Could someone explain the function of the VOS to me please. I don't know if newer models use them, but my '99 does. I'm still getting to know it, bought it second hand this spring and haven't had much time to tinker.

Today I did notice some electrical tape unwinding from the vacuum tubing that connects the carb, petcock and VOS. The tubing was hard and cracked and so was the tape that the previous owner had used to fix the break in the tubing.

Just wondering what VOS is for and (besides the obvious), what a vacuum leak in the tube would affect.

Thanks

 

At zero vacuum (at starting) it retards the spark timing by 4 degrees. A faulty switch will cause hard starting, including backfiring.

 

Only used on carbureted models up to 06' to my knowledge? But the above description that Dorkman says pretty much nails it.
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it will make starting hard and hard accel rough or sluggish or pingy

just buy 6 inches of 1/4 tube, doesnt even matter what kind, nothing is going to be in there, and hold the ends tight with a small blav UV resistant zip-tie. perfect replacement, you can do it without taking anything apart but its difficult. easiest way is to take the carb out, dont worry it just pushes back onto the manifold and the air cleanr just bolts on, nothing hard about it

 

A leak in that vacuum line will cause the bike to shutdown like you ran out of fuel....Don't ask how I know.

 

Thank you for the replies, and the information.

I already have the tank off and the tubing out, so everything not in good shape will get replaced. The switch is located above the front cyclinder between the coils so I would like to get tubing that will stand up to the heat. The tubing that is being replaced is all hard and dry, obviously had trouble with the heat. One section even has plastic looming around it, but it still didn't seem to help.