2013 Throttle Body Sync has gone wrong somewhere

[hitbyastick]

Hello,

For the first time since the bike got its 1000 or so mile tune-up, I checked the throttle body sync. All 4 screws were fully bottomed out (i.e. screwed in). Subsequently, I could not do any adjustment to match the #1 cylinder (only if I backed this screw out slightly, which is apparently a no-no).

There were no paint marks or any other things on the adjustment screws.

How can I rectify this situation so I can get my TB's all synced up and running smoothly. I am now at 15K miles and would like to give it a good tune-up.

Thanks,
Christoph

 

[Queensland Ken]

Just back off all the air bypass screws 1 1/2 turns and start from there.

The idle speed control should compensate for the change in RPM.

 

[Fred W]

That doesn't appear to be what is being done from the factory on the 3rd gens. Here is my recommendation for reproducing the factory method:

1) Screw all 4 air adjust screws all the way in to lightly seated

2) Find the one that has the lowest vacuum. That will be your reference channel. That is the one that the factory paints with a white dot (and leaves fully closed)

3) Adjust the other 3 circuits to match your reference. (opening an air screw will cause that circuit's vacuum to drop)

My guess is that when they closed all 4 of your screws at the factory they were found to be close enough to each other to require no adjustment as is, and that was also why none of your screws was painted as the reference. You have the perfectly synchronized throttle already.

On the 3rd gens the idle speed adjustment is accomplished electronically and automatically via the YCC-T (Fly By Wire Throttle). There is no longer an ISC (Idle Speed Control) bypass mechanism like in the earlier gens. What that means is that by minimizing the bypass air through the TBS bypass circuits you will be allowing the YCC-T to open the throttle plates themselves further, which is the ideal situation.

 

[Queensland Ken]

I only mentioned the ISC, which is a function of the ECU, in case the RPM change as you balance out the TB.

You can reset the idle speed control, diagnostic 67.

If the RPM "flutters" at idle, a diag 67 may reduce/ stop it.

 

[Denver_FJR]

On the 3rd gens the idle speed adjustment is accomplished electronically and automatically via the YCC-T (Fly By Wire Throttle). There is no longer an ISC (Idle Speed Control) bypass mechanism like in the earlier gens. What that means is that by minimizing the bypass air through the TBS bypass circuits you will be allowing the YCC-T to open the throttle plates themselves further, which is the ideal situation.

Sorry about bit of an aside, but have they also done away with cold start air circuit (controlled by coolant temp). Would also seem superfluous with YCC-T.

 

[Queensland Ken]

Good hey what !

No more fast idle valves and wax motors / fuses.

 

[Fred W]

Yep. High idle is all achieved electronically via YCC-T. The enrichment was always done in the ECU via fuel injection, the wax motors just bumped the cold idle speed up via an additional air bypass circuit in each throttle bore.

 

[Constant Mesh]

A question for the Gen III owners ---

After you start the bike when it's warm (no elevated idle) and start moving in 1st gear will the bike pull itself up a grade while idling -- no throttle grip input?

Will it hold a constant idle rpm when it's moving under load with no input from the rider?

What is the cold start idle rpm?

 

[mcatrophy]

I expect this is a bit off topic ...

A question for the Gen III owners ---

After you start the bike when it's warm (no elevated idle) and start moving in 1st gear will the bike pull itself up a grade while idling -- no throttle grip input?

Will it hold a constant idle rpm when it's moving under load with no input from the rider?

What is the cold start idle rpm?

In any case I'm probably not too much help, mine is a Gen III YCC-S (FJT1300AS), so I expect things are a little different on an 'A'.

My clutch won't start to engage until a couple of hundred rpm above idle, and disengages when the speed drops to near idle.

However, cold idle is about 1800, drops within a few tens of seconds to warm idle of 1100 (two to five minutes in this weather if I ride straight away, which I generally do). That's the only part I can answer.

FYI: In 1st gear 1100 rpm corresponds to 7.6 mph, 1800 rpm is 12.5 (my reference here).