Real Honda 5.5 Carb Question?

D

DSLDAW

New Member
#1
#1
Have a KEI HIN carb on the Honda 5.5. Just wondering about the air/fuel
adjustment screw. It only has one main adjustment screw besides the
plastic idle speed screw. What does this adjustment do,since it only has
less than a quarter turn of adjustment? The spring behind the flathead,seems
to keep any adjustment moving back to the same basic setting everytime,so
I'm stumped. It is a needle valve that goes into the carb,just behind the
throttle butterfly about half way up the opening,horizontally. I took the carb
off to clean it and didn't see any other adjustments at all. Anyone familiar
with these carbs,please help me understand what the heck this single screw
adjusts? I'm by no means,a carb guy at all,obviously. Thanks.:confused:
 
N

Nrracing

#2
#2
It is an idle mixture screw that will will adjust the idle mixture (less that 10% throttle opening) provided the cap is removed. The cap can be removed by heating (with a small torch) and then pulling off with pliers.


Russell
NR-Racing.com
 
D

DSLDAW

New Member
#3
#3
Nrracing said:
It is an idle mixture screw that will will adjust the idle mixture (less that 10% throttle opening) provided the cap is removed. The cap can be removed by heating (with a small torch) and then pulling off with pliers.


Russell
NR-Racing.com
Click to expand...
Thanks for the response. I read the article about the idle mixture screw
in the clone website from this forumn. I think it's the one your talking
about,but the cap was not on the screw when I got the engine. It is
the only adjustment besides the plastic hex shaped idle screw,that
contacts the throttle knob where the linkage attatches,to adjust the
regular idle speed. The needle valve is located just behind the throttle
butterfly,right before the carb meets the block insulator.Shouldn't there
be a main fuel mixture screw,or is that it on this carb? I did notice a
brass screw,deep inside the vertical shaft that holds the float bowl cover
on,but it wouldn't turn at all,so I just left it,so I didn't break it and trash
the carb. That shaft goes all the way into the bottom of the center of the
carb,between the choke and throttle butterflys,so it must be the main
jet,I'm assuming?
 
ATKRIDER

ATKRIDER

New Member
#8
#8
The screw you are looking at that you can only turn a little is the idle mixture screw. The plastic screw is the idle SPEED screw. The main jet is removable and is in the center of the carb in bottom-it is a fixed size jet. I have drilled the main jet before but trust me a millascoch is a lot. Sometimes a torch tip cleaner can be used to kind of "file" if you need to richen mixture up just a fuzz. The oe honda carb is not by any means a motorsport friendly carb.
 
D

DSLDAW

New Member
#9
#9
ATKRIDER said:
The screw you are looking at that you can only turn a little is the idle mixture screw. The plastic screw is the idle SPEED screw. The main jet is removable and is in the center of the carb in bottom-it is a fixed size jet. I have drilled the main jet before but trust me a millascoch is a lot. Sometimes a torch tip cleaner can be used to kind of "file" if you need to richen mixture up just a fuzz. The oe honda carb is not by any means a motorsport friendly carb.
Click to expand...
Thanks. I get it now. The main jet just wouldn't budge. It does have a
tiny hole through the center of the brass flathead,where gas flows to
the carb,through the jet in there,I guess. A tiny drill bit would be kinda
tough to do,esp. if it broke inside while reaming it out. I'll try just opening
and cleaning it out with a torch tip cleaner. Good idea. Thanks.It seems
like it's running rich,already,so I'll just clean her out and plan on a new,bigger
carb in the future.
 
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