Okay, I looked everywhere before making this post, and, alas-- I found nothing.

In December the bike was running well until I left town. I came back to find it had fallen on its left side. I righted the bike but had to leave town before I could winterize it. Three weeks ago I tried to start it for the first time since i've been back at home. It turned over, but wouldn't catch so here's what I did:

Disassembled carburetors, petcock (under both the tank & the one with 'pri', 'on', & 'reserve'), cleaned & replaced fuel & vaccuum lines. I also replaced the breather box & very-dirty air filter with the K & N lunchbox, changed the oil (which smelled strongly of gas), and cleaned carbon off of the plugs. The battery's electrolyte levels were still tip-top.

Following these steps bike turns over, catches & runs-- that is, for 10 seconds, then dies, not to start & catch again for an hour or so. I even tried to get a running start & kick it into 2nd at 10 mph, but nothing works. Any ideas? Thanks in advance,

Brand new member,

Jonathan

Starter turning over?

Choke?

Did you let it prime first and use the choke?  And this may be dumb but did you clean out the tank?  If it was sitting for that long with gas in it there could be gunk that clogged up your newly cleaned carbs.

You mentioned that you replaced the stock air filter and box with a K&N lunchbox. Did you rejet appropriately? Otherwise you would be running very lean, which may contribute to the trouble you're having.

Well, go with the system you touched last. I'd check your carbs again to make sure everything is assembled correctly. In fact, the first and easiest test I'd do is to check the float heights. This will not only eliminate the float heights as a possible source of your problem, it will verify that there is gas in the carbs. Also, check your spark to make sure that is still good and make sure your battery is well charged and that the charging system is doing the right thing.

First of all, thank you very kindly for the help.

The starter does turn over, & the bike runs only if I have it choked (& it runs for about 10 seconds), which I believe I have properly adjusted on the carburetor. Note: I did drain & clean the gas tank. My next step-- after fred's post-- will be to check my float heights. I've never done that, but I'm sure there's a link around here somewhere. . .

I am definitely getting a spark on my left side. Funny story, though: I live near a rough neighborhood in Illinois. When I removed my right plug & turned the bike over to check for a spark, there was a sound like a gunshot out of the cylinder. A guy walking by in my street hit the ground like he was in the rice paddies of Viet Nam. . . ;P I'm a little nervous to see again if that plug is sparking. Is there another test for this?

How long do I let the bike prime before using the choke?

I have my jets ordered, but haven't done so, yet (All of this is first-time for me, in case you haven't noticed). Would the bike really not run because of that?

Jonathan

Here's a link to the float height check.
http://gstwin.com/float_height_check.htm

Since putting on the Lunchbox your air/fuel would be too lean with stock jetting.  Try putting the choke on and putting a rag on top of the air filter to richen things up a bit.  See what happens.

"How long do I let the bike prime before using the choke?"
Prime just bypasses the vacuum diaphram in the petcock and allows fuel to flow regardless of vacuum.  You can use the choke and prime at same time.

Here's the jets I ordered for my lunchbox breather:

N100.604 Mikuni 140 Main jet; M28/1001, 40.0 Pilot jet

However, the pilot jet I ordered isn't what the gs500 wiki site suggested-- they suggested N151.067 (40). Both are the same size, right (40)? Does it matter that this is 'M28/1001'? Is this a different manufacturer/size? Do I need to send it back? Like I said, I'm new at a lot of this. . .

Jonathan 

This is precisely why I sell jets.
You have lunch box, and lemme guess you're running stock pipe ?
Anyway tell me your filter+pipe setup, and the year as well, and I'll tell you what to run.
Heck this is also why I do carbs for people, so we aren't cluttered with a million posts of why the bike isn't running.
Anyway, post up and I'll tell you what to get.
Cool.
Buddha.

The Buddha--

Yep, the bike's a 2000 with stock pipe, lunchbox breather, & I have stock jets in it. I followed the chart on Wiki gs500 & ordered 140 mikunis & 40s (though not the number  N10x.xxx whatever they suggested) to replace the old pilots.

I've looked at numerous ways of rejetting so far (including my manual) & don't understand exactly what it means by leave jets two or three "turns out". ??

Just a note, though-- I got the breather for $20 from a buddy, so I thought "What the hell? I'll free up some space under my tank!"

Thanks,

Jonathan