Tracer 900GT: Illustrated Guide to Syncing Throttle Bodies, or - how to pull off all your fairings.

[Wintersdark]

Ok!  There are lots of guides for this around, however, I find most are actually for an MT09, or older FJ09.  The actual procedure for syncing the throttle bodies is the same, but how to get to your throttle bodies varies.  In fact, the actual syncing of your throttle bodies is trivially easy, but the job is a fair bit of work because of how much there is to tear down to get to them.   So; here's my guide to doing that on the (in this case, 2019) Tracer 900 GT!

Getting Started: You'll only need minimal tools here, 4mm and 5mm allen keys, a small flathead screwdriver, a pair of needle nosed pliers, and a manometer.  I strongly recommend the Morgan Carbtune Pro from here:

Morgan Carbtune - carburetor synchronizer for balancing motorcycle carbs

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Carbtune motorcycle carburetor synchronizers;polycarbonate tool...

Edit: That link appears to be broken.  Here's a working one: https://www.carbtune.com/

 

 Put the bike on the centerstand, and remove the seat.  No pictures here, because lazy.  It's a bit easier to manhandle the tank around if it's not full of gas, too, but it's not the end of the world if it's mostly full.  Be careful of being RIGHT full, though, because you're going to be disconnecting the overflow, and if tipped too much it may leak out the overflow outlet.  Mine was probably 90% full because I'm impulsive and dumb, and it wasn't a problem at all.

Remove the side panels.  Each has three weird little Ikea Furniture Style Cam Screw Thingies.  Two on the front, one on the back.  Release the screws, pull the top of the panel outwards to release the plastic pushpin inside, and then pull the panel down to unhook it from the tab on the bottom.  Disconnect the indicator lead, and that's it.  Obviously, there's two of these panels  

Remove top tank trim: This plastic bit has two screws in the middle, and three of those stupid bodywork pins on each side.  Remove the screws, and use your 4mm allen driver or some other poky tool to push the center part of the pin in to release it, then you should be able to pull them right out.  Once all six pins and the two screws are out, you can just pop it off the tank cowlings.

Remove tank side cowlings: Note that the "scoop" and the lower inside panel are removed as a single unit.  Remove the two screws on top of the tank, and (on each inside panel) two screws, one regular bodywork pin on the front (just under the headlight) and one unique "phillips head" bodywork pin near the bottom.  This last is removed via a JIS screwdriver (or phillips, I guess), turning about a quarter turn counterclockwise and allowing the head to pop up.  Then it's pried off like the other bodywork pins.  It's reinstalled with a screwdriver, too, vs. the normal body pin method of popping the inner tab out.  Anyways, feed the signal indicator lead back through it's hole, and the whole inside panel/tank scoop unit will come off.  

 

 

To be continued!

 

 

 

 

Edited May 12, 2022 by Wintersdark
Fixing a broken link

[Wintersdark]

Remove the narrow side panels along the bottom of the tank: These are kind of entertaining.  See, there's a plastic pin at the front you need to pull out, and a screw at the back.... But in the middle?  Velcro!  Seriously.  So, remove the screw, pull the front outwards to release the pin, then pull the top of the panel midway along it's length away to release the velcro.  Then, there's another metal tab - you slide the whole panel (keeping the velcro detached) backwards and down a little bit.  See photos.  It's really easy, but... Weird.  Velcro.

Move the gas tank: The goal here is to release the gas tank, and rotate it 180 degrees, putting it on the tail of the bike.  Make sure you've got a blanket/towel/stuff on the tail to protect paint, plastics, and such from metal edges and possibly drips of gas.  First, you'll need to remove one screw on either side of the front of the tank, and two screws on the base (under the seat) to be able to move the tank.  I removed the tank protector pad (as it's not there in the photos) but this was unnecessary.  Just leave it on.  Once you can lift the tank, there are two drain hoses on the bottom that lead out down the left side of the engine.  This was probably the hardest part of the whole job for me, as my hands are huge and I couldn't get the tank up far... and being full of gas, it was heavy and hand-crushing.  Still, they're just basic hoses, just get your pliers on the clamps and pull them off.  Rotate the tank, put in on the bikes tail on a towel or whatever.  Be very careful about the fuel outlet and wiring still connected to the tank - there's plenty of hose/wire to do this, but you want to be sure you don't have the tank resting on the fuel pump outlet.  Breaking that would be a bad time. I propped mine up with a block of wood. 

