running on 3 Vacuum issue

[Recoush]

BassCliff
MY sincere apologies my thought was there was an existing thread :>)
There are many Similar threads but is can see where continuity can be an issue

Sorry this is a bit long, Running into issue with cylinder Number 3
Vacuum for cylinders on 1, 2, 4 are steady at 10 see photo
3 is around 5

Using the 4 gauge set (vacuum gauge) rather than the color tune

Tried swapping gauge 3 for 4 reads the same so not the gauge or Vac tubing
Pulled the Plugs and checked for Spark seems to be OK (maybe weak hard to see in daylight?) swapped plug 3 for plug 4 same reading

Adjusting the air screw 3 will either make it run wild (accelerate) or cut off so not air screw, May try swapping 3 for 4 o-ring not seating ?

Tried spraying carb and engine foam (thicker) on the boats and the area around did not notice any change in the reading

Ordered intake o rings from the link here so maybe that will solve the issue
Do Intake o-rings exist on the rubber version or do I need to order new boots?

Read that the butterfly maybe an issue thought the slides worked ok, (will check when, the O-Rings arrive?

plan to do a compression test next time I get a chance as some else mentioned
The other thing that bugs me is the 5 inch vacuum vs. 10 inch vacuum Should we be in the 20? range

One exception is a backfire at 3K-4K from either #3 or #4 guessing its number 3 :>) seems to run good in general
Any better ideas

 

[Recoush]

Figured it out
There are many things you need to do to SYNC you?re Carburetors
Among them if you can find them is too read them :>)
So I am going down my list of things to check

Remove pods does the slide follow the others Yep
Are all the since tubes tight and not leaking Yup
Already know the gauges are OK as reads the same Yup
Leaking intake o-rings maybe got them today from the person listed on GS resources that guy is fast think I ordered them Saturday and got the new intake screws sweet Highly Recommend

Humm I am missing something (over think) back to the Kiss
AHH no wait are you kidding me

The GS1000E had a vacuum Siphon petcock,
The Vacuum siphon for the gas fuel petcock was NOT Plugged.

Jammed a screw driver into the tubing and all 4 are almost the same
Might be 2 less but very close to the same higher reading
by the way their are two plug the one by 2-3 the other #4 Leave the #4 open length of tubing etc.

Hope this helps someone else

 

[Steve]

Glad you have it figured out, but I have a few questions from your first post.

Using the 4 gauge set (vacuum gauge) rather than the color tune

There is nothing wrong with using a set like that, but why would you consider a Colortune to sync the carbs?
The Colortune is for adjusting your fuel mixtures, not carb sync.

Tried swapping gauge 3 for 4 reads the same so not the gauge or Vac tubing

Good that you checked.

Did you by chance connect all four gauges to one souce (using a manifold) to verify that they all read the same? I believe this is recommended (required?) for analog gauges.

Pulled the Plugs and checked for Spark seems to be OK (maybe weak hard to see in daylight?) swapped plug 3 for plug 4 same reading

Changing spark plugs will not do anything to affect carb sync.

Adjusting the air screw 3 will either make it run wild (accelerate) or cut off so not air screw, May try swapping 3 for 4 o-ring not seating?

Adjusting the air screw will affect the mixture, but not the carb sync (vacuum level). You could even remove the air screw entirely without affecting your vacuum level. The vacuum level is measured after the slide, where the pilot mixture hole is very small.

Ordered intake o rings from the link here so maybe that will solve the issue

Do Intake o-rings exist on the rubber version or do I need to order new boots?

Not sure what "rubber version" you are talking about.

Your new sig says it's a '79 1000, that has bolt-on intake tubes and they definitely use o-rings.

Read that the butterfly maybe an issue thought the slides worked ok, (will check when, the O-Rings arrive?

What "butterfly"??? Your VM carbs don't have butterflies.

The other thing that bugs me is the 5 inch vacuum vs. 10 inch vacuum Should we be in the 20? range

The actual number does not really matter much. What does matter is that they are all the same.

What was your engine speed while doing the sync? A very low idle speed will yield low vacuum numbers.
Suzuki calls for 1500-2000 RPM while doing the sync, I have always done it closer to actual idle: 1200.

.

 

[Recoush]

Wow thanks for the Feedback

Sync the carbs yes all four vacuum gauges are to the individual carbs vac ports (screws removed and the adapter tubes) Installed (shiny brass tubes in photo)

Spark plug check was to see if bad plug or coil really hard to see spark (daylight shade)
Original setup (since have wired the hot wire to plugs and installed the Relay) really does seem to help have not rechecked to see if can see spark)

From reading the limited instruction thought the air screw affected vacuum. Guess no way to adjust, have to eliminate the leaks?

Will post a photo the carbs look like they are attached to the fuel inlet with rubber intakes black and look like rubber ( have not yet attacked this issue of changing the intake o-rings) (this maybe a late 78 version like Jan 79 ? some weird items keep finding

One problem experiencing with the 107.5 main is that can?t seem to eliminate the backfire. (4 air pods and two tip turned mufflers (Mac products) these are similar to stock as they use the original headers had to grind off the welds to remove stock mufflers)

Engine speed suggested was 1000 RPM so between 900-1050
Just barley running so I could hear the engine as I adjusted the bleed screws and the air screws (air is about 1-1/4 turn?s avg and the bleed (fuel screw bottom of carb about 1-1/2 turns)

Still get a backfire around 4K interesting about the 1200 RPM the GS article I used say high idle around 1000 rpm ?

 

[Recoush]

here is the pods carbs and intake ports you can see the vacuum screw

 

[Recoush]

Here is another setup (sorry thought was one like it)
the other photo shows the rubber boot better

 

[Recoush]

What you can?t see their is smaller band clamp

The VM are smashed into the rubber boot and secured with a thin band clamp (holds the carbs in place) the other end of the rubber boot to the head is secured by two Philip head screws

Bought the o-rings also new screws the news ones are (Allen head)

note the blue vacumm cap that was my source of a vacuum leak on number 3 cylinder the other open one later will be a vent tubing

Just love GS resources really a wealth of information here on this one website

let me know if this helps thier may still be a vacuum leak
have to remove the carbs and those intake boots ?
next up a compression test

 

[Big T]

You sync VMs by taking the tops of the carbs off and turning that screw in/out.

VMs sync best over 1500 rpm

You need to calibrate those gauges against a single source, they can be wildly inaccurate out of the box

You need to start over

Didn't you download the free service manual for your bike?

All of the procedures are explained there, with pictures

How many of the newbie mistakes have you made so far??????

http://www.thegsresources.com/_forum/showthread.php?t=171846&highlight=top+newbie+mistakes