GS 550 running away

[gs550rebuildguy]

I have a hard time starting this Bike no matter what
it takes a small shot of carbcleaner and im off and running
if I pull the choke out it revs ok and all cylinders heat up in about a minute
then it begins to go all over the map for rpms up to 5000 and then pretty much stays there
I have put kits in the carbs so new jets, pilot jets, idle screws, blew them out twice
was not sure if the idle mixture screws go spring, washer, o ring??
Clymer does not a show a pic of that screw
left carb idle screw is stuck but could live with that if the rest works for the other three its at two turns now anyways
There was one CV spring that was smaller than the other three is that the problem? are they sposed to be all the same I have extras?

I ran the bike directly off a bottle of gas and same issue
I have inspected the boots they look new and there is no change even if I loosen the hose clamps and rock the carbs and spray wd40 or use propane to look for leaks.
compression is 120 120 130 150
new plugs new dyna coil packs new wires new ignition new airbox new filter new number two carb vacuum hose
ran the engine with the airbox off just to see that all CVs play together
Carefully Bench synced the butterfly valves set the floats to 21 mm
If the head were cracked wouldn't the compression even be worse?
Not making any oil so it seems floats are good ones ..I shook em during the overhaul
left it on prime one night no gas rushing out so assuming new needle and seats working good.
after warmup no cleaner needed fires right up and is a runaway
I could check each carb by loosening the float drains
I set the Idle mixture Screws at 2 turns out tried 2 n a half to one n a half guess what still running away on me
It dogs out of power when I tried to go around the block
So far not even one foot traveled
there is NO rust in the fuel system I sucked open the vacuum line and got great flow and the new line is clear so if it ever leaks id see it.
I bought a petcock diaphragm but the off tank test yielded no difference yet
It makes no difference if the throttle or choke cables are even connected
all positions are as low as they go as is the idle speed setting
Anybody know what is wrong??
Way big thank you if I get back on the road
Ps the airbox is back on and till my filter arrives I have simulated it with a brand new sponge don't laugh to hard

[850 Combat]

The carburetors are not cleaned out and reassembled properly. Either read how to do it on this forum and do the complete job correctly (there isn't any need to replace jets), or mail them to Chef1366. You can find him in the services section on this list. Inexpensive high quality work.

[gs550rebuildguy]

thanks for the reply

So when I rebuilt them I blew every passage clean with compressed air and used fishing line it the little holes they are in my humble opinion ok

do you happened to know the "stack order" of the idle screw/?
I felt I was guessing as they just fall out of there
I put the spring first the washer next and the little o ring next

Also should all the upper vacuum springs match in size?? I just don't know

thank you in advance

[850 Combat]

You didn't provide enough information for a person to know what kind of motorcycle you have. There are three kinds of 550 carburetor that I know of. I'm assuming that you have a 1980 to 1982, in which case this should be representative of the parts involved. The 4 diaphragms and springs should be the same. The stack height of whatever you mean should be shown here. The O rings thata don't come in the useless rebuild kits are available at cycleorings.com. If these are not your carbs, you can navigate to the correct ones from here. The 1983 on 550 has odd 2 barrel carbs, but the parts fitch on this site should show them if you find your year and model.

I hope this helps.

[Jet-Lee]

I've got those dual-throat carbs. I have a similar issue and I'm cleaning and dipping the carbs later today.

The "stack order" for the idle mix screws is as follows; starting from the tip it should be o-ring, washer, spring.


A different screw, but the order is the same:

[850 Combat]

I've got those dual-throat carbs. I have a similar issue and I'm cleaning and dipping the carbs later today.

The "stack order" for the idle mix screws is as follows; starting from the tip it should be o-ring, washer, spring.


A different screw, but the order is the same:

I'm curious:

Does Robert Barr have an O Ring kit for your bike? Those were groundbreakingly fast 550s when they were introduced in 1983.

[Jet-Lee]

I'm curious:

Does Robert Barr have an O Ring kit for your bike? Those were groundbreakingly fast 550s when they were introduced in 1983.

I just bought his regular BS kit.

