TOPIC:

Hi, I have had this problem since first owning my bike:( !!!! over fuelling, air box full of gas and running into the engine !!. Not realising what the problem was until close inspection, Bad plug fouling ect ect. Recently I have removed the carbs, set up a stand on my workbench. With spirt level set up so perfect, gauge tubes fitted so a visible float level can be set up.
The problem is, when looking in the official workshop manual it only gives you a float gauge "Tube Type" measurement. Most bikes I have ever worked on always give you a FLOAT HIGHT. I Started when I first stripped down the bowls. just to get a starting line I put a 4mm drill bit under the tab of the float. Over night this was over fuelling on all 3 . Cut a long story very short. The tabs are now bent up to accommodate 6.5 mm drill bit fitting under the tab (this is a snug fit.)
Floats, I Tested them in glass jars with Gas, over a 3 week period, fully submerged and weighed them before and after, found no problem here.
Warning ! with the drill bit method, if you go up to 7 or 7.5 mm you will shut the valve off. But at 6.5mm This is the very first time I have seen the Carbs stable. I would like thoughts on this please. Happy new year to all you Guy's.

Your problem is petrol getting past a float valve seat (or seats) or the o ring on one or more of the BRASS float valve seats is letting fuel past.

Its not all about float heights.

Pete F
UK

All O rings brand new N.O.S parts, all tested without float valve and plugged. 100% no leak here.

You have another topic running at the same time talking about steel float needles and steel seats. As I understand it, the stock needle seats are brass and that's what's in my 1980 B2 so I'm at a loss as to why you have steel seats and wonder if they are physically the same size with the same seat faces so they can use the stock float needles.
Something's funky in Chinatown me thinks.

Hi Kawboy. Sorry but I jumped on to the other debate, as some of the problems looked to be the same. My Needle seats are all Brass ! my Topic was all about Tabs on the floats. Then getting a stable level inside the bowls "not easy and time consuming".
Also in the official workshop manual, lack of a measurement of where to start as a float height. As I've owned lot's of bikes over the last 40 years and never seen a bike without this measurement.
So I started the task to find a fuel level and tab measurment that was stable, without overflowing.