Throttle body sync on a modern fuel injected bike?

[racefactory]

Is it really necessary?

[DEATH_INC.]

It should be part of your service plan, they go out just like carbs do. It's just not as noticeable as carbs are.

[racefactory]

It should be part of your service plan, they go out just like carbs do. It's just not as noticeable as carbs are.

What are the symptoms of it being out of sync?

[neels]

If you want all of your cylinders running the same, then probably yes.

If air flow measurement which is common to all cylinders is used to calculate fuel, then different throttle openings could give you a different air flow to each cylinder, but the same fuel input from the injector.

[Max Preload]

Yes, still neccessary. The O2 sensor (if used) only measures the combined air:fuel ratio of all the cylinders and makes injector pulse width adjustments across all cylinders based on that. But if one cylinder is still getting more air due to less restriction due to butterfly miss-synchronisation it'll be a little lean and the other cylinders will be a little rich. Also, the engine won't be quite so smooth if the butterflys aren't properly synchronised, particularly at idle.

[DEATH_INC.]

What are the symptoms of it being out of sync?

Also, the engine won't be quite so smooth if the butterflys aren't properly synchronised, particularly at idle.

What he ^^^^ said

[bsasuper]

You dont actually adjust the throttle butterflys on a injected bike, you adjust the air bleed screws at idle.The butterflys are set for life at the factory.

[vifferman]

Yeah, what they all said. O2 sensors?!? Mine have been put to sleep - no lean surge for me, thenkee very much. Throttle body sync only really makes a noticeable difference at idle and low revs. I've had my EFI'd VFR for.... hmmm... 6 years now, and only sync'd (well... actually on my model, out-of-sync'd) once, shortly after I got it. For all I know, the valve clearances have never been done. I *do* change the oil occasionally though, and last week I cleaned and re-oiled the Unifilter.
Seems to go OK, especially with the current PC map.