first time starting since carb rebuild/cleaning

[hikermikem]

OK, I heard ya.

The idea is close, but the sequence needs to change.

1. Do a vacuum sync, get all the levels where they are supposed to be.

2. NOW, do a fine-tuning of the mixture screws.

The reason I feel the order is important is that if one cylinder is basically closed off on the vacuum sync (really high vacuum level), it is basically not contributing to the overall running of the engine, and it won't matter how much you turn the mixture screw, it won't make any difference. Do the vacuum sync first so you know that each cylinder is contributing to the overall running, then you can see the difference that each mixture screw will make.

When adjusting the mix screws after the sync, is the end result they should all be at the same level ? I'm envisioning having one carb optimized at a certain vac level, while another (also optimized) is now at a different level. By optimized, I mean set to the highest vac level it can go.

Yes?

[Steve]

When adjusting the mix screws after the sync, is the end result they should all be at the same level ?

After the vacuum sync, all your vacuum levels will be basically the same. Yeah, the factory manual says to adjust the outer ones a little higher than the inner ones, but I don't know anybody that actually does that. Yeah, the levels will dance around a little bit with respect to each other, but the average heights will be consistent.

When you adjust the mixture screws, NONE of the butterflies are being moved, but ALL the cylinders are moving faster so ALL of the vacuum levels will move, pretty much the same amount and all at the same time. Stated another way, when doing a mixture adjustment, you will not see one vacuum level change and not the others.

I'm envisioning having one carb optimized at a certain vac level, while another (also optimized) is now at a different level.

After you do the vacuum sync, the only way to get one carb's vacuum level different from the others would be to re-adjust the sync screw. Once you have done the vacuum sync, leave the sync screws alone, only adjust the mixture screws. When the vacuum level changes due to mixture adjustment, ALL the vacuum levels will change.

.

[850GT_Rider]

After the vacuum sync, all your vacuum levels will be basically the same. Yeah, the factory manual says to adjust the outer ones a little higher than the inner ones, but I don't know anybody that actually does that. Yeah, the levels will dance around a little bit with respect to each other, but the average heights will be consistent.

When you adjust the mixture screws, NONE of the butterflies are being moved, but ALL the cylinders are moving faster so ALL of the vacuum levels will move, pretty much the same amount and all at the same time. Stated another way, when doing a mixture adjustment, you will not see one vacuum level change and not the others.


After you do the vacuum sync, the only way to get one carb's vacuum level different from the others would be to re-adjust the sync screw. Once you have done the vacuum sync, leave the sync screws alone, only adjust the mixture screws. When the vacuum level changes due to mixture adjustment, ALL the vacuum levels will change.

.

So, to re-state it for us fuzzy-headed ones.... We are following the principle and procedure of the highest-idle method, but using the VISUAL (vacuum level) in place of the AUDIBLE (listening to the rpm)?

You've found the vacuum method to be more precise?

[growler]

cannot wait to put these comments to work. is it 5 o'clock, yet?

thank you everyone, especially you steve.

[growler]

with my 82 gs850g(z) it appears i have a premuffler. so i'd be going for #2 and #3 to read approximately 1-2 cm Hg lower than #1 and #4?

if your experience has been that it doesn't matter, maybe i'll just make them level.

After the vacuum sync, all your vacuum levels will be basically the same. Yeah, the factory manual says to adjust the outer ones a little higher than the inner ones, but I don't know anybody that actually does that.

[GateKeeper]

and it will look like this......





joy of sync'd carbs

.

[mrbill5491]

I've never used the synch gage to set idle, but it does sound interesting.

So you essentially turn each mix screw (one-at-a-time) until you achieve the highest level of vacuum with each carb? Then synch the carbs to each other using the butterfly adjusters?

Is that pretty much it?

Like I said, I was experimenting with this too see what it did. Seemed to work for me. I would watch the vacuum levels and listen to the engine as well. I kept playing with it until I found that "sweet spot" for each carb and went on from there. Engine was idling really smooth. Though after reading Steve's comment on the procedure, that makes alot of sense as well. All I can say is try it and see what your outcome will be.

[mrbill5491]

So, to re-state it for us fuzzy-headed ones.... We are following the principle and procedure of the highest-idle method, but using the VISUAL (vacuum level) in place of the AUDIBLE (listening to the rpm)?

You've found the vacuum method to be more precise?

I used both RIDER. The vacuum method lets you know where the carbs are in relation to each other. Though remember I did the idle mixture first.

[growler]

gonna work on this today, and i'll post results. however, i don't have a morgan carbtune. i'll be working with this type of gauge. carbtune is on the list of things to eventually purchase.

[growler]

Well, I'll have to continue on this sync tomorrow. I don't think I'm using the gauges correctly. Anyway here's a video of progress.

http://youtu.be/zmTNqxlpSJQ

[chuck hahn]

Commented on your video.......the answer to your problem is that you need to use the valves in the lines to dampen the vacuum just untill the needles steady themselves..then your ready to make adjustments.

[londonboards]

Suppression Taps

On the sych tool I borrowed, it had these little taps on it. Way easier to see what's going on when the needles aren't bouncing all over the place.

https://www.youtube.com/watch?v=c-iHNyp1Lss

Greetings

[growler]

Got it. Ill put those valves on the lines today and adjust them. I'll post another video after thanks!

[growler]

Is it true with this type of gauge that it shouldn't matter necessarily where the gauge needles are measuring (as far as "normal", "late ignition", etc) and just focus on getting them equal with #1 and #4 just a tick higher than #2 and #3)?

[chuck hahn]

I go for all of them as close to each other as possible...but read a service manual to be 100% sure.