Remove the airbox: Pull the ECU out from it's slot in the airbox about an inch or so.  There's squeeze release tabs on the underside of each connector, this lets you get a good grip on them.  Mine where tight and hard to remove.  Disconnect, pull the ECU out and CAREFULLY put it somewhere SAFE AND SECURE, for god's sake don't drop it.  Your bike is a brick without it.  Remove the tree mounting screws (sides and front) then loosen off the three hose clamps holding the intake boots onto the throttle bodies.  Do not fully remove the screws or it'll be a huge pain in the ass (ask me how I know), just loosen them.  Along the left side of the airbox is the crankcase breather tube.  Disconnect it, then start pulling the airbox up.  Be careful of the intake boots, they should just slide off the throttle bodies.  Don't pry at them, if they don't want to let go, make sure the clamps are loose and give them a wiggle.  Once you get the airbox coming up, there's a drain tube on the underside.  Pop it off with your needle nosed pliers, and you can lift the airbox out.

Once the airbox is removed, reconnect the ECU, and just keep it off to the side.  I used masking tape to tape it to the handlebars, but whatever, just so it's connected but not in the way.

Ok, we're almost ready to actually sync the throttle bodies!   To the next post!

[Wintersdark]

Remove the vacuum caps off the throttle body vacuum ports: A little wiggle with your needle nosed pliers, and they'll pop right off.  Easy as pie; don't drop them - they absolutely need to go back on when you're done.  They're here:

Note that the leftmost one is hiding behind that bracket.  

Connect your manometer/vacuum gauge:  One lead to each port.  Hang your manometer up where you can see it - the Carbtune Pro comes with a strap to hang it off a handlebar, but I prefer to hang it from the rafters in my garage so it's a little easier for me to read.  It does need to be upright and reasonably level, though, don't lay it down.  I marked each hose with different colored tape - this isn't really important, just be sure you know how they're connected and ideally connect them in order so it's pretty obvious what you need to adjust.  Start the bike up, and let it idle till it hits operating temp.  If using a Carbtune Pro, be sure to RTFM and use the restrictors to even out the readout, or the bars will bounce a lot.  Still usable, for sure, but it's a lot easier with the restrictors in the hoses.  

Sync your throttle bodies: Note that one of the three adjustment screws (just left of the marked vacuum ports) is painted white.  Mine is the leftmost (#1?) but it may be different on your bike.  This is the master it's determined on assembly by the "alternate method" below, and is the weakest cylinder - you need to de-tune the other cylinders to match this one.  So, DON'T TOUCH THE WHITE PAINTED SCREW.  Your objective here is to get the bouncy bars all as equal as possible.  The actual vacuum shown doesn't really matter, just that they are equal.  If you turn a screw clockwise, you'll cause that bar to go up; turn it counter clockwise and that bar will go down.  Very small turns have very big effects, after any turn (I recommend 1/8th of a turn increments) quickly rev the bike a couple times to get the new setting to settle in.  I find three quick half second revs does the job well.  Side note: This bike is *LOUD* when revved without the airbox on.  Holy cow.  Loud.  Even with the stock exhaust.  

The closer you can get them, the better.  Even small bits out can lead to excessive vibration, particularly around 5000rpm, and if it's really far out you'll start getting a rough idle.  

Alternative Method (what to do if you can't make the primary method work): (Thanks to @skipperT for this!) turn all the screws in clockwise until they gently seat.  This will cause each cylinder to pull the most vacuum it can.  Then, whichever cylinder pulls the least vacuum is your new master, and you turn the other two screws counterclockwise to decrease them until they all match. 

The goal of both of these methods is that you should have your weakest cylinder "wide open" (screwed all the way in) to achieve the maximum possible vacuum that's still balanced in each cylinder.     

