Butterfly valves

[andybb]

GS500ET 1996
Just rebuilt some carbs. What size gap do I need under the butterfly valves so I can get them sinked before I fine tune them when its running.

[herennow]

you should sync them with vacuum gauges, without that just make sure they have the same gap.

[Joolstacho]

You just need a starting point don't you? I'd suggest using something like a 1.5mm drill bit underneath the butterfly. This will ensure that they are the same.

[Bluesmudge]

2nd for bench sync is just a starting point. A paper clip uncurled, a feeler gauge, whatever. Check it after installation with a vacuum gauge.

[andybb]

Thanks for the replies.
Yes, I was looking for a starting point before fine tuning. Mine have zero gap at the moment.
Let you all know how I get on with my tinkering but at the moment, unheated garage and it's Brrrr.



 
   

[herennow]

remember that the gap is controlled by the idle adjust screw (which is different to the butterfly sync screw which controls them relative to each other) The overall gap will be adjusted on a arm bike to get the correct idle speed.
Get two of these and you are golden for synching the butterflys, will cost more to buy 3 meters of tubing and a litre of ATF 🤣.

[The Buddha]

I never liked the drill bit or any other object in there method. I synch them by looking at a bright part of the sky - not directly at the sun.

Cool.
Buddha.

[gruntle]

Sadly not all of us have reached the deep Zen understanding of the venerated Buddha whilst meditating upon butterflies...

[andybb]

Thanks for all the replies,