Carb sync needed? How can you tell?

[jczlsr]

I'm just days away from 10 day trip on my 2009 FZ6. I'm going through my maintenance check list and saw the carb sync "check-adjust" in the manual. My other two bikes are a Suzuki DR and Kawasaki KLR 650's which are both thumpers so carb sync was not a needed maintenance item. My FZ6 runs perfectly both at idle and at speed and usually gets 50-55 mpg so I'm wondering if there any symptom's of the carb's being out of sync? I would like to check and plan on ordering a SyncoPro carb tool but am just running out of time. I also don't want to screw up a perfectly running bike at the last minute. Is their any damage that can result to the engine if the carbs are out of sync?

 

[SweaterDude]

The FZ doesnt have carbs. It is fuel injected, so it would need a throttlebody sync instead.

How many miles are on the bike?
Has it ever been synced before, either by you or previous owner?

It probably doesn't NEED it, but it should run smoother if the TBs are in sync.

 

[Jblk9695]

A wiser person than me once said "If it ain't broke don't fix it."
If it's running as good as you say, just leave it alone and don't worry about it.
Have fun on your trip.

Jerry

 

[Erci]

A wiser person than me once said "If it ain't broke don't fix it."
If it's running as good as you say, just leave it alone and don't worry about it.
Have fun on your trip.

Jerry

+1! If you've got a lot of vibration, bouncing rpm at idle, hesitation.. sync it. If you've got none of the above, leave it alone.

 

[jczlsr]

Erci.....Thanks for mentioning the out of sync symptoms. I have none that you listed so it's going to go unchecked for now.

 

[iSteve]

I'm not one to be overly aggressive when it comes to maintenance. But because i own a sync tool and it only takes 10 maybe 15 minutes, I sync my bike every season. I never notice any problems before a sync, but after I do it I find it's smoother. But I wouldn't worry about it, if it was way off you would definitely notice.

 

[Erci]

I'm not one to be overly aggressive when it comes to maintenance. But because i own a sync tool and it only takes 10 maybe 15 minutes, I sync my bike every season. I never notice any problems before a sync, but after I do it I find it's smoother. But I wouldn't worry about it, if it was way off you would definitely notice.

I wonder if it's a bit easier on the FZ6, room-wise. It's far from easy on FZ1. Besides removing loads of bolts and lifting the tank, the hoses are very hard to get to and the sync screws are even harder to get to. :don'tknow:

 

[iSteve]

The 6 is just a matter of lifting the tank. The hoses are on both sides of the frame and the block with the adjustment screws are right out in the open.

I did it two days ago while my friend who has a Gladius was watching. He couldn't believe how easy it is.

 

[dxh24]

What's this "carb" you speak of?

 

[jczlsr]

I just checked the TB sync and both cylinders #2 and #3 were low. I brought them up level with #1 and #4 at idle speed. I did what some on the forum suggested and re-checked at 4000 rpm. #4 was much higher so I brought it down level with the others. However, when I re-checked at idle again, now #4 was lower. I attempted to bring all cylinders even at both rpm but just couldn't do it so I compromise a little at both but #4 is still high compared to the others. Is there a way to make all 4 cylinders even at both rpm's or is this normal for the FZ6? This is my first attempt at doing this so I'm not sure.

 

[FinalImpact]

If you have mirrors but can't see out of them - sync may help!

Before you sync, if you're running stock plugs AND they have more than 13,000 miles on them, replace them! And check the cap tension too. All these little things add up and make the mirrors useless, bars shake, and your butt sore!

 

[TownsendsFJR1300]

I just checked the TB sync and both cylinders #2 and #3 were low. I brought them up level with #1 and #4 at idle speed. I did what some on the forum suggested and re-checked at 4000 rpm. #4 was much higher so I brought it down level with the others. However, when I re-checked at idle again, now #4 was lower. I attempted to bring all cylinders even at both rpm but just couldn't do it so I compromise a little at both but #4 is still high compared to the others. Is there a way to make all 4 cylinders even at both rpm's or is this normal for the FZ6? This is my first attempt at doing this so I'm not sure.

