Topic: Carb questions, CB750K1-K6's

[Eydugstr]

Got a couple of questions....

1)  On the air/idle mixture screws, have noticed three different styles.  One had a hollowed out tip with a larger hole going through the side, another was solid but had a hole by the tip, and one that is solid.  Why three different styles?  Emission regs?

2) Are the aftermarket (black plastic) floats decent replacements?  I know that the aftermarket brass is generally frowned upon.

[ekpent]

Not sure on all the different air screw deals, have seen them also but put some black floats from later year carbs in one of my K1's with good results.  Brass would be OK also,especially nice new ones. I have had a couple of originals with issues/leaks.

[evanphi]

The screws with the holes in them will be more lean given the same number of turns.

FWIW, I have 7A carbs with solid screws... got the holy screws with a carb kit, tried them, and couldn't get them to adjust rich enough. Went back to solid screws, plenty of adjustment.

[Eydugstr]

The screws with the holes in them will be more lean given the same number of turns.

FWIW, I have 7A carbs with solid screws... got the holy screws with a carb kit, tried them, and couldn't get them to adjust rich enough. Went back to solid screws, plenty of adjustment.

Wound up with the same results - the only way I could get an idle low enough to easily find neutral while running was using the solid screws.

[ekpent]

Did you not try the large knurled idle adjustment knob on the top of the carb rack to lower or raise idle speed ??  If that does not function something is out of whack with the slide adjustments.

[Eydugstr]

Did you not try the large knurled idle adjustment knob on the top of the carb rack to lower or raise idle speed ??  If that does not function something is out of whack with the slide adjustments.

Yes.  Was able to balance out the slides with a set of vacuum gauges, but the bike wouldn't idle under 1700.  After re-reading HM's book section on carbs, he mentioned the solid screws helped lower the idle, and remembered having a set in my used stuff.

[harisuluv]

I think you should tell us the exact details of your setup, before going to another tangent.

What bike do you have, what mods, what year, what casting of carbs, what has been done to them, what are the carb settings, the air screws may be the least of your worries