On Wed, 08 Aug 2018 13:49:21 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
So .. I'm tending towards the thought that the floats have become
distorted somehow and are sticking on the inside of the carb body /
float bowl (when floating in fuel anyway) but I'm not sure how I would
check that.

Dunno these carbs, but with SUs you'd tend to replace the valve and seat
complete - it just screwed in.

Yeah, same on many bikes Dave, just not this one.

Does the valve and seat look OK under a magnifying glass?

I've not looked by daughter has (with her good eyes) but I should be
able to get in there with an endoscope.

If not, and the
seat is part of the carb body, I'd be inclined to lap the valve to it.

Except, these bike valves are often rubber tipped and so you couldn't
really use the valve itself to do any lapping.

Other thing is not enough lift from the float, or it sticking. But you
seem to have covered this.

Well, sort of. I am wondering if the float upside down in air is the
same (jet-sealing) effect as the right way up in petrol (buoyancy V
mass etc).

I assume you can't just by new ones?

No, you probably can but I'd hate to think how much. The throttle
slide diaphragms on this model are ~£100 each. ;-(

One thing I have learned since posting is that you can put a small
clear hose on the bowl drain nipple and run it up beside the carb.
Then you crack the drain screw(s) open, apply fuel then you can see
what the fuel level is in the carb bowl(s). ;-)

And that's fine of course, *if* it doesn't flood straight away! ;-(

Cheers, T i m