Got it started again! Needs tuning...

[scroggins5000]

I just bought a '92 GS500E from a friend to resurrect for fun that I got real cheap. It's super dirty, and needs some work. The carbs and starter have been rebuilt. I slapped those on first, put some gas in the tank and tried to fire it up to see if it would catch. No luck.

I got new NGK sparkplugs, but the old champions didn't look that bad. I took the carbs back off, and went through them to make sure the jets were clean and they were. Put everything back together still wouldn't start. Spark was good, compression was there, so I start checking fuel lines. They were clean.  

I spray a shot of carb cleaner in the intakes, and it fires right up and dies. So I know it has to be fuel somehow. I empty the tank and find the culprit. I had looked in the tank, but didn't see it. There was some water in the bottom that had accumulated there from sitting outside for a couple months... I dry out the tank, the carbs, and put new gas in. Still not firing, and I try the carb cleaner again. It fires right up and stays running (no choke, I need to replace the cable, it rusted through in a spot). I let the engine get warm, set the idle screw to about 1200-1300RPM. I kill the engine, and wait a few minutes to try a restart. It fires right back up, no choke. Sounds great.  

The next day I try to start it and it won't fire (with choke on or off). Any suggestions on where to go from here???

FYI: It has K&N filter and Vance & Hines exhaust. I'm not sure if the jets are stock or not.

[bombjack]

If your choke is out of order like you said, it's not easy to start a GS on a cold day.
The first time you got it started you used carb cleaner to get it running.
You can manually choke it by putting a piece of cloth in the airfilter.

Good luck!

[scroggins5000]

I tied the clutch handle in so I could start it one handed. I used my other hand to push in the choke on the carbs and it still wouldn't start. Also, the temperature here lately has been in the high 80's. Technically a cold start none the less, but not bad.

[RichDesmond]

When you cleaned the carbs did you drill out the covers on the fuel screws and pull them out and clean them and the idle circuits?? If you didn't that's likely the cause.

[scroggins5000]

When you cleaned the carbs did you drill out the covers on the fuel screws and pull them out and clean them and the idle circuits?? If you didn't that's likely the cause.

I'll look into that. Once you drill out the covers on the fuel screws, do you need to replace them or will they be fine without the covers?

[OilSooner]

fine without covers.  once its out, you wont be able to get them back in, and they are not needed anyway.

EDIT:  when you take them out, count how many turns they are in first.  You must put them in the exact same way, unless you know how to turn them in and out to change your mixture.

[scroggins5000]

fine without covers.  once its out, you wont be able to get them back in, and they are not needed anyway.

EDIT:  when you take them out, count how many turns they are in first.  You must put them in the exact same way, unless you know how to turn them in and out to change your mixture.

How many turns should they be in if they were still stock. Thinking back at when I first looked at it, I believe the covers have already removed. When I check them again I want to make sure they were put back properly.

What's the best way to clean out the idle circuit?

[RichDesmond]

When you cleaned the carbs did you drill out the covers on the fuel screws and pull them out and clean them and the idle circuits?? If you didn't that's likely the cause.

I'll look into that. Once you drill out the covers on the fuel screws, do you need to replace them or will they be fine without the covers?

Fine without. Those plugs are EPA-mandated to keep you from futzing with the jetting. Since you haven't cleaned them yet I'd bet that's the problem. Just be careful when you take the screws out, there will be a spring, an o-ring and a tiny washer in there too. Don't lose anything, and get them back in the right order.
Blast a bunch of carb cleaner through the hole you took the screw out of, and then blow it out with compressed air.

[RichDesmond]

This is an excellent thread from the SV board on carbs and carb cleaning.

http://forum.svrider.com/showthread.php?t=85580

The SV carbs are slightly different from the ones on the GS, but they are similar enough that most of it applies.

[scroggins5000]

When you cleaned the carbs did you drill out the covers on the fuel screws and pull them out and clean them and the idle circuits?? If you didn't that's likely the cause.

I'll look into that. Once you drill out the covers on the fuel screws, do you need to replace them or will they be fine without the covers?

Fine without. Those plugs are EPA-mandated to keep you from futzing with the jetting. Since you haven't cleaned them yet I'd bet that's the problem. Just be careful when you take the screws out, there will be a spring, an o-ring and a tiny washer in there too. Don't lose anything, and get them back in the right order.
Blast a bunch of carb cleaner through the hole you took the screw out of, and then blow it out with compressed air.

Cool. I actually remember that the plugs are already off. I will go through these tonight, and see if it helps.

