Throttle Body Sync DIY

[FZ1inTX]

I recently had some issues getting my TB sync done and done correctly. After a long talk with Ivan about my woes, he provided me with a method to "start over" which paid off in dividends and for this, I am thankful. He's recommended I share this with you as it may help you all down the road.

If you know about the sync and have the manual, it tells you some basics but not enough. First thing it mentions is a magical (and almost unattainable!) 225 mmHG for a vacuum reading. As many know, this is nearly impossible and you'll mess up the bike trying. Long ago, I sync'd and didn't shoot for 225, I just balanced them based on the #3 cylinder. I believe it was in the 265 range. The Morgan Carbtune Pro is based on cmHG so it was 26.5. Two more things... the manual says nothing about any recommended temperature NOR does it say anything at all about RPMs.

So this time, I made the mistake of trying for 22.5. All four screws were nearly backed all the way out and still, 24.5 was about as close as I could get. The bike ran like CRAP. I could not get the idle below 1600 with the idle screw backed all the way off! I tried twice more and gave up yesterday. I posted my woes and Ivan answered for me. After a long chat, about this and other things, I was set to start over this morning. 20 minutes under the tank was all it took. So I'd like to share this with you.

First, IGNORE the magical 22.5 mmHG recommended setting... forget it! What is important is to balance all four throttle bodies no matter the number.

I'm adding this also after I wrote these instructions. These were written when I messed up all four settings. If you have never touched screws #2 & #3, do NOT seat any of the screws, skip steps 3 & 4 and move on.

Here's what Ivan told me to do and you will not find this in a service manual:

1. Set your idle for 1250 - 1350 RPMs.
2. Hook up your vacuum gauge device after lifting the tank and propping up (I use a piece of scrap wood cut to fit between the top triple/handlebars and the lip of the tank)
3. Turn all four brass set-screws IN to full lock for cylinders 1 through 4
4. Back out all four screws exactly 2 full turns.
5. Balance #2 & #3 by using the screw in the middle of those two throttle bodies as you look straight down. Correct, *not* the brass screws! This is the spring throttle linkage you will be turning. Go small increments as it rapidly changes.
6. Turn this spring-loaded screw gently in each direction until you achieve a balance on the gauge.
7. Once #2 & #3 are balanced, use the brass screws for #1 then #4 to balance them with #2 & 3.
8. Between each adjustment, give the throttle a slow nudge and slowly back off. Don't BLIP and let go.
9. Once balanced, bring it to about 4k RPM then slowly back to idle and check the sync.
10. If all is well, set the idle for 1250 - 1350 RPMs and put the bike back together.

This advice, as I said, isn't written anywhere and worked perfectly. Without Ivan's guidance, I'd be still likely doing battle with this and frustrated beyond belief. I cannot tell you how easy this method was and since you don't really have to mess with the brass screws for #2 & #3, 1 and 4 are the easier two screws to reach and see.

I'm going to do Michele's FZ1 when I have some more time and I'll update this with instructional photos and highlights/arrows in them. I really hope this helps out some of you the way Ivan helped me out because this can be seriously frustrating. I do not understand why the manual doesn't have these instructions. I'd have NEVER touched #2 or #3 at all and been done Saturday.

So why was my bike idling so high with no adjustment left? Ivan had two reasons, one was I had pinched something in that area and the idle screw couldn't seat to metal OR, I had too much air in the system. Nothing was in the way of the pulley or idle screw... so it was too much air. Because I'd had those screws backed out so far, it was a constant vacuum leak and the brass screws were doing nothing, just bleeding in a TON of air. This is why the bike was crazy with idle. All my own fault but I'm putting some blame on the service manual for not providing clear instructions.

She's spot-on now and I have idle adjustment room. I hope this helps someone out because I was not having fun at all. After idle, the bike ran like Usain Bolt seeking a Gold... faster than it ever had. Stunning on the road, shite at any one stop. No more!

 

[Erci]

Very interesting!! I thought TB sync was a huge PITA when I did it, but I used brass screws (never touching #3). Will try this approach next time!

If I'm not mistaken, Yamaha allows for a variance of 10 points meaning, if one is at 225 and the other is at 235, it is considered acceptable. Most people will be able to do much better than that, because it's their bike and they'll take the extra time to get the numbers closer to each other.

 

[T84A]

Ivan's the best. I'm actually taking my bike to his shop on Wednesday to get my FI worked on.

 

[FZ1inTX]

Very interesting!! I thought TB sync was a huge PITA when I did it, but I used brass screws (never touching #3). Will try this approach next time!

If I'm not mistaken, Yamaha allows for a variance of 10 points meaning, if one is at 225 and the other is at 235, it is considered acceptable. Most people will be able to do much better than that, because it's their bike and they'll take the extra time to get the numbers closer to each other.

