Synchronizer down-draft carburetors
If there are side mounted carburetors on the engine then they must be synchronized, this means that the adjustment of the carburetors both left and right must be exactly the same, for this job you need a synchronizer.
While running the synchronizer is placed on the carburetor and the vacuum that is generated is measured.This must be the same on both the left and the right. If this is not the case, you have to adjust the carburetors so both carburetors have the same value.There are two synchronizers available, a universal model which is suitable for both downdaft and crossflow carburetors (our air cooled engines do only use downdraft carburetors) and can only be used with carburetors with a flat top. In addition to this universal model there is also a professional version available, this can only be used for downdraft carburetors and is pressed in the carburetor instead of pplaced on top of the carburetor.
If your carburetor is equipped with very protruding parts, such as studs for mounting the air filter, then the universal model cannot be placed without inserting a piece of hose to remedy this. The professional synchronizer has a limited possibility for this, the rubber piece that is inserted into the carburettor is 3 cm deep, but this also depends on the depth that is necessary to be able to close the carburettor properly. You may have to work with an intermediate piece, for example in the form of a piece of hose.
Tip : It is faster, clearer and better if you work with two synchronizers, but this is not a requirement.
Note for the universal synchronizer : In the synchronizer there is a valve that you can close or open further, which reduces or increases the air flow and thus the sensitivity of the synchronizer. If the synchronizer does not indicate anything at low rpm, the valve should be closed further until the red float rises in the tube. Conversely, when the red float is continuously at the top of the tube, the valve must be opened further to take a correct measurement.