[scroggins5000]

This is an excellent thread from the SV board on carbs and carb cleaning.

http://forum.svrider.com/showthread.php?t=85580

The SV carbs are slightly different from the ones on the GS, but they are similar enough that most of it applies.

Thanks for the link. Here is another one I just found that has a lot of good info about breaking down and cleaning a set of Mikuni BST36SS on the GSX that is extremely similar to the BST33SS on the GS500E. I thought I should share.

http://www.gixxer.com/forums/showthread.php?t=159718

[scroggins5000]

I also found this link regarding a simple how to on re-jetting. At the end it has instructions on how to correctly set the pilot air screws.

http://www.angelfire.com/mt2/mikesgs500/rejetting/

Lots of helpful pictures too!

[scroggins5000]

More questions... I'm assuming the jets in the carbs might still be stock, but I'm not sure. How can I check this? According to what I've read at the below link I would need #150 mains, because it has V&H exhaust and the K&N filter that's on it.

http://www.angelfire.com/mt2/mikesgs500/rejetting/Rejetting_Matrix.html

[pandymai]

the jets are stamped with numbers. once you pull them out you should be able to see them. mains have it stamped on the head, the pilots should have it right under the threading

[Syzygy]

Hmm...

My GS has been giving me great joy but at times will be loath to start.  I never did pop out the idle jets when I cleaned the carbs after sitting with gas for four years... perhaps this is my issue as well. The only problems I have with the bike are unpredictable idling (sometimes 1500, sometimes lower... sometimes changes if I lean the bike over at a stop!)

I have been meaning to look at my choke configuration and if I'm going that far, maybe drilling out the idle jet covers and giving them a good once over is the way to go!

Peace,
Syzygy

[scroggins5000]

I took the carbs off, and checked them thoroughly. Sprayed carb cleaner through every opening, and no clogs whatsoever. Everything is really clean.

I found a small o-ring missing in the top portion of one of the carbs (#26). It has been discontinued, so I think I'm going to try my luck matching it at the hardware store. Anybody have an extra lying around??

The washers on the needles are set at the 2nd notch from the top. The diaphragms emulsion tubes look really good.

I tightened down the pilot screws before removing them to see how far they were backed out. They were set at about 5 turns out! I know every bike will be different, but that seems too much. I took them out, and there were no washers (#21) in between the springs and the o-ring (#20). Also, one of the o-rings had a chunk missing from it. I ordered new o-rings and washers for both sets. The idle circuits were clean. All jets were clean.

When I put them back together, I will start at 2 turns out and work from there. I have not checked the float height yet, but I will adjust that as well.

[Homer]

Sounds like somebody was trying to fix the same problem, and lost the o-ring in the process.

Did the 5 turn thing, myself, once.  Counted 1/2 turns, instead of complete rotations.  I wanted 2.5 turns out, which is perfect for mine. 

I'd like to know the sizing of those little boogers too! 
Need to replace both #57s, 17, 45, and especially 29.  29 is an important one. 

[utgunslinger13]

When I replaced the O-Rings, I took the carbs into one of the big box autoparts store (can't remember which, it was in Phoenix) and they had this huge box with multiple sizes of O-Rings.  We just randomly grabbed sizes till we found ones that matched.  Hell, after about 3 minutes we had them all replaced and he wouldn't even charge me!

[scroggins5000]

Ok, so the other day I got all my o-rings and washers in. I slapped the carbs back together. Set the idle screws at 2 full turns out to start. After I replaced my choke cable I put the carbs on the bike, and tried to get it started. choke all the way on, and it fired up almost immediately. RPM's only went up to around 2-3k. After letting it warm up for a while and slowly backing off the choke, if I tried to take it off completely, it would just die. All the mean while it has a kind of stutter every so often. I guess it's too lean.
Today, I adjusted the idle screws to 2.5 turns out, and started it again with the choke on. It revved up higher this time, but after warming up it still had to rely on the choke or it would die. It is still is running rough too, and stutters every once in a while. I guess still too lean? I eased on the throttle slightly to see what would happen and it revs up fast and has a delay before the RPMs go back down...?
How many full turns out is normal, 3? If I end up going past that to make it idle at the right RPM's, would installing bigger main jets help? I think the number on mine are 134's (Don't forget I have a Vance&Hines + K&N). Also, what would cause the stuttering of the engine?

[007brendan]

Did you ever find out what size jets your carbs have?  It should be printed pretty prominently on the top.  That sounds like the most likely culprit for leanness.