 

 

(Green strap is Just In Case.  I've never dropped a tank, but I don't want there to be a first time)

 

Once you're all done, as they say in those repair manuals, "installation is the reverse of removal." 

• Remove your manometer
• Put the vacuum caps back on
• Reinstall the airbox - don't forget it's two breathers, and be careful with the intake boots
• Reinstall the ECU
• Replace the gas tank (don't forget the two drain hoses, and be careful of the fuel hose when twisting the tank back.)
• Replace the narrow side panels, this time sliding them up and forward to get those tabs into their slots, then press the velcro in. 
• Replace the scoops/inner panels, being sure to feed the indicator light wires back through their respective holes.
• Replace the top tank cover
• Replace the side covers, remembering of course to connect the indicators.
• Put the seat back on, and you're golden.  
• Enjoy your feelings of accomplishment.

Edited June 22, 2020 by Wintersdark
Corrections + add alternative method

[Wintersdark]

I definitely need to replace the bolts on my light bar. Man, did that chinesium ever rust.  Yikes.

 

[BBB]

Excellent guide @Wintersdark,  thanks for posting with great photos.

For the tank, I find that it easier to undo the two bolts at the rear, leave the two at the front and then you can pivot the tank forwards and upwards. Wedge a piece of wood in there and you have space to undo the vent hoses as well as pump wiring and fuel connector if you are fully removing the tank. The vent hoses are held by thin clamps that are easy to pinch with your fingers and then just pull downwards to remove.

[draco_1967]

This is great! I will have to do this soon. My bike has a little over 3k miles on it now, and it has a bit of vibration at 5k rpm that wasn't there before. 

[skipperT]

To anyone reading this, the ECM is NOT “calibrated” to the white paint marked throttle body. The standard TB adjustment screw is simply marked by the factory as a reference point because during manufacturing and initial setup, that’s the throttle butterfly that was measured to be the one that will allow the highest measurable amount of vacuum through the throttle plates at idle. Thus, this is the “standard” that you raise the vacuum level of the other 2 cylinders to match. 

...except when it’s not. There are some bikes out there that you can not sync properly using the painted TB as standard and then there’s an alternate procedure for dialing in the sync.

Just so people are aware.

nice write up, Winter.

-Skip

Edited May 19, 2020 by skipperT

[Wintersdark]

1 hour ago, skipperT said:

To anyone reading this, the ECM is NOT “calibrated” to the white paint marked throttle body. The standard TB adjustment screw is simply marked by the factory as a reference point because during manufacturing and initial setup, that’s the throttle butterfly that was measured to be the one that will allow the highest measurable amount of vacuum through the throttle plates at idle. Thus, this is the “standard” that you raise the vacuum level of the other 2 cylinders to match. 

...except when it’s not. There are some bikes out there that you can not sync properly using the painted TB as standard and then there’s an alternate procedure for dialing in the sync.

Just so people are aware.

nice write up, Winter.

-Skip

Fair enough; I was going by what I read with regards to the "master" TB; my knowledge of FI bikes is a lot more limited, as the vast majority of my experience is with carbed bikes.   I'm interested, then, what is the alternate procedure?  

Particularly because mine's pretty much at it's limit - the #1 cylinder is the marked one, but the #2 is raised as high as it can go (screw topped out, can decrease the vacuum, but not increase it further)  so this may be an issue in the future.

[Wintersdark]

8 hours ago, BBB said:

Excellent guide @Wintersdark,  thanks for posting with great photos.

For the tank, I find that it easier to undo the two bolts at the rear, leave the two at the front and then you can pivot the tank forwards and upwards. Wedge a piece of wood in there and you have space to undo the vent hoses as well as pump wiring and fuel connector if you are fully removing the tank. The vent hoses are held by thin clamps that are easy to pinch with your fingers and then just pull downwards to remove.

Yeah, if you're not looking to do the sync, this is a good way to get under there.  This is how I did it on MT07, but there's no way in hell I'd be able to get the vacuum ports caps off with the airbox still on, and definitely not hook up the manometer.  Not to mention how it'd be basically impossible to reach the adjustment screws, even with a 90 degree driver.  

