BASE LINE FOR THROTTLE BODY ADJ SCREW

[GA CYCLE RIDER]

Does anybody know what the baseline for the number 3 cylinder throttle body adjustment screw is. I have the factory manual and it says if you remove the screw you should "turn it in 3/4 of a turn" This makes no sense, shouldnt it be that you back it out 3/4 turn after lightly seating the screw all the way in. BTW, not the first time that the factory manual has left me wondering. Yamaha should consult a Honda manual for the proper way to lay out a service manual.

 

[radman]

!/2 turn out from lightly seated. Idle speed may/will have to be adjusted if way outta whack.

 

[GA CYCLE RIDER]

thanks, RAD. I am off to the garage.

 

[markjenn]

I don't there there is anything magic about the 3/4 turn, but probably a good starting point.

Keep in mind that the further these screws are out, the more "trimming" they do of the sync. So potentially further out gives you more range to correct for mis-sync.

Of course you eventually reach the limit where you have them too far out that your idle speed is too high, even with the idle adjuster backed all the way off. Conversely, in the other direction, you have them so far closed that one or more screws "bottoms out" without being able to get sync.

I've noticed that different adjustments will give the bike a little different feel. Mine sometimes has a nasty gravelly growl as you whack the throttles just off idle that you can somewhat tuned out by the starting position of these screws, although I don't recall now whether having them further out or in helped it.

Fun to experiement.

- Mark