Help carbies flooding

[Chop089]

Hi all

I have a set of bs38 carbies on my 1976 xs650c and they keep flooding and fuel is running from the overflow and through the main jet air inlet, I have adjusted the floats to 25mm and I hav no idea why it's doin it and it's really Fukin annoyin! Excuse my French. All I can think of is maybe the floats are upside down

 

[TwoManyXS1Bs]

Hey, Chop089. Try a forum search on "q-tip", and have a look through all the thread titles that mention carb problems, leaks and overflows. Hope it helps...

 

[Chop089]

Thanx I'll have a look

 

[peanut]

Fuel is getting past your needle valves. The needle valve tips may be hardened and not sealing properly
Why not invest in a carb rebuild kit and replace the needle valve and seat assemblies .
https://www.mikesxs.net/product/48-7879.html

Check that both floats in each bowl are set at the correct height 24mm or whatever from the gasket face not the rim of the fuel bowl. Its important that both floats are equal height in each bowl so don't just measure one side of each float measure both.

Check that none of the floats are leaking on a seam etc . It might not need much of a float leak to effect operation of the needle valve. lastly make sure that the pivots on both floats are free and smooth and that there is no friction anywhere that might prevent the floats rising.

Lastly check that the tangs on each float is perpendicular to the needle valve when in the shut-off position ie hold the carb upside down. if the tang is crooked it will cause friction on the needle valve and may prevent shut-off

 

[XSLeo]

www.amckayltd.com/carbguide.pdf
I wouldn't buy a rebuild kit, the one peanut linked is not for your carb. Just buy new float valves. The kits come with most of the parts that won't work in your carbs.
Buy just the parts you need.
The Q-tip is a good tip. It polishes out all the crud in a used seat and polishes out any burrs in a new seat, just use finger power, don't put in in a drill to spin the Q-tip, this removes too much, too fast.
Leo

 

[peanut]

at that price surely it hardly matters leo
Both the gaskets and needle valve parts are needed ...just keep the parts you don't use for another carb clean .

I see that you didn't supply a link to anything

 

[chizler62]

Brass floats? I'd make sure there not cracked or leaking. Put in pail of water and make sure they float and don't take in water etc.
Check the needle itself making sure there isn't a small ring around the tip. A deep ring will not seal well at all.
Clean the needle valve seat with a q-tip as suggested.
When reassembling dab a bit of bearing grease on the needle itself.
Set float height. Lightly flipping carbs until the float tab takes the slack up.
Be certain the specs you're using are for the carbs your working on. Sounds silly but I keep seeing XS650's in my shop more and more with hacked parts from different years etc.

 

[Chop089]

Thanx guys for all your replys, they magically stopped leaking after I started the bike up, I think the vibration must have made it sit right. I had previously rebuilt the carbies using the mikesxs kit and it was shit, I got all the wrong parts and ended up getting all the right ones from geoffsxs site