I figure at that point - where you've got all the fairings off already, so the bulk of the work is done - you may as well just take the other two screws off, rotate the tank, and remove the airbox so you can just reach vacuum ports and adjustment screws directly.  Saving 10 minutes by just levering up the tank so you can fight in a tiny space seems counterproductive.  

[SortedGT]

Good write up and food for thought of future work. Don't know the mileage on your ride but, while you were there; that deep in; where you not tempted to replace the HT plugs and air filter too?

[Wintersdark]

2 minutes ago, SortedGT said:

Good write up and food for thought of future work. Don't know the mileage on your ride but, while you were there; that deep in; where you not tempted to replace the HT plugs and air filter too?

Nah, I bought my bike in late November, it's just got some 4500kms on it.  No need to get into plugs and filter, but yeah. Under normal circumstances, you may as well replace the air filter and plugs while you're in there.  

[keithu]

Excellent write up! And you see why I miss no opportunity to curse the soul of whoever designed the FJ/Tracer bodywork. If Greek legends were written today, I am sure that Sisyphus would be cursed to an eternity of removing Tracer bodywork, reinstalling it, and then removing it again over and over again because he always forgot to install one thing under all the panels. 

[BBB]

6 hours ago, Wintersdark said:

Yeah, if you're not looking to do the sync, this is a good way to get under there.  This is how I did it on MT07, but there's no way in hell I'd be able to get the vacuum ports caps off with the airbox still on, and definitely not hook up the manometer.  Not to mention how it'd be basically impossible to reach the adjustment screws, even with a 90 degree driver.  

I figure at that point - where you've got all the fairings off already, so the bulk of the work is done - you may as well just take the other two screws off, rotate the tank, and remove the airbox so you can just reach vacuum ports and adjustment screws directly.  Saving 10 minutes by just levering up the tank so you can fight in a tiny space seems counterproductive.  

Sorry, didn’t make myself clear. I was only referring to the bit where you said you had problems getting the vent hoses off. Of course you need to pull tank and airbox to do the synch.

[Wintersdark]

6 hours ago, keithu said:

Excellent write up! And you see why I miss no opportunity to curse the soul of whoever designed the FJ/Tracer bodywork. If Greek legends were written today, I am sure that Sisyphus would be cursed to an eternity of removing Tracer bodywork, reinstalling it, and then removing it again over and over again because he always forgot to install one thing under all the panels. 

Absolutely.  I've a HUGE history of forgetting something while reinstalling bodywork too, and was straight up paranoid about that this time around seeing what an insanely huge job it was to dig down the the TB's.  I basically utilized the entirety of my garage laying out every piece in order to reinstall, so I couldn't miss anything along the way.  Even then, I was double and triple checking everything.  Kept imagining forgetting to put the caps back on the vacuum ports or something moronic like that, and only noticing when I finally finished putting all the bodywork back on.  

Seriously, though, there's no reason for it to be as crazy as it is.  I swear it's way easier to do this on a straight up fully faired sportbike.

[skipperT]

22 hours ago, Wintersdark said:

Fair enough; I was going by what I read with regards to the "master" TB; my knowledge of FI bikes is a lot more limited, as the vast majority of my experience is with carbed bikes.   I'm interested, then, what is the alternate procedure?  

Particularly because mine's pretty much at it's limit - the #1 cylinder is the marked one, but the #2 is raised as high as it can go (screw topped out, can decrease the vacuum, but not increase it further)  so this may be an issue in the future.

The alternate procedure is to wind all 3 screws in gently until they are seated. Look at your sync gauge, and whichever number TB is pulling the most vacuum is your new standard. Wind out the other 2 screws to lower the vacuum until they are all equal. 
yamaha doesn’t always print this in every service manual, but’s it’s been used since the R6 came out back in 06 IIRC? I think that was the first model where Yamaha started using paint marks on the throttle bodies to designate a “standard”. 
-Skip