bluesdog
Well-known member
iirc, it took @ 3 or so sessions before I got mine synched up nicely. Coming up to +53K km now, and it pulls turbine smooth and strong to redline, and I'm still too chicken to WOT in first.
The Really, Definitely Completely Un-Authorized TBS
- Thread starter Fred W
- Start date
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@majbach - Sometimes I think the same thing, that maybe the bike isn't quite as peppy as it used to be. Then I do a little acceleration testing (on a closed test track, of course! 
) through first and second gears, look down and see "ticket me now" speeds reached in only a couple of seconds and realize, I've just become used to the raw power that this bike produces over time. Once you become accustomed to it, and it no longer scares the bajeebers out of you every time you whack the throttle open, you do lose a little bit of the initial adrenaline rush. That doesn't mean that the bike is getting any slower...
) through first and second gears, look down and see "ticket me now" speeds reached in only a couple of seconds and realize, I've just become used to the raw power that this bike produces over time. Once you become accustomed to it, and it no longer scares the bajeebers out of you every time you whack the throttle open, you do lose a little bit of the initial adrenaline rush. That doesn't mean that the bike is getting any slower...
MajBach
Well-known member
Well you have to understand that the inner workings of what is going on is new to me. If this was normally aspirated, I may not be as out to lunch. Don't forget, you did say "It's much better for folks to be actually thinking (you remember how to do that?) about what it is they are doing, or adjusting, or attempting to do, and consider the ramifications and consequences, rather than just blindly going out and following procedures from some knucklehead chump that says: Hey This is the next best thing since sliced bread."
Anyway, I have been revisiting this procedure after coming back from a 3000 mile road trip last week and not being happy with the smoothness of the bike and reading into this thread and others to a little more depth. I was hoping to try and do another sync but this time at idle like you suggested in your most recent update for a Gen Ii. I closed off the bleeder screws and brought the idle right down then used a throttlemeister to hold an idle. I hooked up my sync tool and the manifold were way off. So,I have a few questions I hope you can answer:
- You state to sync the 2-3 adjustments first but how do you determine whether you should adjust the 2-3 to match the other two rather than adjust the other two to match the 2-3?
- In your Gen II procedure, you suggest to adjust the idle first then close off all the bleed screws ( I thought someone else mentioned to try and bring the idle screw all the way out and hold idle using the throttle - I'm not sure which is best) but there is a problem with this as you will have to shut off the bike to adjust the 2-3 and it would be near impossible to get the same throttle when you re-start.
- I fail to understand what is really happening mechanically when you adjust each throttle plate screw. I would presume youre just adjusting the angle of the butterfly valve and with this set up, youre adjusting two at a time. Is this correct? If so, at idle aren't all the valves supposed to be fully closed? Why cant we just back off the screws (or turn them all the way in - whichever the case may be) and then reverse direction until there the movement makes a difference? You'd know then that the valves are all fully closed.
- Finally, and this is a bit outside the box from what we are doing, but correct me where I am wrong: The throttle body valves open in order to allow more air in. In a normally aspirated engine, the increase air flow creates a low pressure and sucks in more fuel. But in a fuel injected engine, isn't that fuel metered depending on what the throttle position sensor says? And, isn't the TPS calibrated to a position set of one of the butterfly valves? In other words, by adjusting the valves positions, are we not in effect screwing up that calibration thereby changing the amount of fuel that is metered for a certain amount of air (throttle position)?
****
Since writing the above, Ive gone down and successfully synced the beast. All four screws are adjusted in, the master idle screw is in just enough to keep the bike running around 900-1000 and all four read very close to each other - at idle, at 4-5k without a load and at 4-5k with a load. Success? I hope so and the bike sounds noticeable smoother since I started. Now here is what I don't understand: why bother screwing around with the bleed screws at all? why not leave them closed and adjust the master idle until I get 1100?
Can someone explain to me the difference between adjusting throttle valves and the bleed air and why does the shop manual state not to ever adjust the former? Why then are they there?
(Why didn't I leave well enough alone? I always have to tinker.)
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Wow... lots of good questions. Let's see if I can answer some.
When you are adjusting the center screw between the #2 and #3 TBs you are actually moving 1 & 2 in reference to 3 & 4. What you want to match when you are done adjusting that screw is #2 to #3. The other ones do not really matter at that point. Once you are happy with that you move on to the outer two. When you adjust the left side screw between the #1 and #2 TBs, you are actually moving just the #1 plate in reference to #2, #3 & #4. Likewise, when you adjust the one on the other side you are moving #4 in reference to #1, #2 & #3.
By eliminating the air screw bypass (closing all 4 all the way) we have just the throttle plates and the idle adjuster air, which makes the small opening of the plates extremely important to the total air, and therefore the balance between cylinders, at idle
Some other bikes have you adjust the TB plates with a feeler gauge, ensuring that each is open exactly (mechanically) the same amount at fully closed. We don't have good access to our throttle bodies (it's a real pain to get at them) so we are doing the UA TBS instead to get them synchronized.
The idle adjust screw is attached via a short cable to the air bypass mechanism (highlighted). When you turn the screw you allow more or less bypass air from the inlet tube (#9) to the four distribution tubes that go off to the individual throttle bodies (#11 x 4).
Theoretically when you adjust that bypass air it would be adding or subtracting an equal amount of bypass air to all 4 TBs, but being a mechanical device that may or may not be the case. Therefore, it is best to have the idle screw adjusted as close as possible to its final position while adjusting the balance or else the balance may be knocked out when you subsequently adjust the idle speed.
Idle speed should be 1000 to 1100 rpm. 1100 seems to work best overall and I use that as my target.
The answer is yes sort of. Yes, the TPS (Throttle Position Sensor) is one of the devices that the ECU uses to determine injector duration (how much fuel is injected). And the TPS is located on the left end of the throttle shaft (it's #15 in the diagram above), so when we adjust the linkages we may slightly change the TPS position. But the actual amount we are varying the throttle shaft is very small, smaller than you would be able to adjust the TPS position by loosening the screws and turning the TPS body (that;s how it is adjusted). Any change in TPS voltage will be too small to be significant.
The air screws, providing a fixed quantity of bypass air at all rpms, have little to no effect on balance at anything above about 3000 rpm. Therefore, if you want to affect the balance above that you need to alter the throttle plate positions slightly to achieve it
You really have been paying attention. And I agree 100%. I've come to the conclusion that you could just close down all 4 air screws fully and adjust the throttle plates for balance, and if you can achieve an adequate idle speed with the idle adjustment then there is no need to ever open the 4 air screws at all. But because of the design, you will probably not be able to reach the minimum idle speed with all the air screw air subtracted from the total. That's why you'd need to open all 4 screws an equal amount ( usually ~ 3/4 turn) and then re-balance the 4 air screws, so that you can achieve the 1000 to 1100 rpm warm idle speed within the adjustment range of the idle adjuster. This applies to both generations.
Hopefully some of the above helps you understand what's going on a bit better.
Let me start off by describing the linkage adjustment. The four throttle body plates are on independent shafts that are each connected through the screw adjustable mechanism. The throttle cable is on the #3 shaft, and on 1st Gens that is where the mechanical idle adjuster is, which is just a screw adjustable stop. 2nd Gens have an additional air bypass circuit for for idle adjusting (more on that later)
When you are adjusting the center screw between the #2 and #3 TBs you are actually moving 1 & 2 in reference to 3 & 4. What you want to match when you are done adjusting that screw is #2 to #3. The other ones do not really matter at that point. Once you are happy with that you move on to the outer two. When you adjust the left side screw between the #1 and #2 TBs, you are actually moving just the #1 plate in reference to #2, #3 & #4. Likewise, when you adjust the one on the other side you are moving #4 in reference to #1, #2 & #3.
No, after everything is adjusted perfectly the butterfly valves are not fully closed at idle. There is actually a secondary screw stop on each TB (one that we never touch) that ensures the valves do not close fully. The air required for the bike to idle is a sum of the air passing through the slightly open butterfly and any bypass air (air screw and idle adjust).
By eliminating the air screw bypass (closing all 4 all the way) we have just the throttle plates and the idle adjuster air, which makes the small opening of the plates extremely important to the total air, and therefore the balance between cylinders, at idle
Some other bikes have you adjust the TB plates with a feeler gauge, ensuring that each is open exactly (mechanically) the same amount at fully closed. We don't have good access to our throttle bodies (it's a real pain to get at them) so we are doing the UA TBS instead to get them synchronized.
As mentioned above, the Gen 2 warm idle adjuster is an adjustable air bypass. Here's a thousand words to describe it below:
The idle adjust screw is attached via a short cable to the air bypass mechanism (highlighted). When you turn the screw you allow more or less bypass air from the inlet tube (#9) to the four distribution tubes that go off to the individual throttle bodies (#11 x 4).
Theoretically when you adjust that bypass air it would be adding or subtracting an equal amount of bypass air to all 4 TBs, but being a mechanical device that may or may not be the case. Therefore, it is best to have the idle screw adjusted as close as possible to its final position while adjusting the balance or else the balance may be knocked out when you subsequently adjust the idle speed.
Idle speed should be 1000 to 1100 rpm. 1100 seems to work best overall and I use that as my target.
You have been thinking!
The answer is yes sort of. Yes, the TPS (Throttle Position Sensor) is one of the devices that the ECU uses to determine injector duration (how much fuel is injected). And the TPS is located on the left end of the throttle shaft (it's #15 in the diagram above), so when we adjust the linkages we may slightly change the TPS position. But the actual amount we are varying the throttle shaft is very small, smaller than you would be able to adjust the TPS position by loosening the screws and turning the TPS body (that;s how it is adjusted). Any change in TPS voltage will be too small to be significant.
Another great question. The manufacturer either sets the relative throttle positions mechanically during assembly, or maybe on a flow bench prior to installing it on the bike, for precise alignment of the throttle plates. They say that they should never need to be mechanically adjusted after that, and that you should only adjust the air screws for balance at idle. But we owners have noticed that this does not always result in the least possible vibration at higher rpms.
The air screws, providing a fixed quantity of bypass air at all rpms, have little to no effect on balance at anything above about 3000 rpm. Therefore, if you want to affect the balance above that you need to alter the throttle plate positions slightly to achieve it
You really have been paying attention. And I agree 100%. I've come to the conclusion that you could just close down all 4 air screws fully and adjust the throttle plates for balance, and if you can achieve an adequate idle speed with the idle adjustment then there is no need to ever open the 4 air screws at all. But because of the design, you will probably not be able to reach the minimum idle speed with all the air screw air subtracted from the total. That's why you'd need to open all 4 screws an equal amount ( usually ~ 3/4 turn) and then re-balance the 4 air screws, so that you can achieve the 1000 to 1100 rpm warm idle speed within the adjustment range of the idle adjuster. This applies to both generations.
Hopefully some of the above helps you understand what's going on a bit better.
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ionbeam
2 FUN
TPS: If you go to diAG and read diAG code 01 for the TPS you can read the actual TPS value the ECU sees. With the throttle closed you should read 15 - 17 (throttle opening in %, the throttle plates have to be cracked enough to maintain idle air flow) with the throttle fully open you should read 97-100 (100% throttle opening with the throttle pinned open) These numbers can vary a bit and you may see a wide open reading of 101 or 102 which is nothing to worry about.
Verity your plugs are OK, I had an issue with my #3 plug cap repeatedly wanting to pop off, not enough to cause a misfire but enough to cause a lack of engine smoothness.
If you aren't having luck fixing the "not being happy with the smoothness of the bike" in the engine, some people have had luck with retorquing the engine mounting bolts. Loosen them slightly and then retorque following the sequence specified in the FSM.
As compelling as dual ENGINE BALANCERS sounds, including little degree marks on the adjusters, they do not actually tune the engine's mechanical balance, all they do is adjust the balancer gear lash.
You have pulled in the clutch while at speed to confirm that the lack of smoothness is the engine and not something in the wheels/chassis?
Verity your plugs are OK, I had an issue with my #3 plug cap repeatedly wanting to pop off, not enough to cause a misfire but enough to cause a lack of engine smoothness.
If you aren't having luck fixing the "not being happy with the smoothness of the bike" in the engine, some people have had luck with retorquing the engine mounting bolts. Loosen them slightly and then retorque following the sequence specified in the FSM.
As compelling as dual ENGINE BALANCERS sounds, including little degree marks on the adjusters, they do not actually tune the engine's mechanical balance, all they do is adjust the balancer gear lash.
You have pulled in the clutch while at speed to confirm that the lack of smoothness is the engine and not something in the wheels/chassis?
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Good point. Even when it is perfectly adjusted, there is still some vibration that remains unbalanced by the balance shafts.
Doing a TBS can help reduce vibration, but some of it is always there, just to let you know you have 150 ponies whirling away between your knees...
Doing a TBS can help reduce vibration, but some of it is always there, just to let you know you have 150 ponies whirling away between your knees...
MajBach
Well-known member
Haven't had a of opportunity to review this until today. Thanks for taking the time to respond in detail and your explanations certainly clear up most of my questions. i particularly benefited from how you described how the the throttle body plates and adjusters work.
