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Throttle body synch


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img][img]Thought I would share my experience yesterday when I checked the throttle body synch on my 2015 FJ-09.  I did the 600 km service myself, but not the throttle body (TB) synch check/adjustment.  I then road my bike down to Boise Idaho from Lacombe, Alberta to visit my sister and brother-in-law.  The bike had around 1,400 km at the time and now has about 4,444 km.  
I was doing another oil change (I like to do these more frequently than recommmended in the owners manual) and thought I would check the TB and adjust if needed.
I have the factory service manual (FSM) and I reviewed several of the threads here as well as youtube videos.
In the FSM it gives pretty good directions and indicates the steps to follow in order.  The only thing is to be aware of some of the metal tabs with rubber tips on the panels, etc. when removing the plastic panels.  The metal tabs fit into plastic fittings on the panels.  Fortunately, I didn't break any of the plastic fittings.
Once I had access to the gas tank it self I removed all the necessary bolts.  I was then looking at either disconnecting the hoses or simply rotating the tank 180 degrees and placing it on the seat area with a towel and a block of wood as per some of the other threads.  
In the end I simply placed a Black and Decker folding work bench on the left side (when you are sitting on the bike).  It seemed to work very well and didn't appear to kink or twist any of the hoses too much.  I then worked on the airbox.  The airbox hose on the left was the first to be removed and then that allowed me to easily access the airbox vent hose on the right.  I used a set of long pliers with a right angle tip, which made it easy to grab a hold of the clamp and move it.  
Next came the removal of the rubber plugs on the vacuum ports on the TB.  The center and right were easy, while the left is kind of buried behind.  I used a flat bladed screw driver and gently pried the plugs up and then gently grabbed them with a set of long pliers with a straight long tip.  I was a bit concerned about the pliers perhaps cutting the caps, but I grabbed them gently an slowly removed the plugs with the small wire clamps still attached.  I also had a small magnetic reach tool ready in case I dropped one of the plugs.  With the small wire clamps attache I could at least use the magnetic tool. I think I will order an extra set of rubber plugs and the small wire clamps as a backup just in case.
Next came attaching the Motion Pro Synch tool (MPST).  I first attached it to the right TB (which was painted white BTW) and made sure the MPST was calibrated.  Next came attaching the hoses from the MPST to each of the TB's.  I only needed to use three of the hoses.  The centre and right ports were each to access and fit the tubes, while the left one was a bit more problematic, but I eventually worked the hose behind some of the other hose lines and started it on the vacuum port and then used a long nosed pliers and gently pressed it on completely.
I did the TB synch without putting the airbox back on as per some of the other threads.  
I had experience using the MPST on an old 1981 KZ650 I had. The only thing is how finicky getting the three TB's adjusted.  Unfortunately the middle TB screw was close to being fully seated and I couldn't adjust it, i.e. screw it in further.  This meant readjusting the white painted screw and then the other remaining TB's.  I tend to be anal and adjusted and re-adjusted the screws, while blipping the throttle 2-3 times and then checkeding the MPST.  I did this about 6-10 times.  Finally the three columns of fluid in the MPST for the three TB's were more or less even.  I then disconnected the MPST and started to reassemble the bike.  
At this point I was a bit stressed about getting the left TB vacuum plug back on.  It is in a tight spot.  I thought perhaps I could use a set of long nosed pliers, but was concerned about dropping the plug or perhaps ripping it.  I thought there must be a better way.  I then thought perhaps using a small socket (may be 8 mm) with a small socket wrench, might allow me to position the plugs and put them on. I would simply put the plug into the socket.  As I was looking at my sockets the 8 mm was too loose and the 7 mm was a bit tight.  I then thought what about a small wrench.  In the end a 1/4 in wrench was perfect.  I fitted the tip of the plug in the closed (circular) end of the wrench and then placed the plug (with the small wire clamp still on) on the left TB port.  Talk about easy.  The plug went on very easily and I fully seated the plug with my finger.  I then checked to make sure the small rubber wire clamp was in the right position and carefully adjusted with a flat bladed screw driver as needed.
I then finished up by putting the airbox box back on and placed the gas tank back on the frame.  The two vent hoses that go down the left side of the bike and been pulled up a bit so I made sure to gently pull them down to the correct position and checked so see that they were not kinked underneath the gas tank.
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thanks for the post! how did the bike run after the TBS?
The synch wasn't out by much to start with.  I took it out for a bit of a rip (ride) around Lacombe and Red Deer, Alberta including Highway 2 (speed limit is 110 km/hr, but most of the traffic goes 120-130 km/hr) and some city streets.  The bike did seem to run smoother.  My son has a 2015 FZ-09 in Edmonton and I can help him with the TB synch. 
I am still fiddling with the bloody chain tension and reading the threads on this site for the FJ-09 and on the FZ-09.  However, this isn't the topic of this thread LOL.
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One thing I found easier was just pivoting the tank up at the back leaving front mounts on, disconnecting lines and plug. Then remove tank.
Remove air box and fit vacuum gauges, refit tank leaving it raised at the rear pivoting off front mounts. Block of wood or rubber works well.
This way you have no chance of the tank slipping off the bike or kinking fuel lines or worse snapping the fittings off the pump... $$$
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The reference screw can be adjusted? My 2nd cylinder is also close to be fully seated but I was afraid to play with the reference.
The adjusting screw with the white paint mark is supposed to be standard. Except when it isn't, and then there is an alternative procedure which is documented in the service manual.
You can run all 3 of the screws IN fully to see the vacuum as the throttle body comes out of the factory. Just count the number of turns each one was set at so you can get them back OUT to the same setting before syncing. This is pretty much the alternative procedure. You then note which TB has the lowest vacuum (which should have the white paint mark but not always).
That is your reference TB. Sync the other 2 to the same level as the reference.
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Question about engine speed for sync: As I recall, the TBS procedure states to sync the throttle bodies at idle speed. Is it normal for the vacuum to be unbalanced at every other engine speed? I balanced mine at idle, then throttled it up to about 3000 rpm and they were all different. It seems to me that idle is the least sensible speed to sync the throttle bodies. Unless it won't idle otherwise. I think that your slowest cruising rpm would be a more sensible speed for syncing. Anyone else notice that? If it weren't such a hassle to re-sync then I would test that theory.

