Reassembling the carbs after a deep clean...My carbs are off the engine and I want to test to see if the slide diaphragms are sealed properly around the outer edge under the carb top cover. Is there a way to test with a vac-pump. The diaphragms seem to have shrunk some and I had trouble seating them upon reassembly. Any advise appreciated.
Carb Slide Diaphragm
- Thread starter sparke
- Start date
I would stick my finger in the carb throat and lift the slides. Watch how long it take for them to return to closed when you remove your finger. If one is faster than the others, look into the diaphragm seating again. There is a video on youtube showing the proper way to position the neoprene part. You push it down so it looks like a skirt. Then you push the slide down into the bore and the diaphragm should seat the way it should without touching it again. The material they are made of should not shrink. Go to the 19 minute mark here for a demonstration.: https://www.youtube.com/watch?v=95nlrP-yn2I&nohtml5=False
One way to test the diaphragms is to blow air (using your mouth) into the large air vent pipes between the carbs, the ones that have the thick rubber pipe that goes to the secondary air cleaner at the steering head.
Doing this applies extra air pressure under the diaphragm which in absolute terms is the same as applying a vacuum above the diaphragm. By doing this while holding the throttle butterflies open, I was able to see the pairs of slides rise and fall in the carb venturi.
Doing this applies extra air pressure under the diaphragm which in absolute terms is the same as applying a vacuum above the diaphragm. By doing this while holding the throttle butterflies open, I was able to see the pairs of slides rise and fall in the carb venturi.