fuel leak from top of bowl

The carb bowl gaskets are new from a K&L repair kit bought off Ebay.  I am seeing seepage from at least 2 of the carbs right where the bowl meets the top.  It does appear to be coming from the left side of the bowls as you face forward.  With the bike on the kick stand the gas would probably be fuller on that side.   Any idea why these would be leaking?  I have no fuel going through the overflow tubes so the floats and seats seem to be doing their job.  The seat and needle were also replaced.

 

While I've never personally seen it, some members report warpage of either the carb body or the bowl.  

How thick are those bowl gaskets?  Some are thicker than others.  

It's a common occurrence on older carb bodies unfortunately, i see it all the time. What's actually happening is fuel is weeping out around the centerline to venturi mating bowl to carb casting surfaces. Over time the carb casting "bows", outer sides where the (4) screws tighten pull the casting material down. Because flat surfaces of casting and bowl can't compress a flat gasket and the only clamping is on the outer edges bowing begins. I've seen persons think it's the bowl that is warped but that's Never the case, always the carb casting. And person's rarely address this common issue because when setting float/fuel levels on the "bench" you won't see the weeping till carbs are exposed to the Real World of fuel sloshing when riding or as you have found, on the side stand where fuel is present at the mating surfaces. Unorthodox i know but i oring the bowls. It's a tricky ordeal but it works. Nessism  Loves the concept too, NOT ha but i've been doing it for over 15yrs on all sorts of engines without a single failure. Example shown, not your type bowl but theory/application  remains the same 

The shape and precision of that o-ring is pretty amazing.  How does one even attempt to make this and keep the shape that's needed?

LTDflyer1000 wrote:

The shape and precision of that o-ring is pretty amazing.  How does one even attempt to make this and keep the shape that's needed?

Superglue.  

@asphalt900 Do you know the thickness of that o-ring material?   My #4 is leaking pretty bad and I need to try something.  Looking to buy some kind of kit off Amazon/E-Bay.   Would it also be possible to just cut a new gasket like the one that's there but just thicker. Maybe using some kind of Nitrile Bonded Cork

I made gaskets out of 1.5mm Viton sheet



 

Great job as Always Wookie, making your own brew! Unfortunately the "pumper" style VM's are waay more complicated then the BS series. BS's rarely had leaking issues though because the carb castings were soo much more beefy. As Ness mentioned, just superglue attached LTD. Nothing fancy but surface has to be nice and clean for proper adhesion. So strong the bond is you can hook onto the rubber and dangle a pound or more only to rip the rubber, not pulling it off. Anyway have a look thru the photos, might guide you in the direction if you want to try it. I've been completing a couple similar sets at the moment so perfect timing for photos. One is Your 1980 LTD, other 1980 ST or often used on the Z1R. While they outwardly look similar, many variations, one being the Idle Adjustment Knob location. You will note i use a 2mm cord stock for bowl but an ID 3mm X 2.5mm oring for pump nozzles. Original oring if purchased is thinner.         This extra .5mm assures sealing off the pump pressure to nozzles when castings are bowed as mentioned earlier. Visual fuel delivery can still take place at each nozzle but bleeding off back into bowl or outside if this isn't addressed. Just keeps things tidy and fuel tight.