I ran out of room for adjustment LONG before ever reaching even 25 cmHG and trying to achieve anything much lower resulted in the screws backed out too far which caused the constant leak. With 2 & 3 set at 2 full turns, then using Ivan's suggested method, I was able to hit 25.5 to 26 on the Morgan Carbtune Pro with room for adjustment. Maybe with some more work, I could get it lower but she's running great right now. I have a thought for her bike which is to come out 2.5 turns on #'s 2 & 3 which might get me to 24 but beyond that, I didn't care for the way the bike ran/idled. I believe Ivan is right when he says it's more important they are balanced regardless of the numbers but keep in mind, you don't want them balanced at an extreme high or low, hence the 2 full turns. This gives you an adjustment range of 2 full turns in either direction.

For reference, screwing it INWARD raises the reading in the gauge of choice which means screwing it OUTWARD will lower the values. If you go too far and pop that brass screw out, you're likely in for a long hard process to get it back in so be careful and know exactly how many turns you've done. Mark a piece of paper next to you with each adjustment.

This was much faster and very accurate.

Should I start the DIY pictorial from scratch? Meaning, removal of the screws to lift the tank? Also considered trying the produce a video of the process and editing it together.... but some of the stuff would be very difficult to video and will be very hard to photograph regardless.

 

[Erci]

Tutorial starting with lifting the tank is probably overkill, but on the other hand it would be nice to have entire procedure from start to finish in one place.

One thing I'd like to add, when it comes to lifting the tank and making this job easier. I found it difficult to get the screwdriver positioned correctly and even to just be able to see the screws when I just tilted the tank back. I ended up taking out the rear tank bolt as well and suspending the entire thing using tie-downs. Lifted quite high upfront and about 5" in the back, I could look from behind the tank to spot the screws and position the screwdriver.

Video of the procedure would be awesome.. you'll need help though.

 

[FZ1inTX]

Added a bold and valid point above in case you're still at the OEM settings. Seating the screws and backing them out two full turns is only valid if you've previously messed with those before. If this is your first sync, your job just became a lot easier!!

 

[CrazyBiker]

LOL, I figured out the fully locking them in and backing out 1 turn tip by myself after chasing this issue. Basically START FROM SCRATCH for your peace of mind.

Here is my thread elaborating my syncing woes:

TB Sync - High Idle Issue - FZ1OA Message Board

 

[vandal_xx]

Sync was easy, well I didn't actually do it, Eric did. Using a carb tune and the methods fz1inNH has stated works great!! Bike runs better. Might be a placebo, but I think I have a little bit more power in the mid range.
Thanks FZ1inNH

 

[goerion]

Still curious to see pictures off the springloaded screws on contrary too the brass ones. I've seen pictures of tuning the throttle bodies where they adjusted the brass ones. Would be very grateful
The simpler the better off course.

 

[fz1uk]

Did the step by step pictures ever get added? tempted to do this to mine as its running very rough at the moment and I'm trying to eliminate options

 

[Ahteef]

I followed the instructions, hooked up the sync and found that the center screw was moving 1&3 and not 2&3?? All lines were hooked to the correct vacuum port. Also 2&4 were even on the sync but when adjusting the brass screws on those, I could not get 2&4 even with 1&3? I have a 2008 FZ1. I'm I doing something wrong?

 

[FZ1inTX]

We never did the pic tutorial, but I have this one pic from the other forum that says it all.

In the center circled in yellow is the screw you want to adjust #2 & #3 with. Once balanced, then you use the two outer brass screws to balance #1 & #4 with the other two. Be sure you have the vacuum hoses connected in the proper order. When capped with the connectors, they are 1&3 and 2&4, not 1, 2, 3 & 4.

Hope this helps!

 

[Ahteef]

Thanks FZ1inTX, but it was me who pulled a real boner...... I didn't remove the black plugs on the #2 & #4 hoses!! I thought that they were hollow!? Duh! I'll remove them today and reset everything and try again. I believe I'll have better results this time!

 

[Blue Flash]

Just wanted to say thanks for all this information! I'm new here, and was looking for sync information. In the process, I learned a lot and found what I needed. While I was in there , I put masking tape with numbers on the sync hoses, so I can quickly verify I have the right hoses when I connect the Carbtune!

 

[Coldwarc]

Hi all, I’ve been having issues with balancing my throttle body. I’m able to adjust 1 & 2 to match 3 which was never touched and is at 225mmHG. But only on cylinder 4 even with the adjustment screw seated all the way in i was only getting 200mmHG. Cylinder 1 adjustment screw is almost seated all the way in but 2 & 3 has plenty of room for adjustment, I’m wondering if i should lower cylinder 3 reading to have some adjustment for cylinder 4 or use FZ1inTX method?

