I am having trouble synchronizing my 3rd body. I get the other ones within specs. But my adjusting screw on the 3rd one bottoms out before I can get it up enough to match the #1 which is the master on the vacuum gauge. Any ideas?
Synchronization of throttle bodys on 2013 FJR
- Thread starter Javlin3
- Start date
Help Support Yamaha FJR Motorcycle Forum:
There is a recent discussion on this over in the Technical/Mechanical section: https://www.fjrforum.com/forum//index.php/topic/162355-2013-fjr-1300-synchronizing-throttle-bodies/
The #3 TB should/could be your std/reference for the others and may have a dash of white paint on the adjustment screw....
Mr. BR
The #3 TB should/could be your std/reference for the others and may have a dash of white paint on the adjustment screw....
Mr. BR
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Pterodactyl
Well-known member
On Gen 3 bikes the number one cyl is the reference and has the white paint.
Queensland Ken
Well-known member
The service manual says you have to clean the throttle bodies if you can't get them within the 10 mmHg specification.
Most likely have some gunge within the air venturies / butterflies at the front of the injectors.
Most likely have some gunge within the air venturies / butterflies at the front of the injectors.
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You have a 2 year old bike. Unless you've managed to amass an unusually high amount of miles in that short amount of time I seriously doubt that your throttle bodies are spooged up (yet).
Question: Does the vacuum drop as you open the #3 screw as it should? If so then the air passages are clear.
Before you go too far, make sure that you swap the hoses on your balance gauge to be certain you are not just seeing a problem with the gauge
My theory on how the factory selection of the "reference" cylinder goes (yet to be conclusively proven) is that they close down all four of the air screws and look at the vacuum on the sync gauge. They paint a white dot on the screw of the cylinder than has the least vacuum, and then open the screws up on the other three to match that one. The idea being this will introduce the least bypass air into the system and give the greatest degree of control to the ECU controlled throttle at idle. So the white dot screw should be fully closed and lightly seated from the factory. Should you choose to adjust the white dotted reference screw you can confirm or deny my theory.
If the air screws appear to be working normally and dropping vacuum as they are opened, and you have ruled out a mis-balance in your gauge, I would just do the same thing that (I surmise) they did at the factory and close all four and balance the other three to whichever has the least vacuum.
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Good write up and good understanding. The reference screw is NOT always the number one cylinder, see above. It NORMALLY is. It could actually be any one of the four. Whichever It is, however, it is always marked with white paint.
TownsendsFJR1300
Well-known member
If you crack #1 OPEN maybe 1/4 turn, you should be able to get more adjustment out of your other air screws...(and sync them up)
TownsendsFJR1300
Well-known member
Any updates??
I'm going to post my experience here rather than starting yet another 3rd Gen TBS thread. I just hit 5k miles and performed my second service (First was at ~ 600 mi). Essentially this was just an oil change and a few added checks, took only a little over an hour and a half all told.
Part of that service was doing a TBS. Many others have reported that the only adjustments we have are the air bypass screws at idle, as the factory has eliminated the linkage adjusters between throttle body butterflies.
One piece of info that I was able to collect supports my theory that the reference screw (painted with the white dot) is fully closed from the factory. Before I even started, I broke the paint free and found that the screw was previously fully closed and lightly seated So I think my theory (posed earlier above) is correct, that the factory just closes all 4 air screws and then just paints the one that has the lowest vacuum of the four while in that condition, and then opens the other three screws to match the new "reference". That would explain why it is usually #1 (mine is) but not always.
FWIW I had no trouble getting the screwdriver on the screws to adjust them. Not sure what the big hubbub is all about there. Just reach under the tank and poke the small screwdriver (tweaker) through the hoses and cables along the fuel rail. In my case the adjustments were not off very far. I seriously doubt that I will be able to feel any difference from having done this adjustment. Since this is the only adjustment that we have, and it will primarily affect the balance at idle with quickly diminishing benefit at higher rpms, I think this is going to be a maintenance that can be done once and then ignored for a very long time.
Part of that service was doing a TBS. Many others have reported that the only adjustments we have are the air bypass screws at idle, as the factory has eliminated the linkage adjusters between throttle body butterflies.
One piece of info that I was able to collect supports my theory that the reference screw (painted with the white dot) is fully closed from the factory. Before I even started, I broke the paint free and found that the screw was previously fully closed and lightly seated So I think my theory (posed earlier above) is correct, that the factory just closes all 4 air screws and then just paints the one that has the lowest vacuum of the four while in that condition, and then opens the other three screws to match the new "reference". That would explain why it is usually #1 (mine is) but not always.
FWIW I had no trouble getting the screwdriver on the screws to adjust them. Not sure what the big hubbub is all about there. Just reach under the tank and poke the small screwdriver (tweaker) through the hoses and cables along the fuel rail. In my case the adjustments were not off very far. I seriously doubt that I will be able to feel any difference from having done this adjustment. Since this is the only adjustment that we have, and it will primarily affect the balance at idle with quickly diminishing benefit at higher rpms, I think this is going to be a maintenance that can be done once and then ignored for a very long time.
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escapefjrtist
Searching for Dry Roads
At last weekends PNW Tech Day, Panman was our TBS guru. IIRC he looked at four GEN III bikes and all were within factory specs.
This pic happens to be from a '13, the others looked very similar. I'm with Fred on this maintenance item...check it and then forget it for quite some time.
--G
This pic happens to be from a '13, the others looked very similar. I'm with Fred on this maintenance item...check it and then forget it for quite some time.
--G
Pjotr
Member
Javlin,
I do have exactly the same problem on my 2013 FJR. My 3rd body bottoms out. So what did you do to solve this?
Pjotr
You use the 3rd throttle body as your guide, match the others to that one. If you look the adjusting screw will have a dab of paint on it indicating that this is the master and all others to match this setting. At least this is what I used on my 2006 and 2017, I also found this somewhere on the net.
Pjotr
Member
Dodger,
Thank you for your answer. My gen 3 has the white dot on TB1. TB3 cannot be adjusted any further. So the white dot on TB1 was my concern, since the manual states to never touch that. It would effect idling etc. I’ve read on the forum that in reality you shouldn’t be bothered too much. It was recommended to close all four bypasses and use the TB# with the lowest vacuum as reference and adjust the other three to that one. However, I’ve not seen any feedback from people who actually did this and he results.
I didn't touch the dabbed screw but matched the others to this one, interesting that yours is #1. I reality when I plugged the manometer into the throttle bodies there really wasn't a lot of difference and I didn't notice much difference in running. I have now done the '17 twice. On the '06 the wiring to the tank can get disturbed and you must be careful to be sure it is plugged back in properly, don't ask me how I know this!
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