut off valve but even higher than base of float bowl it didn't leak,

[richclare]

Received my carb repair kit from Norbo. The new gaskets are fitted and no leaks☺. I presume the old gaskets, which I bought from ebay, were poor quality. I did put a thin smear of grease on the gasket too, before fitting.

Rich