Float levels not wanting to set

I haven't been around here very much in recent times, and I have mostly divested myself of the XJ collection.

I am now down to two Yamaha four-cylinders: an FJ1200 and an FJ600, which is the reason for this thread.

Looking at the history of my posts here, I've been fighting carbs forever. Specifically, floats and fuel levels. Sure, it's as simple as a tiny toilet tank, but the whole thing with the guesswork in adjustments and the 20 million times you need to remove and reinstall the bowls... Ugh. At least fuel injection either works, or doesn't, none of this mysterious crap.

Anyways. The current problem, as I mentioned, is an FJ(XJ)600, pre-Diversion.

The carburetors have been rebuilt by Hogfiddles. They actually run, but they leak.

Needles and seats have been originally replaced with aftermarket sets. After being unable to set levels, I replaced the needles with OEM. Now, I seem to have succeeded on carbs 1 and 2, but still failing on 3 and 4.

If I take off the bowl and rubber-band the float upwards, nothing leaks anywhere. So, this is not an O-ring issue. Also, the needle seals.

When I tried to set levels, first, I got fountains out of the carb throat. I finally decided float itself may be a problem and got new floats.

Now, with new float, level is about 3mm above the edge of the bowl, and adjusting the float doesn't seem to change it any. I don't really want to keep bending the tab, it already looks not quite right.

What else can this be? I am out of ideas.

Maybe it's demonically possessed, and I should run some holy water through it?

 

you would have to ask him but I think dave only sets float height not wet set IIRC from another thread.

problem with mikuni carbs is the floats tend to stick when first filling.

there is a second tand that sets against the post which can be used to restrict float drop.
I have asked about this but have been told it is not to be adjusted so I can not really say to do that.

on off with the fuel tap a few times untill bowls fill while rapping them to keep floats from sticking. partially prefill bowls before putting on carbs.

best way is do individual carbs before assembling rack

 

Having a glass bowl to see what it going on inside would be nice.

I am doing this one at a time - if you tie floats up, that lets you work with just one.

The weirdest thing is, I never had this problem with Mikunis on the big FJ. Or, for that matter on the 550. It's something about this specific rack that's off.

 

maybe the float hindge is too tight on the pin through osts

 

I know you are an experienced mechanic but just to ask, which way are you bending the tang? Moving the tang in the direction of closer to the carb body should lower fuel levels and increase the measurement distance from the carb body. Are you measuring float height as a sanity check to be sure when you move the tang you have actually moved the floats?

 

I did think of that. I am doing this on a stand, with carbs mounted right side up, so there is no question which way float moves. And I did check to make sure.

At this point I am thinking the float is hanging up somehow, but I can't figure out how.

 

I don't have any advice other than to say I experienced the same frustration with my FZ600, same basic carb BS30 vs BS32.
I had one stubborn carb which would not seal. I dismantled it several times even resorted to replacing the float itself like you.
I continued draining the bowl, each time refilling accompanied with tapping the carb with a small hammer.
Eventually I got it.

 

you could try a dab of rubbing compound on the needle then spin it in the seat to lap them together.
look at the tang where it touches the needle for roughness that might not let them slide easy