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Carb slide sticks

  • Thread starter Thread starter Ilanidrac
  • Start date Start date
I

Ilanidrac

Guest
Hi all,

I have a 1979 GS550L and the two middle carb slides stick when they are closed (all the way down). I cant seem to find a reason why. I have tried all of the slides in the middle two barrels, and that's the only place any slide will stick in the closed position. Any ideas as to why it may be sticking? I have also cleaned the carbs out thinking maybe there was gunk in the middle two barrels.

When trying to unstick them, I actually would up breaking the piece the throttle cable goes in, right where the hole is for the barrel on the cable. Anybody have a P/N for that or know where I can possibly find another one?

Thanks for any help.
 
PM sent!

Anybody have any ideas on the slides in the two middle carbs sticking in the closed position?
 
Gonna open it all up again next weekend and check on the bodies. Ill let you know if I need them/what I find. I hope it isn't a huge problem. I also may have miraculously found that piece close by my house. Going to find out in a few hours for sure. Either way, please PM me with how much you would want for that throttle piece.

Thanks again! :)
 
When you cleaned them, did you let each carb soak for 24 hours in Berryman's or did you just spray it with carb cleaner? Did you really scrub the slides to ensure any old gunk was removed from them as well?
 
Sorry for looooong wait until a post.

I did soak the carbs in a dip for more than 24 hours. And they are super clean.

After really tearing everything down, it looks like this is the problem:

The main jets are tightened down enough where it appears to snag the carbs. Loosen the jet up, and it not longer sticks. But they are then too far out. Is there a spacer or something that i am missing? Also, is tehre an exploded view of these carbs online anywhere that I can look at?

Thanks for any tips
 
There is a very thick brass washer under each main jet. Are those present?
BikeBandit has blowups of the carbs. Or you could get the manual off BassCliff's website.
 
VMcarb-1.gif
 
I just took a look and it lists part 16 as an o-ring, which I did get the kit for. I don't see a washer anywhere.

The other problem is that it is only the middle two carbs that stick like this.

Any other ideas?
 
It sounds like the needle is getting too far into the tube and possibly locking up. You need to verify that the needles are the correct size, and that they are shimmed correctly on top. Non-stock, or improper needles might be too fat too far down the needle, and they don't fit into the tubes. Not having the right washer or shim set-up in the slide where the needle mounts might have the needle going too far down the tube, and again, hanging up.

The jet washer I don't think is an issue. The needle should never get far enough down to touch the main jet. It's there to meter fuel in to the tube, and the tube is there to interact with the needle and allow for different flow rates at different slide heights.
 
It sounds like the needle is getting too far into the tube and possibly locking up. You need to verify that the needles are the correct size, and that they are shimmed correctly on top. Non-stock, or improper needles might be too fat too far down the needle, and they don't fit into the tubes. Not having the right washer or shim set-up in the slide where the needle mounts might have the needle going too far down the tube, and again, hanging up.

The jet washer I don't think is an issue. The needle should never get far enough down to touch the main jet. It's there to meter fuel in to the tube, and the tube is there to interact with the needle and allow for different flow rates at different slide heights.

Vm carbs have adjustable needles and don't have shims

But, your idea is sound

I'd take the needles out of the sticking carbs and try the slides only to see if they still stick

Then, compare all the needles to see if they're the same. Set the needles with the clip in the middle slot and try again
 
I took everythign apart again this morning. I think I found the problem.

The main jets in the middle, where the needle actually seats, were bent pretty bad. With the jets from the end cabs in the middle, the slides closed as normal.

Going to replace all four of them. Here is a pic:

Bendneedlejet.jpg
 
Sorry for the really late reply lol.

Yea, i don't understand how it's even possible to bend this thing, but this one and one other are bend to hell. I almost can't believe I didnt notice it before.

So big questions is...where can I get some replacements? I will need at least two, but I can't seem to find anything online.

Any part numbers I can use or ideas?
 
I'd check the Parts for Sale

Then Sudco

There's some other carb part houses also
 
well i got some, but i don't know if they are for the 550... the ones i have are for the 750 and i know they are the same as the ones is the 850 and 1000, but the 550 i'm not for sure. if you want i'll just send you a few for free. you'll need to clean them because they will have a little varnish and gunk on them, and if you bike runs too rich then you won't be out anything.
 
i wound up finding some replacement, and the carbs no longer stick! That was totally the problem.

However, the bike will only rev with choke, and letting it idle it will die after about a minute of running.

The carbs were all soaked for 24 hrs, the air box is on, its stock jetting, new o-ring kit, new intake o-rings, etc. it feels like it may not be getting enough fuel?

Any idea on what I can try to get it going?
 
Where are all your adjustments?

The pilot FUEL screw, the one on the bottom, should be about 3/4 turn out from lightly seated (assuming stock airbox and exhaust).

The pilot AIR screw, the one on the side, should be about double that, or 1 1/2 turns.

The idle speed screw should obviously be in far enough to keep it running.

When the bike is warmed up, synchronize the carbs and tweak the air screws for highest idle speed.

.
 
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