So, I have posted a lot on here since the Fall, when I first acquired this 2000 GS500e.

It was sitting in a garage for 1 year+ before I bought it. Here's what I've done to revive it:

Oil change, sparks, new filter on factory airbox, new battery... all the basics.

Then I fixed the valve clearances. They were all at zero, now they're pretty close to spec (.01 high on the exhaust for instance). Once I did that it fired up, but ran rough.

I decided to rebuild the carburetor. Since it already had Vance and Hines full exhaust, I decided to also add a K&N Lunchbox. having taken the factory airbox in and out about a million times, the smaller size of the lunchbox in and of itself was a big attraction, but I thought since it had the full exhaust it might need an intake upgrade as well. Used the wiki to determine that 40 pilot and 150 main was probably about the best jet set up and rebuilt the carbs. The mixture screws are set to 3 turns out. The needle jet is clipped at 3rd position, with one nylon washer as well. The pilot jet is drilled style. (not the stock style)

Slapped the carbs on today, and it wouldn't start right away (it was 25F overnight here, but it's gotten really warm this afternoon). Gave it a shot of starter fluid and tried again. It lit up!

If I started it on wide open choke, I still have to give the throttle a few blips, but once over 4k RPM, it stays there for a second and then just slowly declines to stalling out. Knocks a little as it passes 2000 RPM.

If I start it with no choke, it has to be throttled to start, but will fall to a lowish idle (1100rpm) hang there for a few seconds and peter out to a stall as well.

Videos below

Here's what it sounds like on choke:

https://imgur.com/a/iE3wF5Y

Here's me starting with no choke:

https://imgur.com/a/iPjyqKQ

and here we are giving it a rev

https://imgur.com/a/MNuMZGw

it actually runs fairly smooth and sounds pretty decent at 4000-8000RPM.

BUT, if I hold the throttle open and steady at say 50%, it doesn't stay at 5000rpm indefinitely. It will drop or even die kinda suddenly. (that's what happened above when I held it at 5000 for a while, and it suddenly drops down to almost dying out)

Sounded like you were losing 1 cyl. And not keeping stead rpm for steady throttle could be running out of fuel likely pinched vent or bad petcock.
Cool.
Buddha.

Quote from: The Buddha on February 17, 2021, 10:05:18 AM
Sounded like you were losing 1 cyl. And not keeping stead rpm for steady throttle could be running out of fuel likely pinched vent or bad petcock.
Cool.
Buddha.

Frame petcock is leaking, which is new. Do you rebuild, or replace?

if I am losing a cylinder, what's up with that?

Quote from: struckjm on February 17, 2021, 02:22:46 PM
if I am losing a cylinder, what's up with that?

Dont lose it, like take it and keep it ... dude its like this canadian chick who had a bunch of $$ bills (not real $$, the fake plastic crap from canadialand) and was yelling dont deflate it dont deflate it.
No idea why you losing a cyl, missing O ring, fuel flow, vacuum leak, plugged up crap, WFO something that's supposed to be plugged up ... It sounded like you drop a cyl, find if that is the case by checking exhaust for temp. That will tell you which one, then look at that carb and coils.
Cool.
Buddha.

Quote from: struckjm on February 17, 2021, 01:19:46 PM

Frame petcock is leaking, which is new. Do you rebuild, or replace?

When I had a problem in the past, I just replaced... it has been working well for about 8 years now.

I've read about rebuild kits working well... but I don't have any personal experience with them.

Found a K&L replacement for the petcock on eBay pretty quickly. I think that's exactly how I got the tank petcock. The tank was stored dry and I think the gaskets dried out.
Since the frame petcock was disconnected for months, maybe that happened there too.

I have encountered now 3 GS:s which had leaking membrane in the frame petcock and that results the left cylinder to shut off due to direct gas leak into it via vaccuum hose. Get rid of that old petcock!    There is some fans of the original petcock but the structure of it is horrible and it does not provide enough fuel eventually, I hate it.

And all of these GS are ind Finland which is relatively cold place so I suppose the cold conditions results the rubber membrane in petcock to go bad.

Quote from: nurms on February 21, 2021, 08:14:14 AM
And all of these GS are ind Finland which is relatively cold place so I suppose the cold conditions results the rubber membrane in petcock to go bad.

That's a possible explanation. The bike is stored in a shed, and the weather has been very cold for our climate. Overnights being 20-25F.

Update: I re-examined my whole carb setup and I discovered a problem.

I had hooked up the vacuum tube from the farm petcock to the RIGHT Carb. So I reattached it to the left carb instead.

Here's a video of that. Sorry for the camera work, I had to place my iPhone in my breast pocket and try to aim my chest in the direction we're looking.

https://imgur.com/gallery/m6StUYW

So, I started the bike on prime and choke and it rips up to 7-8k rpm. I can lower the choke to just about anything except totally closed and keep it running at a corresponding rpm. Ie 50% choke open it stays at 4000rpm. Turn the choke off and it struggles. Doesn't die. I turned the idle mixture screw in about 2 turns and it idles at 1500rpm, but...
it seems to skip some fires, there's some slapping sounds. There's some smoke. Oi vey.

So, I have size 40 solid (not bleed) pilot jets in the mail, as well as a new petcock. But I think my petcock symptoms were caused by vacuum tube going to wrong place.

What are y'all's thoughts? What do I try next?

Both exhaust pipes are HOT

Damn I wonder where you have attached the vacuum hose because it does not attach to the right carb in any way I think? I suppose it is still in wrong place I will find you picture from the exploded view. Feel free to play with the idle screw GS does not run without chocke until quite a few minutes.

I'm fairly sure the vacuum tube is now attached to the correct location on the left carb as described in my Clymer, but could be wrong.

Side note, but big deal to me:
Left cylinder has 147PSI and right cylinder has 152PSI. I originally had no compression before readjusting valve clearances. The. A bad gauge made me think it only had 90PSI.

And here's what the plugs look like after running for five minutes at 4-8000rpm.

https://imgur.com/gallery/HmDzh2C

The bike from me which had vacuum leak from the vacuum line to the left cylinder had similar plug as you have on the left!

I have issues with attaching pictures but if you have a manual you certainly got it right already!

I think you should bring valves within spec it is actually very important! Also your carbs will nees sync after major valve adjustment.

I watched the video and the cylinder having black plug definitely skips flame once in a while. That cylinder quite certainly has a vacuum leak from intake boot or somewhere else eg. the vacuum hose which we have discussed.