GS500 not firing - help with diagnoses/potential ailments

[restless]

My gs500 is just turning over and the cylinders are not firing. It was running a few months ago but then I left for three months due to a work opportunity with the hope my dad would use it and it just sat. Here's what I've done:

1. Cleaned Carbs and Jets thoroughly (with exception of emulsion tubes), New orings for the pilot screw, float needle seat, engine intakes.
2. New spark plugs
3. Clean gas tank and in-line fuel filters
4. Battery is at a full charge according to my tender

Here the problems I know need to fix but it's hard to believe this would cause the bike to not fire:
1. There's a small rip on the pilot needle o-ring
2. missing the tiny o-ring on one of the vacumm port caps
3. I did not change the float needle seat as suggested by some members at the forumf
4.  the pilot screw was turned ~5 turns out - which makes me wonder if the person rejetted - the exhaust is clip on and not stock. I reset the pilot screw to 2.5 turns out. There's no tach when I got the bike so no way to know what the idle was/is

Could any of these problems cause the bike to just turn over but not fire?


Thanks for any help. I'm really stumped and if it's electrical - I'm not sure if I'm capable of fixing it myself (regardless of how stubborn I am).

Thanks all!

[Kilted1]

The fastest way to diagnose whether your issue is with the carbs or not is with a shot of starting fluid.  If it fires up, it's carbs.   If not then it's either electrical (ignition system) or mechanical (valves, timing, etc).

Sounds like your carbs were pretty out of whack to start with and you've now made blind adjustments and altered things without fixing everything you know needs fixing.  Are you really that surprised it doesn't run?  Order the kit, replace ALL the O-rings, you'll be back on the road in no time.

[J_Walker]

First of all, your carbs are all kinds of wonky, you and I both know this as you went on much detail on what you knew was not correct on them.

Fuel
Air
Compression
Spark

You just need these four basic things.

[restless]

The fastest way to diagnose whether your issue is with the carbs or not is with a shot of starting fluid.  If it fires up, it's carbs.   If not then it's either electrical (ignition system) or mechanical (valves, timing, etc).

Sounds like your carbs were pretty out of whack to start with and you've now made blind adjustments and altered things without fixing everything you know needs fixing.  Are you really that surprised it doesn't run?  Order the kit, replace ALL the O-rings, you'll be back on the road in no time.

You make a good point and I shouldn't have been surprised - I think I was being naive in thinking all of those minor issues should not have prevented the bike from at least firing. I'll order the kit and may return to this thread if/when I get stuck. Have you ordered a kit off Ebay/Bikebandit? I've seen some recommended kits but they're mostly for earlier gen GS's.

Thanks and apologies for obvious naivety.

[Kilted1]

I've ordered piles of kits from ebay and Amazon.  Some are great, some are fine aside from maybe missing a washer or e-clip or something.  One time I got two different kits, at least one of them was the right one.  Last I looked, the GS500 kit was $30 or $40 on ebay, but the DR350 kit (which is a single carb of the same model) was only $10 or $12.  The dealer or pro shops want several times that for the same bag of parts and still have to order it in.  From ebay as far as I know.

Read mr72's blog regarding carbs.  Get the O-ring kit he mentions in there, actually get two of them.  There's O-rings in there that aren't usually included in most rebuild kits.  https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html?view=flipcard

[restless]

I've ordered piles of kits from ebay and Amazon.  Some are great, some are fine aside from maybe missing a washer or e-clip or something.  One time I got two different kits, at least one of them was the right one.  Last I looked, the GS500 kit was $30 or $40 on ebay, but the DR350 kit (which is a single carb of the same model) was only $10 or $12.  The dealer or pro shops want several times that for the same bag of parts and still have to order it in.  From ebay as far as I know.

Read mr72's blog regarding carbs.  Get the O-ring kit he mentions in there, actually get two of them.  There's O-rings in there that aren't usually included in most rebuild kits.  https://joshkarnes.blogspot.com/2017/09/fixing-common-gs500-carburetor-issues.html?view=flipcard

The Dr350 idea is a great one - I already replaced the o-rings that I mr. 72 suggests - I didn't replace pilot jet and needle seat but will knock out those two. The trickier one is finding the oring that goes on the diaphragm needle give there's a small piece missing.  That's what causes me to think I should just order a kit off of ebay or amazon but having trouble figuring out which is a good quality aftermarket kit

[sledge]

https://litetek.co/Carb_Kit_Suzuki_GS500_89-96.html

Best quality kits I have ever used. Don't bother with those crap low quality incomplete eBay kits, unless of course you want to compromise and take a chance 

And if you are going to do a carb rebuild do it properly and don't, like most people do, forget the slide housing orings and the choke plunger seals.

[restless]

https://litetek.co/Carb_Kit_Suzuki_GS500_89-96.html

Best quality kits I have ever used. Don't bother with those crap low quality incomplete eBay kits, unless of course you want to compromise and take a chance 

And if you are going to do a carb rebuild do it properly and don't, like most people do, forget the slide housing orings and the choke plunger seals.

These look great - unfortunately it doesn't look like they include the o-rings that go right above the diaphragm needle. But regardless it looks like they have pretty much everything else required. Thanks for the tip!

[The Buddha]

https://litetek.co/Carb_Kit_Suzuki_GS500_89-96.html

Best quality kits I have ever used. Don't bother with those crap low quality incomplete eBay kits, unless of course you want to compromise and take a chance 

And if you are going to do a carb rebuild do it properly and don't, like most people do, forget the slide housing orings and the choke plunger seals.

These look great - unfortunately it doesn't look like they include the o-rings that go right above the diaphragm needle. But regardless it looks like they have pretty much everything else required. Thanks for the tip!

O rings above the diaphragm needle ?
Sorry no such thing, on the 01+ when you buy a kit from me I include O rings if you need spacers in addition to the one that sits on top of the e clip ...
Cool.
Buddha.

[restless]

https://litetek.co/Carb_Kit_Suzuki_GS500_89-96.html

Best quality kits I have ever used. Don't bother with those crap low quality incomplete eBay kits, unless of course you want to compromise and take a chance 

And if you are going to do a carb rebuild do it properly and don't, like most people do, forget the slide housing orings and the choke plunger seals.

These look great - unfortunately it doesn't look like they include the o-rings that go right above the diaphragm needle. But regardless it looks like they have pretty much everything else required. Thanks for the tip!

O rings above the diaphragm needle ?
Sorry no such thing, on the 01+ when you buy a kit from me I include O rings if you need spacers in addition to the one that sits on top of the e clip ...
Cool.
Buddha.

I'm probably not describing this correctly but the plastic clip that holds the spring that sits on top of the needle washers has an o-ring with a slight tear. Buddha do you mind pm'ing me the cost of your kit?! Best