GS 550 running away

[JTGS850GL]

Just curious... Can you describe the method you used to bench sync and vacuum sync the carbs? What order did you sync them and what did you use to adjust them? Wondering if you properly used the #3 carb as your reference.

[gs550rebuildguy]

Followed bikcliff to the tee...

Luckily I have done many multi carb sets before
I backed off the idle screw all the way then I increased #3 to let a wire tie wire clear it. Then I set the other three to match it just clearing the wire as well.
Way before that I ran the bike to observe the cv's rising in unison as well.
Upon advice here I removed the mismatched cv springs and used the larger ones for all four carbs. Set the fuel mixture screws at 2 turns.
Bought the manometer gauges and connected the adaptor to "common" and set all four screws there to equal.
Then with each carb individually connected I adjusted the throttle screws to match the vacuum.
To be honest the valve shimming was more noticeable because I was pretty close already on the carbs.
The other three times I sprayed carb cleaner to hunt leaks I didn't even think to spray around the return springs. It is a very obvious change there.
since the carbs are coming off anyway I hit that area with o ring safe chain grease and for a brief time the leak went away and I had hot idle as good as cold idle around 1250.
I went for a 25 mile ride and it all makes sense... a little doggy around three thousand on the road and really comes on after four thousand rpms
Just like any other butterfly shaft leak I have ever had. I will say this is a silent leak though compared to some auto leaks I have seen.
I was about to devise a sealed smoke test where I was going to saran wrap the exhaust and air box and pump in smoke and that would have found it but the carb cleaner worked fine.(just have to spray it directly on the springs)
Tuesday the dealer is back open so I should have my carb seals for the throttles. Since the process here didn't say to look at them Im glad I ran across some other places that did.
I don't think the soak in berrimans ruined them I am thinking they may just not be there at all !

[gs550rebuildguy]

Where can I get new throttle shaft seals?

Where can I get new throttle shaft seals?
I found my leaks it is the throttle shaft seals
1981 gs 550 t vm 32 Mikuni
Thanks

[gs550rebuildguy]

Think I got what I need underway now

boats.net has the shaft seals and washers
maybe they will even fit when they arrive
has anybody had luck moving seals from a carb that seems ok

[gs550rebuildguy]

Question

What does everyone else do for throttle shaft seals for the gs 550T Mukinis? I think I got the right gaskets and o rings coming but their book said the middle two carbs seals are obsolete... really?
Who's the go to for that??

[gs550rebuildguy]

Still running at 4000

Ok this HAS to be a stummper.
I have new intake boots new o-rings all around
I have the throttle cable sitting loose
Screws are two turns out
Starts like a dream
Floats set to 28mm with a digital caliper
Carbs were soaked in Berrimans AND new butterfly shaft seals
Valves are set to .08 on all but one and it is .06
I inspected for cracks in the intake manifold its good.
I followed the over haul procedure on here
They are currently bench synced
I switched from the 92.5 mains to 112.5 and from 40 to 42.5 on the pilots
Nothing has really changed I can back the idle off all the way
I have 130 125 127 134 compression
SOMETHING fundamental must be staring me right in the face but i really dont know what it is
I pulled one spark plug wire at a time off and still idles at 3800

[gs550rebuildguy]

22 not 28mm

Ok so I made a mistake n set the floats at 28 mm not 22
going back on now we shall see

[gs550rebuildguy]

Idle good for a few seconds

I got it to idle normal
Then hooked up my sync gauges and back to 5 k idle
put the screw back in and still off to the races
At this point it may be going to the shop

[gs550rebuildguy]

my airbox boots are not very good

Question
If my airbox boots DO let it SOME air why cant i get the engine to slowdown with the butterfly valves closed??
I obviously cannot see them but my throttle springs seem very strong but this bike acts as if they get sucked open....
WIth new boots o rings etc its like I got a hole in my motor
I even took off one spark plug at a time no change
I took off a vac sync allen screw and it dropped 500 so 4500 is still not good
Anybody else have some tests i could try?
Carb cleaner has been done but hey every thing on the suction side is brand new

[gs550rebuildguy]

reading up

This morning I plan to remove the air filter and run a test
I am going to slowly block the hole for the air filter with a board
If that works I am off to get new airbox boots
Still don't fully explain why it wont shut down when the plates fully close but we will see since the air to the idle jet does need restriction maybe I am on the right track.
Kinda of like a rag in front of the ole Johnson outboard

[Chris G]

Is there a chance the needles are not seated, almost sound like it's under some acceleration on start up, I know you say the throttle cable is slack just a thought, can't say I know too much about these carbs.

[gs550rebuildguy]

throttle shaft seals

I got them via partzilla and the parent company on the bill came frrom boats.com
I called to be sure ...and they came no problem in a weeks time
HOWEVER even the shop cannot find where the air is guzzling from yet...
I did not replace the idle pilot plugs and they were a bit hard and the o rings i got here split for the idle screws split in half right away with a VERY gentle seating so may look at those again but the power balance is even across all four so still looking at it
I am going to buy new carbs im done with these...

[gs550rebuildguy]

possible hard pilot plug question

Does anybody know if the little black pilot plugs can cause high idle like i am having? mine were about the only things did not replace
The mechanic ahs been ALL over these and cannot find any evidence of a vacuum leak either
Also do the main jets require an o ring? some books show one mine had brass washers.
What is the correct idle jet I tried the ones from my kit and the ones that were on there.
The dle jet screws have little effect so we have them ad 2 and a half for now.

[gs550rebuildguy]

Plug role

What role does the black pilot jet rubber plug play??
I have bs 32's

[steveb922]

It blocks a circuit that is not used in this particular application. I forget precisely what the effect of a leak through the plug is, but it's not going to be beneficial. You should be able to get a set of plugs to your door for less than $10.