The Anatomy of a Carb Sync
How do you know which one to adjust?
The carburetor sync on a 2 stroke or 4 stroke ROTAX Engine is one of the most important functions to keep up with for the health of your engine.
Let’s take a look at performing a carb sync on a 912 series engine. The carb sync is nothing to be afraid of and with a few times at bat, performing this function will become fairly easy. First, why is it so important? The carb sync should be done anytime the carbs or throttle cables are removed or adjusted and at the 100 hour or Annual Condition Inspections. The reason for this is cables stretch, cable hysteresis (cable stickiness), pulley system wear, cables slip and because parts wear and end up with more tolerances. The carbs are almost always out of sync at each 100 hours or the Annual. If you did a carb sync back at the last inspection then they may not be out of sync much, but they will in most cases be out at least a bit. The sync instrument should also be used to set the idle sync if you change idle settings. Let’s start off with thinking of the engine as two engines, a left side and a right side. Two carbs controlling different sides of the engine. You don’t want one side trying to operate at 5000 rpm while the other side is trying to operate at 5100 rpm. These opposing rpms will cause excessive stress and wear on your engine over time and possible damage. You say there is a balance tube in between to help balance them out. The operative word in that sentence is “help”. The balance tube can correct and help with small differences between the two carbs, but it is not a cure all and it is there to help make the system run a little smoother than if there was no connection or correlation between the two carbs...
Related E-Learning Videos:
Bing 54 Carburetor Rebuild - 2 Stroke
Carburetor Needle Position Adjustment
Related Product Review Video:
