throttle body sync

timalan · Apr 17, 2007

I want to do my own sync.

have done connies carbs...

but never done a fuel injected.

any how to recommendations ?

how to leave fuel supply attached .... haven't looked but, I am looking for pointers.

thanks ahead,

'07 A model

timalan

03HiYoSilver · Apr 17, 2007

Timalan,

This is a link to Warchild's TBS instructions. It should be pretty much the same on your GenII model.

https://www.fjrtech.com/getdbitem.cfm?item=21

It is amazing how this operation smooths out the bike and probably surely needed after it starts breaking in.

Hope this helps...

Geezer · Apr 17, 2007

From experience, be careful not to lose the rubber caps from the vacuum ports. I use a small captive spring hook to hold the cap retaining wire and pull the cap off with the retaining wire still on the cap. This is not the exact same one I have, but it is very much like this.

S76 · Apr 17, 2007

I used a lamp table. Put it on the left side of the bike. Rotate the fuel line over and to the tank. If you undo a couple zip ties you will get enough wire to plug in the fuel pump. Then you have free access to the TB's and can run it all day like this.

Caution: Gasoline will destroy that nice finish on your wifes favorite Lamp Table making this job more hazardous and painful than you can imagine!

Go ahead....ask.

timalan · Apr 17, 2007

ok simple and straight forward.

So is the idle adjust done the same way only with #3 then matching the rest or is there and Idle adjust for all four in one spot?

Thanks for the info .... ya'll are a wealth of info. Thanks for the tip on the lamp table thing. I got a cb 750 engine sitting on our OLD dinning room table now. The oops replacement is in the dining room!

Timalan

Bustanut joker · Apr 18, 2007

S76 said:
Caution: Gasoline will destroy that nice finish on your wifes favorite Lamp Table making this job more hazardous and painful than you can imagine!
Go ahead....ask.

Okay, I'll bite :lol:

:jester:

radman · Apr 18, 2007

I've been doing synch's in a different fashion after having done a few hi-speed unauthorized synchs and a few regular (normal) synchs. I've found this method gives very accurate vac readings with little additional work.

1) Set up gauge etc normally.

2) Adjust all the TB bleed screws to 1/2 turn open. This eliminates the bleed settings from the equation.

3) Check readings

4) Now, rather than adjust bleed screws, adjust the throttle plate screws to get even readings instead. At idle.

5) Crank rpm's to 4500 and observe readings, adjust plate screws as needed-shouldn't take but the smallest adjustment to get all in line.

6) Allow bike to idle, adjust idle speed, NOW adjust bleed screws for even readings. Once again, should be pretty damn close.

7) Buzz up to 4500 rpm's again. Bleed settings will alter speed settings very slightly, unless a bleed screw is cranked way out of whack compared to the others-3 turns out on #2 for instance. This indicates something is crossed up, reset all to 1/2 turn and start over.

8) Bleed screws should only need the slightest adjustment to even up the idle numbers. Actually, if all is happy in motorville, you may find they need no adjustment at all, other than turning all down 1/4 turn to get idle speed to about 1000-1100 rpm. Mine are all at about 1/2 turn, this seems to be best.

Keep in mind a synch is done to get 4 cylinders to operate as one-this is the key to smoothness and good power/mileage/rideability. Done right, with care and attention to detail, you won't believe how smooth you can get this motor to run. Another suggestion is to do the high speed adjust at the rpm you find yourself using most often, though the 4500 tends to be the peak vibe number for this motor.

RenoJohn · Apr 18, 2007

radman said:
I've been doing synch's in a different fashion after having done a few hi-speed unauthorized synchs and a few regular (normal) synchs. I've found this method gives very accurate vac readings with little additional work.1) Set up gauge etc normally.

2) Adjust all the TB bleed screws to 1/2 turn open. This eliminates the bleed settings from the equation.

3) Check readings

4) Now, rather than adjust bleed screws, adjust the throttle plate screws to get even readings instead. At idle.

5) Crank rpm's to 4500 and observe readings, adjust plate screws as needed-shouldn't take but the smallest adjustment to get all in line.

6) Allow bike to idle, adjust idle speed, NOW adjust bleed screws for even readings. Once again, should be pretty damn close.

7) Buzz up to 4500 rpm's again. Bleed settings will alter speed settings very slightly, unless a bleed screw is cranked way out of whack compared to the others-3 turns out on #2 for instance. This indicates something is crossed up, reset all to 1/2 turn and start over.

