Monoblck carb weeping fuel

[Barnsey]

Dear All,

   My monoblock is weeping fuel around the the end cover, despite having a new gasket.  I reckon I will order a new set of screws as the ones on there are mashed up, but would anyone recommend using a sealant on the gasket?  If so what brand to go for? 

     BR,   Ian

[idie]

The chances are that the cover is distorted. Unusual for the carb body to distort you can check carb by rubbing it on some glass with some grinding paste.plenty of covers on ebay.

[Barnsey]

Maybe you are right!   

I'll take a look on Ebay.

[iansoady]

Some (aftermarket) gaskets are very thin. The proper Amal one is a thick one which seals better.

[V500]

Yep, some gaskets are just thin paper while the proper jobs are the thick red or green coloured ones.

[Barnsey]

Okay! I've ordered a new cover, screws and new gaskets.  If the gaskets look to be on the thin side I can put two together.  This looks to be the sledge hammer approach. If that doesn't work I will have to try Hylomar. 

[iansoady]

Wellseal works better in my experience. But you shouldn't need anything with the correct gasket.

[Dean Southall]

I have never had to use a sealant.

[DAVE BRADY]

Hi,

I have never used sealant either.  Get a gasket from Amal. The proper ones are branded.

Dave.

[Barnsey]

I see what you mean about the difference between original and non-original gaskets.  I thought that mine came from Amal as a part of the servicing kit but I will check.   It was a while ago. 

[MadPete]

I personally would not recommend a jointing compound on the carb bowl as it can make disassembly and cleaning a bit of a chore. Real petrol resistant sealers stick like the proverbial and can be difficult to remove.

If the mating surface of the carb bowl and the carb body are reasonably good then the correct (thicker) gasket will do the job very well and is usually to be preferred.

If the mating surfaces are very compromised then replacement is the only real solution. Using a grinding plate/paste to reface the carb bowl is possible but remember to check the inlet needle level adjustment.

[Stubaker58]

RR has a section in the unit singles book on this issue. Very often it's the lid which is distorted and needs bending back. RR gives dimensions for a jig to do the job.
Regards.

[ducati2242]

cant remember which bike i was working on at the time but the amal monobloc was always leaking at the float chamber cover . It turned out the float spindle bush was too long and stopping the cover fully tightening . I even faced off the cover in the lathe as i thought it must have been warped but it still leaked until i realised that the bush was the wrong one . It could also be the float axel is touching the cover and holding it back from fully tightening .

[Barnsey]

Now that is an interesting thought!  I will check thanks!

  It looks like this might have been an issue for a long time as the paint had stripped from the chain guard underneath.  I thought that I had fixed any leaks in rebuilding the carb, so I treated the chainguard to a fresh coat of paint, only to have the new lacquer turn to marmalade!

[MadPete]

I presume the leak has been confirmed from the gasket seal area. If not, I wondered if it might be an overflowing carb via the tickler button? Rare but possible I suppose...