I've synced several FZ6's and found all had #4 cylinder pull harder/higher (before the sync).

Yamaha gives you 10mm's on the gauge to be within spec's. Syncing at 4k helps reduce vibes at that RPM's (which is where mine was buzzing big time). I lean towards setting them even at 4k more so than idle but even with that, I'm within 3mm's at both idle and 4k. Make sure you do a good rev in between and hold the throttle very steady at 4k for a second or two to even out.

I also put a very large commercial fan in front of the header/radiator as super fine tuning does take a little bit of time as adjusting one screw changes the others slightly...

I can almost guarantee, if you had the Yamaha shop sync it, it be no where as close as when you do it... On my old FJR, they adjusted a BUTTERFLY SCREW, which is a BIG NO NO (same for the FZ). I discovered that after finding the white paint on the butterfly sync spring broke and the screw turned. I re-set the screw back and re-synced the bike with the air screw adjusters.

Just as a reminder, UN-LESS you've pulled your TB's apart, DO NOT ADJUST the CENTER BUTERFLY SCREW (with the spring under it). Use the air screws on the block only...

Bottom line, re your bike, you should be fine...

 

[FIZZER6]

I just checked the TB sync and both cylinders #2 and #3 were low. I brought them up level with #1 and #4 at idle speed. I did what some on the forum suggested and re-checked at 4000 rpm. #4 was much higher so I brought it down level with the others. However, when I re-checked at idle again, now #4 was lower. I attempted to bring all cylinders even at both rpm but just couldn't do it so I compromise a little at both but #4 is still high compared to the others. Is there a way to make all 4 cylinders even at both rpm's or is this normal for the FZ6? This is my first attempt at doing this so I'm not sure.

I thought my FZ6 ran great until I did the throttle body sync! It runs like a different bike when properly synced! :thumbup:

 

[jczlsr]

When I made the adjustments, I sync #2 to #1, #3 to #2 and #4 to #3. I thought about trying to sync #4 to #1 and then adjust the other two. Would this even matter? Just was trying to think through on how to bring down #4 at 4000rpm when it's level at idle. I also made and used a sync tool that has a gauge 2-3 times the length of the Motion Pro or Morgan sync tool. Since my homemade sync tool has a much larger scale, I was thinking the difference would be quite small if tested with the other two sync tools.

 

[sxty8goats]

I;ve had the 4 hose vacuum gauge set up for ages now and have yet to get around to doing it. Does anyone have a pic of the gave attached?

 

[TownsendsFJR1300]

When I made the adjustments, I sync #2 to #1, #3 to #2 and #4 to #3. I thought about trying to sync #4 to #1 and then adjust the other two. Would this even matter? Just was trying to think through on how to bring down #4 at 4000rpm when it's level at idle. I also made and used a sync tool that has a gauge 2-3 times the length of the Motion Pro or Morgan sync tool. Since my homemade sync tool has a much larger scale, I was thinking the difference would be quite small if tested with the other two sync tools.

To my knowledge (and experiance), it shouldn't matter which you do first or last. As pointed out earlier, you adjust one, it will affect another cylinder some. I've found moving about is expected, start with the worst, then bring the others in-line. It may take a little while (thus the fan) but IMHO, its worth it. As long as you use #1 as a baseline, you should be good.

If you run out of adjustment on # 3, 4 or 5, adjusting #1 out slightly (approx 1 turn is a good baseline).

I do have a Carbtune and can check the measurement to a MM and adjust accordingly without worrying about the accuracy of the tool.

It should be noted, that there is a VERY, VERY small constictor that goes in-line. This is basically to keep the fluids/cylinders dampened and from jumping and hopping about. I'd estimate this constictor is HALF the thickness of a sewing needle.

With the MPG's you were getting and if the vibes were not noticable, you were likely fine. I almost sold my bike as the vibes thru the seat at 4k were terrible!!. 90-95% of those vibes are gone...