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How to tune honda Cd70 Euro2 Idle mixture

honda cd70 red

honda Cd70 euro2 carburetor have air screw for idle mixture adjustment. the best method to adjust a carburetor idle mixture is balancing the air fuel mixture with the given adjustment range.

carburetor engine side profile

Front or engine side

carburetor adjustment side

Adjustment Screw Side

carburetor air filter side

Air Filter Box Side

Step 1: adjust the idle speed with idle screw to 1500rpm. turn the screw right to increase engine rpm and left to reduce it.

carburetor rpm adjuster screw turn left

Turn Left to decrease the Engine Rpm

carburetor rpm screw turn right

Turn Right to Raise the Engine Rpm

air fuel adjustment Air Screw

Idle Mixture Adjustment Screw in this case ( Air Screw)

Step 2: turn the idle air mixture screw left 1 and half turn for adjusting to factory setting.

then from that point keep turning it quarter turn to the right and wait and check if the engine rpm decreases.

when engine rpm starts to decrease. note that point

now turn the adjuster screw to the left until rpm begins to stumble or irregular.

set the adjuster screw between these two points where engine stumbles or rpm starts to decrease.

for example :

                           1 turn is the point where the engine rpm starts to decrease .and 2 turns is the point where engine rpm begins to get irregular. then 2 and half turns is the point where the idle mixture screw should be set.

idle adjustment screw

Idle Adjustment Screw

Step 3: after adjusting the air mixture screw adjust the rpm with idle rpm screw to 1500rpm.

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