Thanks again
lnewlf
Well-known member
finally did Fred's TBS....couldn't get #1 perfect...if I set it even with #2 at idle it pulled to hard at higher rpms so I left it slightly lower at idle and from 2K up they all pulled very close....but
when I opened the air screws @ 1 turn, idle sync was all screwed up and higher rpm sync was not as good either so I left them closed..I didn't like how loose the screws seemed either-wondered why they hadn't already fallen out. With them closed idle was 1200 with the idle knob [Genll] set in the middle of it's range..
no time for a test ride yet-hope it runs as good as it did before....smooth as buttah and fast as a violated simian...
when I opened the air screws @ 1 turn, idle sync was all screwed up and higher rpm sync was not as good either so I left them closed..I didn't like how loose the screws seemed either-wondered why they hadn't already fallen out. With them closed idle was 1200 with the idle knob [Genll] set in the middle of it's range..
no time for a test ride yet-hope it runs as good as it did before....smooth as buttah and fast as a violated simian...
I hope it works out for you, too.
It sounds, from your description, a bit like maybe you have some air leaks in the throttle bodies. Maybe the shaft bearings are getting worn and admitting a bit of extra air at the high vacuum of idle. You wouldn't be the first, especially if you have accumulated as many miles as I assume that you have by now
It sounds, from your description, a bit like maybe you have some air leaks in the throttle bodies. Maybe the shaft bearings are getting worn and admitting a bit of extra air at the high vacuum of idle. You wouldn't be the first, especially if you have accumulated as many miles as I assume that you have by now
lnewlf
Well-known member
Well, that was fun......the reason I was motivated to do Fred's TBS was because the idle was creeping up to almost 1500..... I had previously checked all the usual stuff-lube the cables, adjust slack and even back out the idle knob to the point where the screw fell out..[not recommended].
I was satisfied with the result of the TBS altho the lowest I could get the idle was 1200 with the air screws turned full in..
took her for a test ride and about 20 miles away realized that the idle was now about 2500 !! fun ride back to the garage.
got under the tank and after a half hour of scratching my nutz I noticed that a screw that secures the bracket that clamps the throttle cables just above the lower pulley had backed out about 1/2 inch an was preventing the pulley from going all the way to it's stop. Like an idle adjustment screw, the further out it got, the faster the idle... beautiful. Weaseled a long screwdriver in there and tightened it back down with a drop of blue Loctite.
I never touched that screw and it had Yammies blue dot on it...this could have worked out bad...bet I'm the only one this has happened to....
I was satisfied with the result of the TBS altho the lowest I could get the idle was 1200 with the air screws turned full in..
took her for a test ride and about 20 miles away realized that the idle was now about 2500 !! fun ride back to the garage.
got under the tank and after a half hour of scratching my nutz I noticed that a screw that secures the bracket that clamps the throttle cables just above the lower pulley had backed out about 1/2 inch an was preventing the pulley from going all the way to it's stop. Like an idle adjustment screw, the further out it got, the faster the idle... beautiful. Weaseled a long screwdriver in there and tightened it back down with a drop of blue Loctite.
I never touched that screw and it had Yammies blue dot on it...this could have worked out bad...bet I'm the only one this has happened to....
FJRMGM
FJRMGM
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<blockquote class='ipsBlockquote'data-author="Auron" data-cid="1272202" data-time="1448208730"><p>
Is there any reason this wouldn't work just well on any other I-4? I've got a 600 that's pretty darn buzzy and this mod worked wonderers on my AE. </p>
</blockquote>
Should work on all inline fours that you can sync.
Is there any reason this wouldn't work just well on any other I-4? I've got a 600 that's pretty darn buzzy and this mod worked wonderers on my AE. </p>
</blockquote>
Should work on all inline fours that you can sync.
Auron
FJRForums' Red-headed stepchild
There seems to be a great variation on how people interpret a buzzy bike. It's usually dismissed as a personal thing like windscreens, but I'll bet it becuase some bikes are just synced better than others.
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I'd like to add my experience to this excellent thread...
As a bit of background, 5 years ago when I decided to buy a GenI FJR I rode 4 or 5 different 04/05's. Within the first 100 yards of the test drive of the bike I ended up buying I remember thinking 'This is the one I'm going to buy.' It just seemed to run better/smoother than any of the others. I've always wondered if it really was any different or if I was just ready to buy a motorcycle that day.
Over the proceeding 5 years/35,000 miles I've done most of my own maintenance including a couple TBS's and have been satisfied with the results. I had followed the idea of the UA TBS and specifically this thread with interest as many guys have been so happy with the results, but I had just never felt comfortable with doing it myself. Then, about a week ago I happened to re-read post #1. Thanks to Fred's excellent summarizing/simplifying I felt like I finally really understood and could handle performing this procedure.