I'll likely have o-rings left over. Oh well. Haha

[gs550rebuildguy]

Thanks 1981 GS 550 T

Well I am embarrassed these are not your Johnson outboard triple carbs that's for sure.
Off they came again last night for a 100% rebuild there soaking right now
I found the choke o ring on one was bad and after reviewed the 850 pics up here for the 32s I missed all the choke stuff as far as cleaning goes.
I don't think I can get my screw out for the idle mixture and Im chicken to heat it maybe Ill live it it but after soaking Im betting the little o ring is not going to be in good shape
If I heat it well yeah
There will not be one old o ring left nor will there be any unpoked holes this time. Even redoing the fuel petcock diaphragm with clear hoses to boot.
There was a tip that positively made removal a snap...pull the battery box so you can move the air box around. Took about 20 minutes for the whole process and the carbs droped and then pulled right up and out.
I guess the rule of thumb is if your bike wont start without gummout or whatever you have NOT got ALL the passageways working yet. I know I skipped the choke circuts but those 850 pics show it all better than any book ever published all with like maybe ten words...stay tuned...no pun intended and thanks for the screw pic.
link for the carb teardown...simply awesome

http://www.thegsresources.com/gs_carbrebuild.htm

[850 Combat]

The parts book is often better than the manual. All the good parts vendors have it, too, so its always available on line. If you go on Bikecliff's site, there is a GS850 factory shop manual you can download. There is a good section in the back of that that shows how the CV carbs work, all the internal passages, etc. There may be a 550 manual there too. Good luck, and I hope that you enjoy the bike.

[gs550rebuildguy]

Ok heres the update carbs are gone through by the pictorial on here they start great
all new o rings for carbs and intake there spotless
I took off the tank and ran it on a bottle and had great idle until i notice i failed to plug the vaccume line and yes number two was cold...as soon as i put a golf tee in the line it runs away im gonna need an expert to weight in...i tried on n a half turns on idle two turns then three an a half turns it will run a 2800 at three n half turns yes the linkage is fully returning the cable is hangin loose and so is the choke
I sprayed wd 40 all over n no changes... would it be valves ?? I can check that next
so the way this goes ... start it it idles great and 60 seconds later up it goes to 5 k
while riding it a little clutch contact and its back down during the clutch and its not trying to take off with lots of power... on the road its great at all speeds
what lese is there?? pretty sure carbs good no vaccume leaks most engines rev up with a vaccume line open this is just the opposite

[gs550rebuildguy]

I also soaked the carbs in berrimans during the rebuild as well

[Nessism]

Check the carb rebuild tutorial and Newbie Mistakes thread linked in my signature. They should help you.

[gustovh]

Did you change out the O rings behind the carb mounts? If not that could be your problem.
V

[Steve]

I see there is at least partial success here, but thought I would offer my comments in blue.

I have a hard time starting this Bike no matter what
it takes a small shot of carbcleaner and im off and running
Put away the carb cleaner, starter spray, EVERYTHING ELSE. You need fixes, not Band-Aids.
if I pull the choke out it revs ok and all cylinders heat up in about a minute
then it begins to go all over the map for rpms up to 5000 and then pretty much stays there
Either the idle speed screw is set too high or you have a vacuum leak
I have put kits in the carbs so new jets, pilot jets, idle screws, blew them out twice
I you have the original parts, take the "kits" out, throw them away (you have already wasted your money, so it's not that much worse)
was not sure if the idle mixture screws go spring, washer, o ring??
The picture shown by Jet-Lee is correct.
Clymer does not a show a pic of that screw
left carb idle screw is stuck but could live with that if the rest works for the other three its at two turns now anyways
You can live with a bike that doesn't work well? There might not be much point in me continuing, but I will do it anyway.
There was one CV spring that was smaller than the other three is that the problem? are they sposed to be all the same I have extras?
They should all be the same, but that is not what is causing your problems now.

I ran the bike directly off a bottle of gas and same issue
That shows that the problem is not the tank or petcock
I have inspected the boots they look new and there is no change even if I loosen the hose clamps and rock the carbs and spray wd40 or use propane to look for leaks.
Did you remove the boots and inspect the O-RINGS?
compression is 120 120 130 150
new plugs new dyna coil packs new wires new ignition new airbox new filter new number two carb vacuum hose
ran the engine with the airbox off just to see that all CVs play together
It will idle OK with no airbox, but will fall flat on its face if you five it any throttle.
Carefully Bench synced the butterfly valves set the floats to 21 mm
Why not set them to the PROPER HEIGHT of 22.4 +/-1/0mm?
If the head were cracked wouldn't the compression even be worse?
Not necessarily. The crack might not be big enough to leak until the head gets hot.
Not making any oil so it seems floats are good ones ..I shook em during the overhaul
No idea how a bike would "make oil" or even what the floats have to do with that.
left it on prime one night no gas rushing out so assuming new needle and seats working good.
after warmup no cleaner needed fires right up and is a runaway
Shouldn't need cleaner at ANY time.
I could check each carb by loosening the float drains
That would only show that there is gas. Unless you measured how much came out of each one to show that they are all the same, that is all you will know.
I set the Idle mixture Screws at 2 turns out tried 2 n a half to one n a half guess what still running away on me
Most of us that rebuild carbs will start with the screws out 2 1/2 to 3 full turns out, then tune from there. Note that these are full 360-degree turns, not "flips" of the screwdriver, which are half-turns. The screws may end up in the 2 to 2 1/2 turn range, but the bike will start much easier if they are out a bit more, then tune to perfection.
It dogs out of power when I tried to go around the block
So far not even one foot traveled
Still have the airbox off? If so, then no surprise.
there is NO rust in the fuel system I sucked open the vacuum line and got great flow and the new line is clear so if it ever leaks id see it.
I bought a petcock diaphragm but the off tank test yielded no difference yet
It makes no difference if the throttle or choke cables are even connected
all positions are as low as they go as is the idle speed setting
Anybody know what is wrong??
Way big thank you if I get back on the road
Ps the airbox is back on and till my filter arrives I have simulated it with a brand new sponge don't laugh to hard
Not laughing, just scratching my head vigourously.

