carb overflows

[jayel]

it really bugs me that these carbs don't have overflow tubes, any one with a stack of loose carbs willing to take a look and see if it would be possible to drill the bowls and mount a overflow? is there space to run a tube up past the floats like on the old BS38 carbs... brass tubing from a hobby shop could be epoxied or soldered in and would sure save a lot of air filters and oil from fuel contamination

[BA80]

unnecessary if things are working correctly.

[jayel]

unnecessary if things are working correctly.

same could be said for reserve parachutes or more than one bullet but back up systems are nice to have

[BA80]

My point is, don't FUBAR a set of carbs that is becoming more and more scarce just because of operator error.

You can get them right, we all did.

[crazy steve]

The type of 'overflow' protection you're looking for can't be had because of the carb design. Where the fuel get into the oil/airbox is from the emulsion tube; the only way to prevent that is to install a 'vent' that's lower than that is, and you'd have constant flow out of the vent from the bike's motion...

[TADracer]

Like a plane crash

Alot of times fuel leaking from the carbs is kind of like a plane crash....several small things happening at the same time to cause the event. If all is adjusted well and in good repair leaking should not happen and the vent probably has nothing to do with it since it is a gravity fed fuel system.

Here are a few ideas. Check your bowl level is not too high. If you have float valves without the Viton tip in your model then any small particle through the fuel lines can 'hang' the valve open slightly. Is there fine debris in the bottom of your bowls? If yes then you need filters. These old machines really need them anyway. Do your floats operate freely and not hang up on the bowl gasket? Do your floats 'float' correctly. I know it sounds silly but some have been known to sink a bit. Do you turn your fuel petcocks off when not running? Are your petcocks in top shape? Is the inside of your tank squeeky clean?

These and a host of other things can cause that nagging drip drip drip. They are all small things to check and correct and usually it is a combination of more than one causing the carbs to drip.

[jayel]

first off I am not having a carb problem (at this time) and yes when everything works as it should it's all peaches and cream ,
which is why a lot of people remove the octy and other mods.
as to the overflow tubes maybe a solution in search of a problem but seems to work on other carb models,
tube tip higher than bowl fill level, sitting up into ceiling of float bowl chamber ... think you're over estimating slosh factor unless you're doing 1/4 mile starts/stoppies
not my carb but somewhere in red circled areas would be above fuel level but drain before fuel leak reached carb throat to flow into airbox or engine it's just getting them over close to the jet towers to clear the floats

[James England]

I personally wouldn't start drilling carbs to fit overflows. As most people have said, it's far better to get the carbs working perfectly and keep them that way. It's not difficult. OK, so you fit an overflow and one day it starts piddling fuel out... then what? Carb strip and get it all working properly.... just like if there were no overflows and fuel piddled out of the airbox.

I really don't see the point of it. Unlike other mods, which give a constant improvement in some way from the minute of modification, this overflow thing doesn't do anything until the fateful day when due to something like a float needle mishap or bit of dirt, they then start allowing fuel to come out... thus indicating that the carbs need stripping.

Backup systems are all very well in their way and for certain things but this isn't a backup system. It's not backing anything up. If the carbs start malfunctioning, this proposed mod. doesn't back anything up. It just lets you know, in a different way, that there's a problem in the carbs.