To make a long story short, when I got in there and got the Carbtune hooked up, guess what? They were damn near even already! So I took a look at Yamaha's little white 'We can tell if you've touched this!' stripe on the adjuster screws and guess what? Somebody beat me to it! A 5 year old question in my mind had finally been answered! I now believe this bike did actually run better/smoother than the other FJR's I had ridden thanks to a PO (there had been 2) taking the time to perform this procedure. Actually #4 had gotten just a bit low, not surprising as it had been at least 5 years since the UA TBS had last been performed, so I tweaked the screw, finished the rest of the procedure, buttoned it back up and took it out for a test drive.
I do think it runs a bit smoother (again!) so that's nice and a better understanding of my bike is an added benefit. And thanks again to Fred for his time spent editing this post and to all who contributed to the knowledge base. This really is a great community!
As a bit of background, 5 years ago when I decided to buy a GenI FJR I rode 4 or 5 different 04/05's. Within the first 100 yards of the test drive of the bike I ended up buying I remember thinking 'This is the one I'm going to buy.' It just seemed to run better/smoother than any of the others. I've always wondered if it really was any different or if I was just ready to buy a motorcycle that day.
Over the proceeding 5 years/35,000 miles I've done most of my own maintenance including a couple TBS's and have been satisfied with the results. I had followed the idea of the UA TBS and specifically this thread with interest as many guys have been so happy with the results, but I had just never felt comfortable with doing it myself. Then, about a week ago I happened to re-read post #1. Thanks to Fred's excellent summarizing/simplifying I felt like I finally really understood and could handle performing this procedure.
To make a long story short, when I got in there and got the Carbtune hooked up, guess what? They were damn near even already! So I took a look at Yamaha's little white 'We can tell if you've touched this!' stripe on the adjuster screws and guess what? Somebody beat me to it! A 5 year old question in my mind had finally been answered! I now believe this bike did actually run better/smoother than the other FJR's I had ridden thanks to a PO (there had been 2) taking the time to perform this procedure. Actually #4 had gotten just a bit low, not surprising as it had been at least 5 years since the UA TBS had last been performed, so I tweaked the screw, finished the rest of the procedure, buttoned it back up and took it out for a test drive.
I do think it runs a bit smoother (again!) so that's nice and a better understanding of my bike is an added benefit. And thanks again to Fred for his time spent editing this post and to all who contributed to the knowledge base. This really is a great community!
NTXFJR
Well-known member
I did this procedure on my bike yesterday. The vacuum tweaks were a real pita for me to get them right, but with a little patience, I did end up with some great readings. I set the air screws at 1 turn afterward. Bike is running better than ever both city and power slabbing it.
Many thanks to Fred for posting this!!
And I would recommend not forgetting to replace the rubber port caps when done. Don't ask me how I know......
Many thanks to Fred for posting this!!
And I would recommend not forgetting to replace the rubber port caps when done. Don't ask me how I know......
Hi Guys,
I have been trying to apply the above procedure to my 2013 model, but the idle speed seems to be controlled by the ECU on this model - at the time I was doing it, I phoned up an acknowledged expert over here (in the UK) and he wasn't sure as had not done one, and another had said that it was the ECU that controlled idle on this model... I didn't have time to get to the bottom of the issue at that time but now want to do the job.
So, can anyone confirm whether this procedure needs to be modified for the 2013 model ( it's Gen 4 in the UK but maybe Gen 3 in the US - whatever, it's the 2013 - 2015 model)
Thanks,
Nick
I have been trying to apply the above procedure to my 2013 model, but the idle speed seems to be controlled by the ECU on this model - at the time I was doing it, I phoned up an acknowledged expert over here (in the UK) and he wasn't sure as had not done one, and another had said that it was the ECU that controlled idle on this model... I didn't have time to get to the bottom of the issue at that time but now want to do the job.
So, can anyone confirm whether this procedure needs to be modified for the 2013 model ( it's Gen 4 in the UK but maybe Gen 3 in the US - whatever, it's the 2013 - 2015 model)
Thanks,
Nick
ionbeam
2 FUN
Yes, the procedure needs to be updated for the '13 and up. The idle is indeed controlled by the ECU and needs a computer interface ($600 USD) to adjust the idle speed or it would need to go to a dealer. I'm sure Fred W will be along.....
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Actually, none of this procedure works on a third gen since they also eliminated the ability to adjust the throttle plates linkage.
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