fast idle run

[eddie50clarke]

hi all
just taken carbs off gs 550 1982,give them a good clean,and put back on.

the bike was a nightmare to start before i cleaned them.

i put back on,filled the carbs with fuel(maybe a bit full because a little bit of fuel leaked out of the air filter seal).

and started the bike,started second time.

but the revs just raced up to 3-4 thousand so i hi the kill switch

kept starting it but the revs are very high

the throttle idle screw is all the way out nearly and air jets as per manual spec

any ideas what is causing this or how to remady it

cheers

ed

[bmac]

Carbs

HI, Checked linkage binding ( not likely) Idle screw turned in not out? Did you check the clamps for fastening properly. Sounds like air leak. Did you check the o'rings on the manifold boots on the head? Maybe, that would be the place to start (o'rings and or manifold boots). These become hard and brittle over time and the orings against the head surface crack and do not seal creating vaccum leak. (high idle, poor running). Bmac

[Larry D]

Did you bench sync them first ?

http://members.dslextreme.com/users/bikecliff/images/carb_sync_notes.html

[Nessism]

Most likely these...

[indyjoel]

hi same thing

cleaned the carbs, new orings all round, new intake boots

idle screw out all the way, air screw ( I think that is right) is in all the way (in our out two turns does the same thing.)

starts revs to 4K and stays there

board says air leak but I do not know where

[indyjoel]

grrrr

need to bench sync AGAIN!!!!

i tested my theory of high revs by adjusting the butterfly screws whilst on the bike all the way out effectivly closing the butterfly valve

this dropped the revs way down but I also managed to stuff up one of the screws (hopefully I can swap this with another one I have)

Does my butterfly screw loosening logic stack up or am I just dreaming?

[Steve]

By "butterfly screw", do you mean the ones between the carbs that are used to sync the carbs?

Use those sparingly to do your bench sync, then again to do your vacuum sync. Don't just go loosening them to adjust idle speed.

.

[Steve]

No, there are FOUR screws. (for four-cylinder bikes with the CV carbs)

THREE for carb sync and ONE master idle speed adjuster.

There is a sync screw near the throttle shaft between 1&2, another between 2&3 and a third between 3&4.
These are small, slotted adjusters with lock nuts.

The idle speed adjuster usually hangs below the carbs, between float bowls 2&3.
This is a larger knob that can be operated with your bare fingers.

.

[terrylee]

How are your boots on your airbox and is it well sealed, and what about your filter? Also did you check your throttle cable I just put carbs. back on my 450 and it was idling fast, just had to loose the cable a little and it was ok. terrylee

[indyjoel]

How are your boots on your airbox and is it well sealed, and what about your filter? Also did you check your throttle cable I just put carbs. back on my 450 and it was idling fast, just had to loose the cable a little and it was ok. terrylee

Hi I have tried to answer all questions below:

Brand new boots on the engine side with new orings, old ones on the airbox side, the filter is in and the box is sealed.

the throttle cable is off as is the choke cable.

When I backed right of the butterfly valve screws the bike revved down to a "normal" range but was running reall really bad (sturggling, lean type chug chug noise)

I tried to adjust the air screws but still could not get it right.

The "butterfly screw" I mean are the ones between the carbs that are used to sync the carbs?

I undid them on the bike only to prove my sanity that it was causing the high idle.

I only use them to do the bench sync and then a vaccum sync.

There are four screws
three carb sync and ONE master idle speed adjuster.

These are small, slotted adjusters with lock nuts (the one I stuffed).

The idle speed adjuster usually hangs below the carbs, between float bowls 2&3.

This is a larger knob that can be operated with your bare fingers.

Will take the carbs off tonight and bench sync them with a small paper clip this time.