With the current set up I am able to adjust idle but the bike isn’t idling great with a slight rev hang in the mid rpms

 

[Tipper2]

Zombie thread but thanks for posting this, it's a soon-to-be done job on my list.

 

[Coldwarc]

Hi all, I’ve been having issues with balancing my throttle body. I’m able to adjust 1 & 2 to match 3 which was never touched and is at 225mmHG. But only on cylinder 4 even with the adjustment screw seated all the way in i was only getting 200mmHG. Cylinder 1 adjustment screw is almost seated all the way in but 2 & 3 has plenty of room for adjustment, I’m wondering if i should lower cylinder 3 reading to have some adjustment for cylinder 4 or use FZ1inTX method?

With the current set up I am able to adjust idle but the bike isn’t idling great with a slight rev hang in the mid rpms

For those having the issue i have do check your vacuum lines. I had a leak in mine causing improper readings and also do ensure your thermowax unit is properly adjusted as it may also affect the readings

 

[FZ1riderNY]

So it's been a couple of days since I have last posted here, shame on me. Thank God this post was still available to look at!
This past weekend I decided that it was time to adjust my throttle bodies since the 09' now has 29,000 plus on it and it has
never been done. The bike has been running and sounding kind of harsh and raspy in the exhaust department.
I decided to do the right thing and contact Eric, my buddy and original poster on this topic. He, as always, was more than
helpful and generous with his time. He cleared up a few questions I had and passed along some hints and tips that Ivan had
imparted to him. It made the job so much easier all the way through.
I ran to Staples and picked up a Silver Fine Point Sharpie and marked each hose from the throttle bodies 1 through 4. That
made things easier to spot in the maze of hoses and wiring. I also labeled each hose coming from the Motion Pro Tool.
I bought a small pack of 1/8" to 1/8" Vacuum Connectors which are needed and not included with the tool. I first did the
mandatory calibration which was easy as pie. Once it was all level across the board I started the synching process.
With the bike at 140 degrees, I matched cylinders 2 and 3 together with the middle screw which faces upward at the
mid point of the throttle bodies. Cylinders 1 and 4 were so far off from each other I knew why the bike had been sounding
terrible. With a precision screwdriver I snaked my way through the hoses and found the adjustment screw. A few turns and
cylinder 1 was now in synch with 2 and 3. The #4 screw was a bear to reach but I finally got it while sitting on the clutch side
of the bike. After I had number 4 done I had to readjust 2 and 3 once again. Then once again with number 4. You can immediately
hear and feel the difference when they are all in synch. A couple of light blips on the throttle and I knew I was going to be
satisfied.
I used some 12" needle nose pliers to connect the hoses together again and put everything back together. It takes longer
to get everything installed again than to do the actual procedure. I took it for a quick rip up and down the street a few times
and was really pleased with the way it ran. A huge shout out to Eric for all the help. It was invaluable to me. The job wasn't at
all extremely difficult. I'd give it a 4 on a scale of 1 to 10.

 

[cannedSardina]

Are you all syncing everything with the air box off? I can’t see a way of accessing the 2&3 screw without it off. Worried that may throw the readings off?

Also, I just checked my sync (after 16yrs) and am getting all 4 readings between 26cmhg and 28cmhg. 2&3 are even. 4 is slightly lower than 2&3 and 1 is slightly higher than 2&3. Should I work to get that closer or is that fine?

It is hard to know exactly with the bike idling. They look all very close. But when I give it throttle to about 4’k as stated above they all even out and those above are the reading I get. When you sync them are you trying to get them synced at idle or at 4k when they stop bouncing?

Any info is great.

Thanks.

 

[jwarden]

Are you all syncing everything with the air box off? I can’t see a way of accessing the 2&3 screw without it off. Worried that may throw the readings off?

Also, I just checked my sync (after 16yrs) and am getting all 4 readings between 26cmhg and 28cmhg. 2&3 are even. 4 is slightly lower than 2&3 and 1 is slightly higher than 2&3. Should I work to get that closer or is that fine?

It is hard to know exactly with the bike idling. They look all very close. But when I give it throttle to about 4’k as stated above they all even out and those above are the reading I get. When you sync them are you trying to get them synced at idle or at 4k when they stop bouncing?

Any info is great.

Thanks.

It is for the idle setting. It is to have the air bleed around the throttle plates set the same at idle. When the throttle plates open this setting is effectively swamped out by all the air through the throttle bodies.

The service manual does state to blip the throttle after adjusting the screws to make sure it stays even across the cylinders. Tweak as needed.