Just curious how to do a a 'bench sync' on these carbs?
like what is the usual procedure...
I saw on page 74 of this excellent tutorial that you can use a wire gauge to do a general bench sync...
http://www.mtsac.edu/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf
But it doesnt give much instructions on that specific step so I kinda guessed...
and also read researching tonight: "you can also use a piece of wire as a feeler guage
open the idle screw then close it so the butterfly just touches it. then set then all the same. Done properly a bench test is usually within 1 cm on the actual sync tools and good enough."
I may need more clarification on "open the idle screw then close it so the butterfly just touches it. then set then all the same."...
I noticed one of my butterflies was a lil more open at the bottom than the other side when I used a little upward force in that middle area to open the butterflies and compare that small gap size.
So I put one wire under one carb and turned the balance/sync screw until the left side was about the same and they both completely shut at same time, and looked like both opened at same time. Is that generally correct or more correct procedure is needed to clarify (like details like maybe the throttle stop screw should be completely turned outwards beforehand to do the sync)?
EDIT: i think I kinda figured it out... you turn in the throttle stop screw so the gap slightly opens on left side carb so the wire gauge fits just underneith the left side (left side if engine side of the carb is facing you), then turn the adjuster screw to get the right side so it also can just get the wire to fit underneath the butterfly.
I guess I'd like to do a real sync test with one of those gauges (vs making one)...
Are these the supplies I need:
http://www.amazon.com/Carburetor-Synchronizer-carb-Gauge-cylinder/dp/B004MSJ7C8
http://www.amazon.com/Motion-Pro-08-0040-Carburetor-Adapter/dp/B000OO4PWG
I read somewhere you need a 6mm adapter kit for Yamaha bikes.
Also Mikes XS mentions "Note: Sync gauges hoses hook up to carb holder vacuum air barbs (not included).
Your bike must have these air barbs in order to use this sync tool."
Does the (1978) XS400 have these air barbs to use a sync tool with it?