Question on throttle body sync

[Ramarius]

I did a throttle body sync today and didn't touch the 1st screw as instructed on the how to. by the time it was close to being synced #'s 2, 3, and 4 were pretty much run in to the stop. # 1 still showed higher on the gauge but just barely. I just wanted to know if this is OK or if there is another underlying problem? How do you adjust #1 or know if it needs to be adjusted? I live at about 5200 ft above sea level if that matters. Any help would be greatly appreciated. Thanks


In its current tune it does seem to run a bit smoother, it wasn't that far out and I have no mods.

 

[Ssky0078]

I did a throttle body sync today and didn't touch the 1st screw as instructed on the how to. by the time it was close to being synced #'s 2, 3, and 4 were pretty much run in to the stop. # 1 still showed higher on the gauge but just barely. I just wanted to know if this is OK or if there is another underlying problem? How do you adjust #1 or know if it needs to be adjusted? I live at about 5200 ft above sea level if that matters. Any help would be greatly appreciated. Thanks


In its current tune it does seem to run a bit smoother, it wasn't that far out and I have no mods.

Depending on the instruction for your specific bike the 'set screw' is not touched (#3 on my Fz1).

You want to first set your idle between 1100 and 1300 rpm with the idle screw/knob on the side of the bike. I prefer 1250 as it gives me the smoothest idle.

Then you start adjusting the 3 screws until they are as close to equal as possible with up to 2mm of variance between them.

After you are done adjusting at idle you want to then adjust again at 4,000 (some say 5,000 rpm). This is your running speed and again you want this as smooth as possible, by getting all 4 within 2mm of the 'set screw' (#1 in your case). When I last did mine the 1st and 4th cylinder dropped down about 6mm off of my set cylinder (#3 in my case).

Make sure that you are doing this at around 170 degrees for the motor. If you are getting hotter than that you want to shut the bike off and run a shop fan till it cools back down again.

 

[Ramarius]

That's how I did the sync. I just wasn't sure about the screws being bottomed out when it was close to being done. Pretty even at 4000 rpm.

 

[iviyth0s]

Make sure that you are doing this at around 170 degrees for the motor. If you are getting hotter than that you want to shut the bike off and run a shop fan till it cools back down again.

How crucial is this?? It'd be a VERY narrow window of time since my bike barely gets that cold at speed and sitting it'll run right up to 200+-

 

[Ssky0078]

How crucial is this?? It'd be a VERY narrow window of time since my bike barely gets that cold at speed and sitting it'll run right up to 200+-

I took about 45 minutes because I kept having to turn the bike off and waiting for it to cool. I do not know how important it is.

 

[TownsendsFJR1300]

I did a throttle body sync today and didn't touch the 1st screw as instructed on the how to. by the time it was close to being synced #'s 2, 3, and 4 were pretty much run in to the stop. # 1 still showed higher on the gauge but just barely. I just wanted to know if this is OK or if there is another underlying problem? How do you adjust #1 or know if it needs to be adjusted? I live at about 5200 ft above sea level if that matters. Any help would be greatly appreciated. Thanks


In its current tune it does seem to run a bit smoother, it wasn't that far out and I have no mods.

I messed with my #1 screw years ago (before I checked the initial setting-duh) trying to get the overall vacuum at yamaha spec's (with a Morgan Carbtune). I couldn't get it to Yamaha spec's. The main thing is to get them even.

I ended up re-setting #1 screw to 3/4 turns out. Some further research indicated 3/4 to 1 turn out is fine. It runs really good at 3/4 so I didn't mess with it further.


**Now, to your question, if you turn #1 out (CC), approx 1/4 turn, it'll give your other 3 screws MORE ADJUSTMENT and they shouldn't be near bottomed out. Sync again as you did before...

Also, I strongly suggest checking the sync at 4,000 STEADY RPMs and adjusting accordingly. The #4 cylinder usually pulls harder than the rest.

You'll find you can get all four about even at 4 K RPM's and at idle. It will definitly help with any vibes.

If possible, get the LARGEST FAN possible if front of the header radiator, and set it to high. Especially fine tuning, the engine gets very warm, the fan does help...


Please post your results. :thumbup:

 

[iviyth0s]

I messed with my #1 screw years ago (before I checked the initial setting-duh) trying to get the overall vacuum at yamaha spec's (with a Morgan Carbtune). I couldn't get it to Yamaha spec's. The main thing is to get them even.

I ended up re-setting #1 screw to 3/4 turns out. Some further research indicated 3/4 to 1 turn out is fine. It runs really good at 3/4 so I didn't mess with it further.


**Now, to your question, if you turn #1 out (CC), approx 1/4 turn, it'll give your other 3 screws MORE ADJUSTMENT and they shouldn't be near bottomed out. Sync again as you did before...

Also, I strongly suggest checking the sync at 4,000 STEADY RPMs and adjusting accordingly. The #4 cylinder usually pulls harder than the rest.

You'll find you can get all four about even at 4 K RPM's and at idle. It will definitly help with any vibes.

If possible, get the LARGEST FAN possible if front of the header radiator, and set it to high. Especially fine tuning, the engine gets very warm, the fan does help...


Please post your results. :thumbup:

I'll have my dad just run a hose in front of the radiator when I eventually do this :squid:

I've not gone into the service manual yet but I'm confused...how are you syncing the throttle bodies for each cylinder, at two different rev ranges? Wouldn't setting them happy for one make them unhappy for the other? (again I've never looked into this so if there's 8 seperate adjustments or something and I'm just stupid, let me know)

 

[Ramarius]

I messed with my #1 screw years ago (before I checked the initial setting-duh) trying to get the overall vacuum at yamaha spec's (with a Morgan Carbtune). I couldn't get it to Yamaha spec's. The main thing is to get them even.

I ended up re-setting #1 screw to 3/4 turns out. Some further research indicated 3/4 to 1 turn out is fine. It runs really good at 3/4 so I didn't mess with it further.


**Now, to your question, if you turn #1 out (CC), approx 1/4 turn, it'll give your other 3 screws MORE ADJUSTMENT and they shouldn't be near bottomed out. Sync again as you did before...

Also, I strongly suggest checking the sync at 4,000 STEADY RPMs and adjusting accordingly. The #4 cylinder usually pulls harder than the rest.

You'll find you can get all four about even at 4 K RPM's and at idle. It will definitly help with any vibes.

If possible, get the LARGEST FAN possible if front of the header radiator, and set it to high. Especially fine tuning, the engine gets very warm, the fan does help...


Please post your results. :thumbup:

Thanks, I will post the results. It'll be a few days before I can work on it.

iviyth0s .... There are only 4 screws. From what I understand if you get them close at idle they should be close at 4000. If it's not close at 4000 you need to readjust. It is more important for them to be close at higher rpm than idle. Hopefully you spend more time there

 

[TownsendsFJR1300]

I've not gone into the service manual yet but I'm confused...how are you syncing the throttle bodies for each cylinder, at two different rev ranges? Wouldn't setting them happy for one make them unhappy for the other? (again I've never looked into this so if there's 8 seperate adjustments or something and I'm just stupid, let me know)

No, your not stupid....

Its not even in the manual about checking it at 4K RPM's.

Once you get beyond that throttle opening, the air screw sync really doesn't affect it. The bike has (like most in-line 4's), some buzz. Mine, when I got it, was really bad at 4,000 RPM,s (48-50MPH) and extremly annoying. Synced it at idle (it was with in spec's to start with but got it closer) but still very annoying.

Later, I checked it at 4K, where my buzziness was worst. The #4 cylinder, in three FZ's (I've done two other FZ6's((forum members)), mine also-3 total), ALL pulled a higher vacuum in #4 cylinder at 4k RPMS. Adjust, re-adjust, etc. Got them within 3 mms at 4k and at idle. Yamaha allows 10mm's out. As noted above, if their super close at 4k, they'll likely be well within spec at idle, perhaps even closer... Doing that got rid of easily 90% of my buzz...

BTW, there is one butterfly screw, with a spring on it, inbetween the TWO throttle bodies, DO NOT TOUCH IT. That adjuster simply adjusts the two separate throttle body shafts (and butterflys) to each other. **In the older bikes, with carbs, you would use those screws to adjust the butterflys for the same vacuum between the cylinders...

The actual syncing, at the "box on the left side of the bike, under the tank is adjusting with air screws, NOT ADJUSTING the butterflys..

Those air screws are EXTREMLY SENSATIVE. 1/8 of a turn or less can make a big difference.. You'll find adjusting one, changes the sync in the others. That's why its again, extremly important to have a 4 hose (vacuum) set up...

IMHO, I would invest in at least a cheap BOX FAN to put in front of the bike, and NOT USING running water over the radiator. Besides making a huge mess, with the fan running on high, is more realistic (air flow thru the radiator/over the headers, etc) when syncing.

 

[Ramarius]

I couldn't stand not going out and working on it. So, I backed out #1 a 1/4 and went to town on re-syncing. Turned out great.....I think it was really close after the first time. When I first got the bike, I thought it was smooth....no vibrations. It was nothing compared to now! It runs so smooth at 35mph in 3rd you can't hardly tell its running. I think it is even going to get a little better mileage......after this tank, (It raps quicker and its hard to not crack open the throttle) Only one problem with the whole thing. I'm going to end up with a ticket because it's so smooth I end up going faster than I intend to.:Sport:

 

[TownsendsFJR1300]

Excellent!!

