Hey all,
my GS has been great, up until a few days ago. Lots of reading ahead, so here I go:
So normally, I'm able to start the bike without any choke at all, just give the throttle a few twists while starting, and she idles at about 1k for a minute, before climbing to 1.2k. Then I'm off, and its got lots of power.
But two days ago, this was not the case. I tried to start it like I normally do, and nothing. I thought, fine, its been sitting for two weeks, I'll give it some choke. It started after a few turnovers, with full choke, but the idle was all over the place! I mean, up to 3k, down to 1k, and up to around 2.5k, slowly moving around that range, unpredictably. I let it idle for a few minutes, slowly backing off the choke, and I finally got it to idle with the choke off. Now, the next problem.
I gave it some aggressive throttle inputs, and it died. It felt like when you flood the carbs with throttle, while its on choke. I then applied very gradual throttle, but I wasn't able to get it past 4k until it started to die. I rode it for a bit, and the bike had almost no power. After 5 minutes of riding, the problem went away.
I got home, and drained each carb. Not sure how much I was supposed to, but I let each one drain for about 20 seconds.

So tonight, I went to fire her up again. Same problem!
Crazy sporadic idle on choke, dies with slightly aggressive throttle, and wont go past 4k. Weird thing though, when I sat the bike upright, the idle climbed to 3k, and held it somewhat steadily.
But this time, the problem went away after only a minute of riding. After that it pulled hard, with very aggressive throttle.


Its a '94, with ~48 000 KMs
Full choke is normally 4k
A bit of fuel thats in there has been since about may... 2L maybe
Oil Changed in may, almost no mileage on the bike since then
I normally take it out for a 10 minutes or so, just so it doesn't sit. But other than that, very little use.
Lately, weather has been about 15 Celsius during the day.

It could be the fuel, but I've been running on that bit for a while, and its long since been diluted with new fuel.
That 4k throttle limit really makes me think it could be my pilot jets. Maybe some crap was built up in them from the fuel? But why would the problem go away?
I also read a forum post about new oil having some good effects. I have a big bottle of semi-synthetic and a new oil filter that I'll put in if I need to. I'd just rather not, unnecessarily.
I doubt its the plugs or coil, since the problem goes away. Or at least seems to.

I am confuse. Some guidance would be much appreciated.
Thanks in advance, guys.

Well, since no one else answered, I'll just put up some thoughts.

The problem goes away after riding for some period of time, so that makes me think it is temperature dependent.  Maybe there is a vacuum leak that closes up when it gets warm? 

Check all the screws on the carbs, check for vacuum leaks when cold, maybe check float height too (before starting it up cold). 

When was the last valve clearance check?

Thanks for the reply.

Which vacuum lines should I be checking and do you have a link to float adjustment? Should I just take the carbs out, so that I can check all the screws?

I figure, since the riding season is almost at an end, I may just rebuild my carbs, and do a valve readjustment. I have no idea when the last one was done, and I was planning on doing it soon anyways. Since the bike will be out of commission, what else should I look into replacing/rebuilding?
Also, know any good gs carb rebuild kits? I'll need the seals, and jets and whatnot.

Thanks.

P.S. The screws on my exhaust pipes and seized, and I kind of stripped one:mad: How should I go about freeing them without causing any damage?

Quote from: spaceboy on October 05, 2009, 05:14:13 PM
Thanks for the reply.

Which vacuum lines should I be checking and do you have a link to float adjustment? Should I just take the carbs out, so that I can check all the screws?

There is only one vacuum line:  It goes from the petcock to the left carb.  There are other places for vacuum leaks to occur, such as the top caps or the rubber boots between the carbs and head.  Float adjustment is covered in the service manual and the Wiki (http://wiki.gstwins.com/index.php?n=Maintenance.FloatHeight).  But I adjust mine with the carbs mounted.  I check float height first (http://www.bbburma.net/FloatHeight.htm), then remove the bowls.  Pull the float assembly out and adjust the tang as needed.

So I finally had to chance to check my float height. Turns out its very low on both carbs. Zing.
I tried to get the tank off, but two of the hoses coming from it are completely stuck. I tried working them off but to no avail.

Any suggestions?
I was thinking maybe to just make a slit and slide them off, and replace the lines. One coming from the main, the other from the middle. Would this be my best option?


Also, I want to rebuild my carbs over the winter. Any recommended kits with all the seals and a set of jets?
While I'm at it, I'll need a bunch of other seals as well. Is there a central site that I could visit that stocks these?

Thanks.

Try sticking a screwdriver blade between the top edge of the fuel line and the fuel tank.  You will try to push the lines off of the tubes, not pull.  But if they are original '94 fuel lines, you may want to replace them anyway.

Recommended carb rebuild parts come from the buddha.  Other parts you can get at bikebandit.com or ronayers.com

Good idea, I'll just replace the fuel lines.

Bikebandit seems to have almost everything, and I'll be sure to PM buddha for carb parts.

Thanks a bunch.