Throttle Body Sync Question

[user 89595]

07 model. I had 2 brothers exhaust on the bike and did not like them (Don;t like the rumble). I put OEM exhaust back on this weekend.

When I performed the throttle body sync, I noticed something I have not seen before. All 4 cylinders are even on the scale. If I bump the throttle, they all come back to the same level. But if I run the throttle up to about 3000 RPM and release the grip, No. 3 returns much slower than the others. They will settle out even after about 2 seconds. But the initial return is much slower on No. 3. The bike runs fine. I love the sound now. Runs very smoothly.

Has anyone seen this before?

 

[Fred W]

Yes. I believe it has more to do with the instrument than the actual vacuum. Try swapping the hoses between ports and see if it follows the hose. It is probably just that the inline restriction orifice is smaller on that one hose. I do not pay any attention to the rate of change, just what the levels settle out to.

 

[C&C]

While I have no data to prove/disprove what Fred says, I also believe, and was going to respond, in kind to Fred's response. Swapping the vacuum lines should be definitive.

 

[user 89595]

Thanks fellas. Makes sense. I will have time this weekend to set it up again and test that theory.

 

[FJR-RemingtonRider]

If I may.

After breaking in the new 18'

was about to do the break in service, oil, filter, rear oil, check torque values on wheels, and of course Throttle Body Sync.

Was watching TwoWheeledObsession video and he shows the sync on his 14' and he was saying the #1 cylinder (far left) was the constant to adjust to.

Then while reading the BinOFacts for Gen 3, it was said and shown in pictures that the #3 was the constant to adjust to.

Which is it? does it change year to year?

Haven't obtained a manual yet, so don't know what the 2018 model constant cylinder is.

Who can share which cylinder is the constant to adjust the other 3 cylinders to?

Thanks......

 

[mcatrophy]

It's the one with the white paint on it. Selected in the factory according to the particular engine's characteristics.

 

[FJR-RemingtonRider]

Awesome, Thanks mcatrophy'.....

 

[blue2006kcj]

I had th same Q about the constant. Thanks for the info. I have new to me 06. Only 6700 miles but it stumbles when rolling on throttle or esp dropping g from 3rd to 2nd and trying to roll on throttle bike if very jerky. Thinking its Out of sync TBSs.

 

[RossKean]

I had th same Q about the constant. Thanks for the info. I have new to me 06. Only 6700 miles but it stumbles when rolling on throttle or esp dropping g from 3rd to 2nd and trying to roll on throttle bike if very jerky. Thinking its Out of sync TBSs.

While it isn't a bad idea to do a TBS, I don't think it is going to help your situation very much. The early Gen II are known for a snatchy throttle at low throttle openings. Setting your idle speed up to 1100 or so will help a bit. Some people have found that a G2 throttle tube (https://www.g2ergo.com/) is a significant improvement. Also, you need some amount of slack in the throttle to prevent binding but it should be adjusted to be fairly small (1-2 mm of throttle grip twist, IIRC).

The "favorite" solution to this behavior is a Dynojet Power commander. A "smoothness" map on the PCIII will richen up the overly lean stock mapping and reduce the roll-on jerkiness. Depending on the mapping, it may cost you a couple mpg in fuel economy.

Also, at least for the Gen II, it doesn't really matter much which cylinder is used as the "base" for the TBS. It is important that they are all pretty close to the same as each other when you are done. A lot of people will close all four screws in until lightly seated and open them all up 3/4 of a turn as a starting point. If, at the end of it, you can't set the idle speed where you want it using the idle adjust screw, you might have to pick a little different starting point. The FSM talks about an absolute measured initial vacuum but most of us use a four channel differential manometer for TBS and a more-or-less arbitrary starting point.

 

[escapefjrtist]

^^^^ White paint mark applies to model year '13 and newer when equipped with YCCS or Yamaha fly-by-wire throttle. Previous GEN IIs were synced to #3 but in reality, as long as all four are equal it doesn't matter much.

On the '06, check your idle speed and insure it's at least 1100 rpm, 1200 is even better. '06 & '07 models were especially jerky with the on/off throttle transition.

~G

Edit: RK types faster than I do!! Good information there.

 

[blue2006kcj]

Wow thanks guys. Thats helpful, and gives me a place to start. Seems I need to get the idle up first.

Wow thanks guys. Thats helpful, and gives me a place to start. Seems I need to get the idle up first.

 

[lnewlf]

what he said in post #9....also doing the barbarian jumper mod and moving the CO2 settings up 7 seems to help off idle response...[i didn't use the Power Commander] Best cure for the jerky throttle is wrist training...

 

[rbentnail]

what he said in post #9....also doing the barbarian jumper mod and moving the CO2 settings up 7 seems to help off idle response...[i didn't use the Power Commander] Best cure for the jerky throttle is wrist training...

Yep, all this ^^.

blue2006kcj, I sent you a PM.

 

[blue2006kcj]

yes rbentnail. I think I did get it