Topic: how the heck does this work?

[possum2082]

new member bringing a 76 550k back to life.  i was cleaning out the carbs looking for a leak, assuming some gunk in the float valve seat when i noticed that the float valves have little spring pins on the end that you can push in.  i'm used to mikuni carbs that have a float valve that attaches directly to the float.  why is there that springy thing on the end of the float valve?  why can't it be solid?  i just like to know these things.  thanks.

[333]

I have noticed 2 kinds of valves, one that has a rubber cone tip, and the other that has a metal cone tip.  The metal ones(which last longer) rely on that springy thing to seal.  The idea(I'm guessing) is to adjust the level high enough to compress that spring, and attain a good (metal to metal) seal.  The rubber ones don't need that kind of pressure.

[TwoTired]

If you stick a taper cone into a hole hard enough, it wedges into place.  The spring pins limit pressure on the valve seat/valve cone interface.  There is also vibration so consider.  Just as sand paper works faster with increased pressure, so would any wearing surface subject to increased pressure.  As the fuel sloshes about in the bowl, the spring pins absorb the varying pressure the float would otherwise exert directly on the valve seat/cone.

Or, some relative in the Honda family manufactured tiny springs.

Cheers,

[possum2082]

man, you guys are awesome.
thanks

[TwoTired]

Interesting note.
I just serviced my 77 CB750F PD carbs today.  Stock, was parked in 1985.  Anyway, float valve needles were rubber tipped AND they had the spring pins on the opposite end.

Cheers,