As always, click on the images for detailed view.

Step 1

Add some grease on the both ends of the shaft.

Very much the same assembly as on the right carb ( see the post Right butterfly vavle assembly )

Step 2

Insert the seal with the lips facing outwards. Two seals, one for each end.

Step 3

Insert the shaft and the butterfly valve. Secure the screws with loctite. Use new screws if they are worn.

Note, the text on the valve facing upwards (red arrow on the picture )

Make sure the valve sits well and is the correct position. If not you will get trouble later on doing the synchronization ( balancing ) of the carbs.

Step 4

Step 5

Most of the parts got some seconds or minutes on the polishing machine before mounting, the spring as well. Looks so much better.

Step 6

Step 7

Step 8

DONE !