If you were Registered and logged in, you could reply and use other advanced thread options
|
Posted by on August 5, 2007, 12:13 pm
So I have a problem here
My gl 1100 takes too long to drop the rpm for up shifting or generally
down to idle.
I have rebuilt the carburetor (cleaned and replaced all the rubber
parts and screens with new, I have oiled the diaphragms) the throttle
cable returns swiftly and is not the problem, the vacuum advance from
the back of the engine seems to work fine and no leaks detected on the
way to the carb.
Any thoughts? I am at a loss here!
|
|
Posted by Albrecht via MotorcycleKB.com on August 5, 2007, 12:49 pm
yarbel@hotmail.com wrote:
>Any thoughts? I am at a loss here!
Most owners are at a loss to how a CV (diaphragm) carburetor works. Your idle
fuel air mixture is too rich because the throttle butterflies are too far
open and
maybe somebody has tried to adjust the idle mixture screws without
understanding what they are doing.
http://www.bikebandit.com/partsbandit/showschematic.asp?dept_id=210652
Item #5 is the idle mixture screw. Turning it clockwise leans up the mixture,
and that's what you want to do, if you or any previous owner has tried to
adjust the
idle mixture screw without an understanding of how the idle mixture circuit
works.
The idle mixture circuit gets fuel through the idle jet and it gets idle air
through the pilot air jet which will be in the mouth of the carb or
underneath the diaphragm.
The idle gas and the pilot air mix, and then the idle circuit splits off.
Only about 1/4th of all the fuel air mixture goes to the idle outlet port
that is controlled by the
idle mixture screw underneath the carbs.
There are three OTHER outlet holes just underneath the bottom edge of the
throttle butterfly. They are called "transition ports". The purpose of the
transition ports is to feed the engine extra fuel air mixture as the engine
vacuum downstream of the butterfly drops off when the rider opens the
throttle.
Three quarters of all the gasoline your Old Wing needs while cruising down
the freeway comes through the transition ports.
If nobody has ever tried to adjust the idle mixture screw, the transition
ports will still cause problems, because the single fuel air outlet port and
passage gradually gets clogged with gum and varnish and somebody along the
line will turn the idle SPEED screw up, uncovering the transition ports.
Then, when somebody cleans out the carbs, they make the mistake of trying to
set the idle mixture by turning the idle mixture screws counterclockwise.
They think that the idle speed should increase the more they turn the screws.
Finally, they get the idle mixture so rich, the idle speed slows down, the
exhaust sounds becomes dull and thudding, and they have to turn the idle
speed screw up to increase the engine RPM and then the carb gets gasoline
from the
transition ports when the engine just doesn't need that much fuel.
The whole idea of adjusting the idle mixture is to get the engine to idle at
a slow speed by turning the idle SPEED screw down and covering up the
transition ports with the bottom edge of the butterfly. You cannot adjust the
idle mixture if the transition ports are uncovered.
--
Message posted via http://www.motorcyclekb.com
|
| Similar Threads | Posted | | 1996 vt 1100 honda shadow | July 1, 2008, 8:33 pm |
| 1992 CB250 Hesitates on slow acceleration | August 3, 2007, 12:57 pm |
| 1994 Honda Nighthawk Idle too High & Clutch Question | May 16, 2007, 9:41 am |
| 1980 CB750 F braking | October 8, 2007, 7:49 am |
| Re: There's no fun like clutch fun! 1980 CB750F | October 20, 2007, 1:59 pm |
| Re: There's no fun like clutch fun! 1980 CB750F | October 23, 2007, 2:25 am |
| Re: There's no fun like clutch fun! 1980 CB750F | October 21, 2007, 8:24 am |
| Re: There's no fun like clutch fun! 1980 CB750F | October 21, 2007, 9:01 am |
| GL 1100 Radio | July 25, 2007, 8:22 am |
| Re: Carberators kawasaki 1100 A3 | April 10, 2007, 1:57 am |
|
|
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap