Subject: Synchronizing/Setting Carbs
Author: Keith Ruff
Date: Mar 31, 2003, 5:38 AM
Post ID: 1712447083
Was searching through the archives of the loop board for carb stix info
and found some info Pat Hayes wrote back in DEC 2000. I am finally
ready to give this a shot after years of having carb stix sit on the
shelf. Was reading the directions that came with the stix and think I
have it figured out but wanted to get expert advise. I figured I would
go back to basics by the book and start by turning in the idle screws
(the ones without the springs) in all the way, then out 1 1/2 turns for
left carb and 1 3/4 out for the right (per the manual). Then I would
pull one wire and count 4-5 pulses on each side and adjust the screws
with springs on each side independently to achieve this. Once this is
set, I will follow the carb stix instructions which are:
1. Hook up vacuum hoses, start bike, adjust idle screws (screws without
springs) until the mercury levels are equal.
2. Rev bike to 3000 RPM's and assure levels are equal. If not, adjust
each side until they are (adjust screws with springs).
3. Once this is set, readjust carbs to set idle to 1000 RPM's.
Question, do they mean the screws without springs or with springs when
they say "readjust carbs to set idle to 1000 RPM's"? What do you think
of this process? Looking for carb setting/synchronizing 101 here. Andy
Hill had the bike apart and has adjusted the linkage/cables, now it's
just a matter of assuring the carbs are set correctly.
Here is a piece of what Pat Hayes wrote back in DEC 2000:
First, when the slides are at the bottom and resting on the idle
needles, are the two intake sides drawing vacuum the same? If not,
adjust the big screws. Please be sure to blip the throttle with each
minor adjustment. You DON'T want to just turn in the screw and have it
lift the slide. The load forces are too great and you risk bending the
needle and gouging out the slide. Just crack open the throttle a tad
and turn the screw a tad. Now , after adjusting for equal idle vacuum,
just begin to barely crack open the throttles. The carb stix will
clearly show which is opening first because one column will drop before
the other as that side opens and its vacuum deteriorates. Adjust the
cables so that both columns begin to drop (the slides lift off the idle
needles) at exactly the same time. This is where it is important. Low
rpm, no speed, you're just pulling away from a stop. Imbalance at this
point will be the MOST obvious and have the MOST detrimental effect on
the drivability of your engine and longevity of your driveline parts.
Imbalances at 3/4 throttle, doing 80 mph will be infinitessimal in
relation to the effect of imbalance at the "crack open" point. So,
since the entire linkage is imperfect, do your balance at the most
effective place and forget everything else.
Greatly Appreciate any advise.
Keith Ruff
71 Police Ambassador - NJ