85 GS550 Carb problems

[Daishi]

As in the title, it's an 85 GS550 with the siamese/double carbs or what have you. It is not mine - yet, but I am looking to purchase it for $400.

First off, when the bike is stone cold, it starts with some hesitation, and wants to die if you don't keep the throttle cracked. You can ride it around, and so long as you don't let completely off the throttle, it's very smooth throughout all the gears and the revs rise and fall without hesitation. It does not bog or gasp when snapping the throttle like it would under an intake leak.

Now, this is when it is cold. As the bike warms, the problems become more apparent. At the lower RPM range, there will be that signature lean hesitation when you snap the throttle, and it wants to die unless you keep it above 3k. If it does die on me, it is impossible to start until it's cooled off significantly.

The most I can get out of it when it is in this state is some sputtering when I work the throttle while starting it.


I noticed there was fuel dripping out of the left carb's (When sitting on the bike) intake boot. Now this says to me there's some kind of float issue going on, but I'm not sure if this would cause the afformentioned problems.

Supposedly, the carbs were worked on after sitting for many years by a 'friend.' There's also something odd going on with the idle adjustment screw. I have to turn it in all the way to make contact with the throttle shaft.

Is this bike worth persuing, or should I keep looking?

Thanks for looking, and any advice is appreciated.

[Nessism]

Rebuild the carbs. The archives has thousands of threads about this topic so I suggest you use the search function to learn more.

[Daishi]

I'm sorry if I'm asking a very dumb question, but the bike isn't mine yet.

I know the float is bad, but I don't know if it is masking another problem. I was hoping someone with experience could go 'Yeah, the float is causing X, but Y has another cause.'

Basically just something to let me know if it's worth buying this motorcycle or if there's a good chance it'll turn into a money pit.

[Nessism]

I'm sorry if I'm asking a very dumb question, but the bike isn't mine yet.

I know the float is bad, but I don't know if it is masking another problem. I was hoping someone with experience could go 'Yeah, the float is causing X, but Y has another cause.'

Basically just something to let me know if it's worth buying this motorcycle or if there's a good chance it'll turn into a money pit.

It's a 25 year old motorcycle. If you don't enjoy fixing things and doing maintenance, get something newer that won't need as much work.

[67fire]

Having a bad day?
Daishi, he is normally a nice guy on here.

BTW,



Eric

[Danjal]

It might just be a bad needle valve also. It sounds to me like it might be running a tad rich, or the idle curcuit is plugged up. Also the rough idle could be cause by the fuel running out of the carbs.

For $400 id buy it and rebuild the carbs, pending the rest of the bike is solid. I just bougth a set off of ebay for $50, and thats the whole shebang... minus hoses. Being an older bike.. expect to do work on it to get it running, and id seriously do all the routine maintenence regardless of mileage or what you're told by the PO. Mines been in the garage for about a month now and thursday the tires come in.. then I finally get to go out and play. http://www.cycleorings.com/ is another good place to get intake and carb orings too. Cheap to boot and great service. While you have your carbs off Id suggest a new set to be on the safe side for about $7. You might thank yourself later for it too.

Id browse the forums for common problems and check those to your model. You might even get the guy to budge a bit. Just ask him if hes firm on price. You never know.

Best of luck to ya.

PS - check out Basscliff's signature or posts. He usually gives out the uber welcome with loads of carb info. He should pop his head in here sometime.

[robertbarr]

You have no baseline, and with a bike this old, there's a boatload of variables that will impact the way the engine runs. There simply isn't a single answer. If you didn't have a list of symptoms, it would be something of a miracle.

Look for BWRinger's baseline post for the 850 (it applies also to your bike). It's a concise listing of what you need to check. It's a long list, but not overwhelming at all.

[Calvin Blackmore]

gosh if the boots are airtight they should also be liquid tight.

Not sure how gas could leak out and air not infiltrate in.

bite the bullet and remove and clean the carbs replacing any defective parts along the way.

get robert barr's o-ring kit too cos the removal install is a PITA that you dont want to get overly good at via repeat performance.

[MelodicMetalGod]

As in the title, it's an 85 GS550 with the siamese/double carbs or what have you. It is not mine - yet, but I am looking to purchase it for $400.

First off, when the bike is stone cold, it starts with some hesitation, and wants to die if you don't keep the throttle cracked. You can ride it around, and so long as you don't let completely off the throttle, it's very smooth throughout all the gears and the revs rise and fall without hesitation. It does not bog or gasp when snapping the throttle like it would under an intake leak.

Now, this is when it is cold. As the bike warms, the problems become more apparent. At the lower RPM range, there will be that signature lean hesitation when you snap the throttle, and it wants to die unless you keep it above 3k. If it does die on me, it is impossible to start until it's cooled off significantly.

The most I can get out of it when it is in this state is some sputtering when I work the throttle while starting it.


I noticed there was fuel dripping out of the left carb's (When sitting on the bike) intake boot. Now this says to me there's some kind of float issue going on, but I'm not sure if this would cause the afformentioned problems.

Supposedly, the carbs were worked on after sitting for many years by a 'friend.' There's also something odd going on with the idle adjustment screw. I have to turn it in all the way to make contact with the throttle shaft.

Is this bike worth persuing, or should I keep looking?

Thanks for looking, and any advice is appreciated.

Welcome!

First off, check my sig for an owners group for our bikes.

As far as the symptoms your displaying, minus the dripping fuel, my bike was doing exactly the same when I first got it. Two bits of maintenance cleared it all right up: 1) Cleaning the carbs with meticulous attention to the idle and choke circuts and 2) Replacing the o-rings between the engine and intake boots.

Oh, my sig also has a link to the thread which I used as something of a journal for what I did to get my bike up and running.

Best of luck!

[Calvin Blackmore]

Welcome!

First off, check my sig for an owners group for our bikes.

As far as the symptoms your displaying, minus the dripping fuel, my bike was doing exactly the same when I first got it. Two bits of maintenance cleared it all right up: 1) Cleaning the carbs with meticulous attention to the idle and choke circuts and 2) Replacing the o-rings between the engine and intake boots.

Oh, my sig also has a link to the thread which I used as something of a journal for what I did to get my bike up and running.

Best of luck!

WOW ya know if not for the metal thing I would probably worship you!

[MelodicMetalGod]

WOW ya know if not for the metal thing I would probably worship you!

No worries. I have no use for worship, just send money.