Well I am embarrassed these are not your Johnson outboard triple carbs that's for sure.
Good thing they are NOT. It is so much nicer to have the proper carbs.
Off they came again last night for a 100% rebuild there soaking right now
I found the choke o ring on one was bad and after reviewed the 850 pics up here for the 32s I missed all the choke stuff as far as cleaning goes.
Just goes to show how incomplete the "carb rebuild kits" are. If the parts were provided, you might have spent a few more minutes trying to figure out where they go.
I don't think I can get my screw out for the idle mixture and Im chicken to heat it maybe Ill live it it but after soaking Im betting the little o ring is not going to be in good shape
Yep, that little o-ring is going to make you wish you had taken it out BEFORE dipping the carb.
If I heat it well yeah
There will not be one old o ring left nor will there be any unpoked holes this time.
"Poking" holes is OK, but you can not reach far enough with your "poker" to clean out the rest of the passage. THAT is where the problems lie.
Even redoing the fuel petcock diaphragm with clear hoses to boot.
There was a tip that positively made removal a snap...pull the battery box so you can move the air box around. Took about 20 minutes for the whole process and the carbs droped and then pulled right up and out.
I guess the rule of thumb is if your bike wont start without gummout or whatever you have NOT got ALL the passageways working yet.
Once again, you should NEVER have to spray anything to get the enginen to start.
I know I skipped the choke circuts but those 850 pics show it all better than any book ever published all with like maybe ten words...stay tuned...no pun intended and thanks for the screw pic.
link for the carb teardown...simply awesome
http://www.thegsresources.com/gs_carbrebuild.htm

Ok heres the update carbs are gone through by the pictorial on here they start great
all new o rings for carbs and intake there spotless
I took off the tank and ran it on a bottle and had great idle until i notice i failed to plug the vaccume line and yes number two was cold...as soon as i put a golf tee in the line it runs away im gonna need an expert to weight in...i tried on n a half turns on idle two turns then three an a half turns it will run a 2800 at three n half turns yes the linkage is fully returning the cable is hangin loose and so is the choke
I sprayed wd 40 all over n no changes...
No surprises. WD-40 is perfect for use as a Water Dispersant (hence the "WD" in its name), but you apparently don't have any water on your engine to disperse.
would it be valves ?? I can check that next
Tight valves will make cold starting hard. It's even WORSE when the carbs are not clean, either.
so the way this goes ... start it it idles great and 60 seconds later up it goes to 5 k
Classic sign of an intake leak. I will bet that your o-rings on the intake boots have major gaps in them, just as shown on the cycleorings website.
while riding it a little clutch contact and its back down during the clutch and its not trying to take off with lots of power... on the road its great at all speeds
what lese is there?? pretty sure carbs good no vaccume leaks most engines rev up with a vaccume line open this is just the opposite
That is because you already have a leak, not plugging the vacuum port simply makes it too much of a leak to overcome.

.

I also soaked the carbs in berrimans during the rebuild as well
How long did you soak them? Since you KNOW you are having problems, and should soak them the full suiggested time of 24 hours.

It is my opinion that a valve adjustment, full-proper carb cleaning and intake boot o-ring replacement will take care of a LOT of your problem.

.

[gs550rebuildguy]

Thanks steve

Ok I need to post a clear update
All Carbs have new o rings and have been soaked 24 hrs
in berrimans I made the special tool as per the pictures in here
The carbs are so clean they glow
The intake manifold o rings are brand new and spotless surfaces
If there is a leak cant seem to locate it
I used the standard troubleshooting to find the leaks tried propane, wd40, and carb cleaner to isolate a leak but could not induce any rpm fluctuations
I tried rocking the carbs still no dice
If you were to ask me its like it starts with full floats and they suck dry
I know that is not the case because its got tons of power on the street
I may make a hose barb and clear hose for the float bowl drains to check for level
It starts fine on choke now too
I have no progress on the 5 k runup problem but the rest of the performance is stellar now
WHY am i running at 5 thousand ? at idle still after all this?
I DID get the idle screw out with a 16th inch drill bit and easy out