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View Full Version : Throttle body sync on a modern fuel injected bike?


racefactory
12th January 2011, 09:39
Is it really necessary?
DEATH_INC.
12th January 2011, 10:11
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
12th January 2011, 10:25
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
12th January 2011, 10:32
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
12th January 2011, 13:00
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.
12th January 2011, 13:34
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
12th January 2011, 14:46
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
12th January 2011, 19:45
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.