8) Bleed screws should only need the slightest adjustment to even up the idle numbers. Actually, if all is happy in motorville, you may find they need no adjustment at all, other than turning all down 1/4 turn to get idle speed to about 1000-1100 rpm. Mine are all at about 1/2 turn, this seems to be best.

Keep in mind a synch is done to get 4 cylinders to operate as one-this is the key to smoothness and good power/mileage/rideability. Done right, with care and attention to detail, you won't believe how smooth you can get this motor to run. Another suggestion is to do the high speed adjust at the rpm you find yourself using most often, though the 4500 tends to be the peak vibe number for this motor.

Interesting ......when you do the 1/2 turn ..is that and educated guestimate on your part to eliminate bleed settings or did this come from a more concise equation?

I guess what I'm asking, I'd think you'd need a baseline for vacume value and then work from there to balance out the cyclinders. For me I've used cylinder 3 and then worked balanced the others to that reference point (can't remember why i chose #3) ..but have always wondererd what the baseline suction value should be and if I'm close to that. Seems to run fine so I've never put any further testing or thought into it. (i hate maintenance and never look for more ways to spend time) Your procedure might be great way to get close if not right on. Also like your high rpm thoughts. Thanks for the tips .....renojohn (ps, hope what I say makes sense?)

radman · Apr 18, 2007

The actual vacumn reading (hg numbers) are less important than having even readings across the board. The HG reading will vary slightly depending on elevation anyway, but IIRC 240hg is the target. With idle speed reduced to 1000 rpm at 1/2 turn on the bleeds, you're at the perfect idle combo, and ready to start adjusting. Do anything to increase the idle speed by more than 100-200 rpm and you've made too large an adjustment at the shaft adjust screws-back off and start anew. Kind of a fail safe way to prevent getting carried away with any adjustments. It's not hard to find you've really messed up the numbers by chasing one tb that wants to keep getting "more". Doing it this way prevents messing up to the point where you have a really messed up synch on your hands. All adjustments should be made lightly, when it looks right, blip the throttle to see where it settles. Though you'll find the numbers tend to jump around a bit (you'll never see the exact same setting twice it seems), you can get pretty damn close using this method. The 1/2 turn is about where you'll find the perfect setting setting at.

RenoJohn · Apr 18, 2007

radman said:
.......... but IIRC 240hg is the target. With idle speed reduced to 1000 rpm at 1/2 turn on the bleeds, you're at the perfect idle combo, and ready to start adjusting. ...................... Kind of a fail safe way to prevent getting carried away with any adjustments. .................The 1/2 turn is about where you'll find the perfect setting settling at.

This makes perrect (common) sense and I'll be incorporating it into my future synch's. Nice that so easy to do on this bike. Thanks for the good thoughts and well spoken info. ...renojohn

painman · Apr 18, 2007

radman said:
The actual vacumn reading (hg numbers) are less important than having even readings across the board. The HG reading will vary slightly depending on elevation anyway, but IIRC 240hg is the target. With idle speed reduced to 1000 rpm at 1/2 turn on the bleeds, you're at the perfect idle combo, and ready to start adjusting. Do anything to increase the idle speed by more than 100-200 rpm and you've made too large an adjustment at the shaft adjust screws-back off and start anew. Kind of a fail safe way to prevent getting carried away with any adjustments. It's not hard to find you've really messed up the numbers by chasing one tb that wants to keep getting "more". Doing it this way prevents messing up to the point where you have a really messed up synch on your hands. All adjustments should be made lightly, when it looks right, blip the throttle to see where it settles. Though you'll find the numbers tend to jump around a bit (you'll never see the exact same setting twice it seems), you can get pretty damn close using this method. The 1/2 turn is about where you'll find the perfect setting setting at.

This is some great advice and my only question is how does the stock turnout numbers of the bleed screws compare with the 1/2 turn you suggest? And, are the throttle plate screws located near each throttle body? Getting ready to do my first TB tuneup. PM. <><

radman · Apr 18, 2007

There are 3 screws that adjust the actual throttle openings-1 joins 1 and 2, located between them , 1 joins 3 and 4, also located between them, and 1 connects 1-2 to 3-4, the engine must be turned off and the throttle opened wide to locate, it's right at the cable connection. I use my VistaCruise to hold the throttle open to locate and turn the the screw-if you do this, be sure to release the Vista before the restart, guess how I know this can happen...

