Fuel level in Monoblck

[Barnsey]

Shut off needle in the carburettor? 

Sorry. Not familiar with this terminology, but, if you mean the main needle in the carb, then yes I have, and the idle jet too.

[scifi]

I think he means the float needle/plunger.   They used to be triangular brass, about 16mm long, which you could clean up the taper with something abrasive.   Nowadays they are Viton tipped, and maybe only renewable, if they are leaking.

[Steve.S]

The brass tap is usually used on much earlier bikes. I find they seize up after a short period of time and start leaking. Attempts to lap in the tapers are usually only a short term fix.
I can recommend the Wassell 73084 tap. Although rather expensive and flimsy, they don't leak or seize up.
Being of overseas manufacture, they have a metric sized hexagon, which is rather annoying, but the threads are BSP. It means that you will have to carry an open ended metric spanner in your tool roll, should you ever feel the need to remove the tap at the roadside. If you are a bodger, I suppose you could use molegrips.
Make sure you get either 1/8 or 1/4 BSP to fit your tank.

[Barnsey]

Ahhhh!  Okay, I understand now.  Yes, I replaced the 'needle' itself, but I don't think the kit had a replacement seat. 

The PVC tubing and the acrylic sheet has just arrived, so I can try some more diagnostics next weekend.   

[Mike40M]

I don't think the level of petrol in any float chamber makes a jot of difference to the richness of the mixture.  The reason for this is that it would take a column of petrol 46 feet high to make 1 bar (1 atmosphere.)  so a change of height in the float chamber of a few mm does not change the pressure on the jet very much.
You can see this in practice if you shut your fuel valve off at the end of a run, the bike does not change it's tickover until the fuel is exhausted.
So unless your float valve is malfuctioning, the level is not important, just as long as it is not overflowing or not flowing at all.

On my Manx Norton which has a separate float chamber, an adjustment up or down 1 mm of the float chamber makes a huge difference.

[yosemite]

Is the carb an original or is it a modern one from burlen. On burlen carbs the float needle seat requires a fibre washer below it while on the original carbs no washer should be fitted below the needle seat.
This in my experience causes overflowing if a reproduction seat is used on an original carb

[idie]

Yes the needle especially can get a wear ridge on the tip.

[idie]

Yes the needle can get a wear ridge on the tip.

[Dan_B33]

Double check if your pilot jet is fully in.
When I had too rich mixture (smoking black) and problem was not in float level. I had stuck pilot jet in the cap. It was never fully in. Replaced. All ok now