Just out of curiosity, was #4 cylinder pulling any harder than the rest at 4,000 RPM's?

Also, about how many MM's (if its on your tool) did it vary when you checked it (BEFORE ADJUSTING) again at 4,000 RPM'?

 

[Carlos840]

Excellent!!

Just out of curiosity, was #4 cylinder pulling any harder than the rest at 4,000 RPM's?

Also, about how many MM's (if its on your tool) did it vary when you checked it (BEFORE ADJUSTING) again at 4,000 RPM'?

I did my sync recently and they were all perfect apart from number 4 hat was a tiny bit lower both at idle and at 4000rpm.
It took a very small amount of a turn to get number 4 aligned at idle and it was still perfect at 4000rpm.

I then did a friends sync last week (also and FZ6) and 1 and 4 were aligned with 2 and 3 significantly lower. once again it was pretty straight forward to sync them.

Not sure were this #4 pulling harder thing comes from but on the 2 bikes i synced i didn't see it.

 

[TownsendsFJR1300]

I did my sync recently and they were all perfect apart from number 4 hat was a tiny bit lower both at idle and at 4000rpm.
It took a very small amount of a turn to get number 4 aligned at idle and it was still perfect at 4000rpm.

I then did a friends sync last week (also and FZ6) and 1 and 4 were aligned with 2 and 3 significantly lower. once again it was pretty straight forward to sync them.

Not sure were this #4 pulling harder thing comes from but on the 2 bikes i synced i didn't see it.

Cool, thanks..

In my bikes I synced, it was the first time they'd been done from the factory...:thumbup:

 

[Ramarius]

When I ran it up to 4000 I only needed to adjust 2 and 3 a bit. But this was after my previous attempt at syncing. My tool doesn't show how far off by MM. On another note, I kinda lucked out. I didn't have to make my manometer. I was cleaning out an abandoned trailer on our property and there was a factory built one in it.....Mercury filled. All I had to do was change out the vacuum lines......talk about timing:rockon:


I appreciate all the help, This is an awesome resource

 

[TownsendsFJR1300]

When I ran it up to 4000 I only needed to adjust 2 and 3 a bit. But this was after my previous attempt at syncing. My tool doesn't show how far off by MM. On another note, I kinda lucked out. I didn't have to make my manometer. I was cleaning out an abandoned trailer on our property and there was a factory built one in it.....Mercury filled. All I had to do was change out the vacuum lines......talk about timing:rockon:


I appreciate all the help, This is an awesome resource

Cool.

Yep, that little bit of tweeking at 4,000 RPM's does make a difference. Enjoy!!!

 

[Carlos840]

Cool, thanks..

In my bikes I synced, it was the first time they'd been done from the factory...:thumbup:

The ones i did to, both had less than 6000 miles and no mention of sync in the service history.

 

[Ramarius]

Mine has about 2800 miles on it.

 

[iviyth0s]

So why do the throttle bodies lose sync?? Do the screws themselves slowly turn out of adjustment or something??

 

[trepetti]

So why do the throttle bodies lose sync?? Do the screws themselves slowly turn out of adjustment or something??

Normal wear and tear. As valve clearance changes, rings wear etc each cylinder reduces power output. But wear does not happen evenly so after time each cylinder needs to be adjusted so that it produces the same amount of power as the others. In reality, you are reducing the amount of power in the 3 best performing cylinders to match the output of the weakest one. So it is a de-tuning.

 

[TownsendsFJR1300]

Normal wear and tear. As valve clearance changes, rings wear etc each cylinder reduces power output. But wear does not happen evenly so after time each cylinder needs to be adjusted so that it produces the same amount of power as the others. In reality, you are reducing the amount of power in the 3 best performing cylinders to match the output of the weakest one. So it is a de-tuning.

I have to agree with 95% of the above. :thumbup:

What I don't agree with (IMO) is once your in the upper rev range, the sync really shouldn't make a difference as the butterflys are way open and the sync isn't affecting the performance..

And yes, the adjustment screws are EXTREMLY SENSATIVE and take very, very little movement to adjust and even less, super fine tuning. Yamaha allows 10mm difference between the cylinders.

Mine, before the sync was still inside specs (at least at idle), but getting as close as possible (in may case, about 3mm's) takes some patience and extra time. (with the Carbtune, I know EXACTLY what the differences are between the cylinders.

The next time I do a sync, just for measure, I'm going to put just a tiny dab of clear Marine silicone just on the edge of the screws and the throttle sync body (with the idea of preventing any un-wanted movement for vibration, etc of the screws). Obviously, any further syncs are still doable as the silicone will just be keeping slight pressure on the screws and keep them from moving. Obviously, the adjusting screwdriver will still work. :thumbup:

Each of those long, horizontal marks, inbetween, IS 10mm's