The 1-2 and 3-4 screws can be adjusted while the engine is running, but in pressing on them to turn, you can force the throttle open, beware

Try looking Here for more info. Was in a hurry, forgive the search highlighting.

Mississippi · Apr 19, 2007

Radman-

When you do your TBS as described above - do you unplug a couple of injectors to place a load upon the engine? I believe it was Jestal that came up with this idea, and I tried this the last time I did a TBS. It made the engine pretty smooth below 4000 rpm, but still had vibration above 4000. I went back and repeated the TBS at 5K (disconnecting a pair of injectors at a time). This made the bike a little "rougher" at low rpms, but very smooth a higher rpm. Was perfect for an IBA run.

I like the idea of setting all the bleed screws at 1/2 and using the throttle plate screws to get even readings to begin with.

Think I will try this next time.

I was mainly curious if you have tried the "unplug the injectors" method, and what you thought about it.

Thanks

Found Post for other method: https://www.fjrforum.com/forum//index.php?showtopic=7547

radman · Apr 19, 2007

Mississippi said:
Radman- When you do your TBS as described above - do you unplug a couple of injectors to place a load upon the engine? I believe it was Jestal that came up with this idea, and I tried this the last time I did a TBS. It made the engine pretty smooth below 4000 rpm, but still had vibration above 4000. I went back and repeated the TBS at 5K (disconnecting a pair of injectors at a time). This made the bike a little "rougher" at low rpms, but very smooth a higher rpm. Was perfect for an IBA run.

I like the idea of setting all the bleed screws at 1/2 and using the throttle plate screws to get even readings to begin with.

Think I will try this next time.

I was mainly curious if you have tried the "unplug the injectors" method, and what you thought about it.

Thanks

Found Post for other method: https://www.fjrforum.com/forum//index.php?showtopic=7547

I have, and honestly didn't find it made for any improvement over my method, just more screwing around. The method just loads the operating cylinders more, but they are already loaded to a degree, the engine cylinder pumping is creating a load, just not as much. I've also put the bike into 5th gear to create a load, again no discernible improvement in balance accuracy.

Nikk · Sep 9, 2007

In my limited experience I've learned the follow:

1. Be prepared to loose a vacuum cap, replacements are available at the auto parts store. Just get a variety pack one will fit.

2. I tried the 1/2 turn out and synch the throttle plates; then sync with the bleed valves. I lost margin on my throttle adjustment cable. I could get the bike to 1000 RPM but no more. When I returned #3 bleed valve to the factory setting I recovered my throttle margin. My lesson was don't mess with #3!!

3. TBS needs to be done, it makes a huge difference in smoothness!

-Nikk

ELP_JC · Sep 10, 2007

Nikk said:
2. I tried the 1/2 turn out and synch the throttle plates; then sync with the bleed valves. I lost margin on my throttle adjustment cable. I could get the bike to 1000 RPM but no more.

Try 3/4 then

. Doesn't really matter as long as you open ALL the same amount, AND you can adjust your idle speed as desired. The idle speed screw is just a 'master' air bleed; if maxed out, just open the bleeds more, and vice versa. Later.

JC

IRBR · Sep 10, 2007

I'm a little perplexed by this thread. I've known of carb sync's for years, but fuel injector sync's?

It's not in the manual for my '05 FJR. My mechanic informed me that no synchronization was necessary for EFI. And, my bike has a perfectly smooth idle after ~13000+ miles.

Why are you performing this procedure and on whose recommendations?

IRBR

rayban · Sep 10, 2007

IRBR said:
I'm a little perplexed by this thread. I've known of carb sync's for years, but fuel injector sync's?
It's not in the manual for my '05 FJR. My mechanic informed me that no synchronization was necessary for EFI. And, my bike has a perfectly smooth idle after ~13000+ miles.

Why are you performing this procedure and on whose recommendations?

IRBR

Um, if you read the service manual, I believe you'll find it listed at the 600 mile initial service. Perhaps you didn't ask it in a way the mechanic understood, because surely any certified Yamadog wrench would recognize that TBS is indeed a periodic service item. Pick up a copy of the shop manual.

IRBR · Sep 10, 2007

I was going to say that it's not in the owner's manual in the recommended maintenance section but I went and looked. That section does have a subsection on EFI Maintenance, and specifically uses the word "synchronization".

Other than oil and oil filter changes, I've always taken my bike to a dealership for maintenance so I never gave it any thought.

I appreciate your response.

Thanks,

IRBR

throttle body sync

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