Carb Sync

[Guest]

Attempted to do a vacuum carb sync tonight. Ran into some issues.

The start wasnt too bad. #2 was off a bit, but they were pretty close.


Got 1&2 matching and 3&4 matching but couldn't get them all to match.


Then something went wonky and #3 dropped way off:


It's acting like the vacuum hose was blocked but I didnt see anything like that. Any other ideas why it would suddenly do this?

At the moment looking at image #1 I'm wondering if I should have even bothered with it. *frustrated*

[cowboyup3371]

You need to be synching 2 to 3 first, then 1 to 3, and finally 4 to 3 as number 3 is your master carb.

[MAJikMARCer]

You need to be synching 2 to 3 first, then 1 to 3, and finally 4 to 3 as number 3 is your master carb.

Got it. Figures as the 2-3 adjuster is the most difficult one to get to. I need to double check the vacuum hoses to make sure there is no blockage.

[cowboyup3371]

Undo the throttle linkage and move it out of the way as you won't need it while synching them. Basscliff has the procedure on his site if I remember correctly

[dorkburger]

I just attempted my first synch a few weeks ago (gs1150). On my carbs, and i believe this is standard, the center 2 need to be synched first , then each outside one is synched. I have a factory manual , and it is explained there reasonably well. Also, im assuming you plugged the petcock vacuum hose?
I am certainly no expert, and would wait for more detailed advice...i found lots of threads on the subject.
Be patient. after finally getting mine right, i was rewarded with a much smoother running gs

[GateKeeper]

have a look here, this is my second time at syncing my carbs....I was just as good the first time, but had to redo because I thought the carbs were dirty and took them apart once again, but not dirty, a bad coil instead....

http://www.thegsresources.com/_forum/showpost.php?p=1897824&postcount=123

.

[Steve]

You say you lost vacuum in #3. Are you numbering the carbs correctly?

#1 is under your clutch hand, #4 is under your throttle hand.

I ask that because, if you number them backwards, your (incorrectly-numbered) #3 has the vacuum port for the petcock.

.

[ender22]

...
#3 has the vacuum port for the petcock.
...

I think you may have found my over sight in an unrelated problem. I installed a new on/off petcock and I realize I've left this vent open when it should goto the diaphram on the original petcock. Which is essentially closed... This could explain why i'm having problems tuning that carbs air screw to fuel screw setting.

[MAJikMARCer]

OK I'm going to retry tonight.

To answer a few questions and make sure I understand correctly.

Are you numbering the carbs correctly? - Yes. I was counting the left-side as #1, going to the right-side #4.

Also, im assuming you plugged the petcock vacuum hose? - Actually that's something I did NOT do. I did plug it with my thumb a couple times just to see what difference it would make but it seemed to make #3 go worse, but I think that's when I had already lost the vacuum that I was expecting so I'll inspect all the hoses tonight first and then give it another go.

Undo the throttle linkage and move it out of the way - I'll look into this. As I recall the issue had more to do with the angles being really tight there in the middle. I was on Basscliffs site, looking for info last night, but I may have missed it. There is a LOT of info on there to swim through.

I was using these instructions. I'm going to go look through my manual tonight. And do some further reading. I should have read a bit more before starting. This is why you are supposed to do your homework BEFORE class.

[MAJikMARCer]

SMoooooth

Well after reading the instructions this was a LOT easier. Kinda feel like a noob. Sorry for the noob mistakes.

Closing the tank vacuum tube and starting from the middle out made a tremendous difference and was SO much easier to do.

Removing the brass vacuum nipples from the intake boots was much more trouble than the actual sync.

Took it for a brief spin around the block and I was surprised at how much smoother it was. I didn't think it was that bad originally. nejeff can attest to how it sounded before. It wasn't terrible. It's great now. Well worth the effort.

Thanks again for your advice guys! Big success on this one!

[nejeff]

Well after reading the instructions this was a LOT easier. Kinda feel like a noob. Sorry for the noob mistakes.

Closing the tank vacuum tube and starting from the middle out made a tremendous difference and was SO much easier to do.

Removing the brass vacuum nipples from the intake boots was much more trouble than the actual sync.

Took it for a brief spin around the block and I was surprised at how much smoother it was. I didn't think it was that bad originally. nejeff can attest to how it sounded before. It wasn't terrible. It's great now. Well worth the effort.

Thanks again for your advice guys! Big success on this one!

No your right, it sounded pretty good before, now I bet it's even better! Sorry I gave you bad advise it seems, I have always done 1,2 then 3,4 then the middle adjuster

[MAJikMARCer]

No your right, it sounded pretty good before, now I bet it's even better! Sorry I gave you bad advise it seems, I have always done 1,2 then 3,4 then the middle adjuster

No dude, no worries. I owe you big time for letting me borrow your vacuum sync kit.