2015 red FJ-09: Cal Sci screen, Sargent seat, ECU flash, slider combo, cruise, Rizoma bars, Matts forks, JRi shock, slipper clutch

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I've wondered about that for years.
Yes, what you are saying makes total sense. Why are we so concerned about syncing at idle when 100% of our riding is at other throttle positions?
My FJ exhibits the same behavior you noticed, and just about every other mcy I have observed does the same thing.
My guess is that it's "close enough".
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I noticed the same pattern when I synched the TB's. At idle they were even and then when you blipped the throttle as per the FSM procedure the columns of fluid in the Motion Pro gauge were not the same. However, when the bike returned to idle they were even again.
Interesting question.
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We have always been taught to sync at idle, I suppose the reasoning is that the cylinders should all have near to equal compression etc and SHOULD be pulling the same vacuum readings... But this is rarely the case. I had a 2000 model gsxr600 that the fsm called for balancing at 3000rpm. Had to get that done quickly to not piss off the neighbors!!
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  • 3 weeks later...
Whilst you have the bike apart, why not make up some remote tubes that allow you to check the sync without pulling the tank. At least you will be able to do a quick check without going to all the hassle.
That is exactly what i plan on doing I had made some tubes up for my 82 gs1100e for the 4 carbs, made it alot easier to attach the hoses too, alot less to take off too
i just got my cruise kit, so i will be doing both that and the sync in a few days
if only i could rig up 3 separate adjusters to adjust as needed too
also on my gs and my s2a 350 tripple i did hold the throttle at 2500 while adjusting
but those are both carbed not tb
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