A Guide to Marauder Carburetor Synchronization
Thanks to Bob Arnold #7947 for this article
What is a carburetor Sync?
On engines that have two or more carburetors it is necessary for all carbs
to do the same amount of work, otherwise one cylinder does the majority of
the work and you end up with a rough running engine.
In its simplest form, Synchronizing the carburetors is adjusting the
butterflies in all of the carbs to open an close at the same rate, thereby
ensuring that all cylinders are doing there share of work.
What is adjusted to sync the carburetors?
- Engine RPM
- Air/fuel mix to 1-3/4 turns out
- Carb sync adjustment cable
What tools are needed to sync the carburetors on a Suzuki Marauder?
- Two vacuum gauges with restrictors
- One 8 and 10 mm open end wrench
- One small flat blade screw driver
Suzuki Marauder carburetor synchronization instructions
- Make sure the enrichment valve operates freely
- Hook up your tachometer
- Hook up your vacuum gauges with restrictors to front and rear
- Set air/fuel mix screws at 1-3/4 turns out (California
- Remove the throttle cables at the handlebar
- Disconnect the throttle cable at the splitter on the left hand
side of the front air cleaner
- Adjust both pull cables to be the same length
- Start engine and warm up
- Set the idle to 800 RPM
- Adjust the rear carburetor sync cable for a close vacuum
reading between both gauges (within 1 inch of vacuum)
(DO NOT ADJUST THE FRONT SYNC CABLE)
(Note: When facing the rear carb, turning the rear adjuster
clockwise will increase the vacuum on the rear carb and decrease
the vacuum on the front)
Re-check the idle RPM and adjust to 800 RPM if necessary
(You will need to adjust the RPM several times while you sync the
- Remove vacuum gauges and install sync gauge.
- Adjust the rear carburetor sync cable for a balance between front and rear carbs.
Note: Little adjustment should be required at this point. If your vacuum reading was within 1 inch of each other, then this step may not be required and is only for a visual verification of sync
- Remove sync gauge and install vacuum gauges on both carbs
- Check and adjust the idle speed to 800 RPM, then adjust the
air/fuel mix screws on both carbs for the highest balanced vacuumi
reading (You will only need to adjust the idle/air screw about i
1/8-1/4 turn) Re-check the idle RPM and adjust if necessary
- Readjust if necessary the throttle pull cables to be the same
- Reconnect the throttle pull cables that were disconnected in
- Re-assemble the throttle cables at the handlebar
- Adjust the pull and return throttle cables at the handlebar
- Increase engine speed to 2500 rpm
- Check and re-sync if necessary the rear sync adjuster cable for balance between front and rear carbs
- Put the bike back together and take it for a test run.