20002 GS500 idle problems

[straxcla]

Ok so I picked up a 2002 GS500 about two years ago, it was running great until a couple of months ago. It started getting really hard to start, first I thought this was an issue with the cold, but it got worse and now it takes a good 5-10min of cranking, choking, coughing, stalling and revving to get the thing running. Strangely enough as soon as it's ridden for maybe 5min it will stall if let down to idle, but start right back up again no problem. Once the bike is properly warmed up it will still stall occasionally, for example when I pull the clutch in and coast into a parking spot etc. Also (once warmed up and idling) it has this strange sort of throttle delay when revving in neutral that I never remember having before. A quick snap of the throttle leads to a delayed rev up, and a slow decent back down to idle. None of these problems seem to affect the bike while I'm in motion and riding. In attempt to fix I replaced spark plugs, battery, and did a quick cleaning of the carb, even though it didn't appear to be dirty at all.  Any ideas on how to at least fix the starting issue?

Thanks

[cyamaura]

How old is the gas?

[adidasguy]

We had problems like that with one bike here in West Seattle.
Buddha was correct that clogged pilot jets cause that.
Cleaned carbs then all was OK.

[cyamaura]

I had same problem caused by bad gas cleaned the jets drained the gas problem solved

[BockinBboy]

Hmmm.... leaning toward tight exhaust valves here...

- Bboy

[straxcla]

Like I said I did clean the carbs, took out the jets and soaked them in a little carb cleaner. Plus I've never run anything but Premium gas in the bike, when I'm only buying 4 gallons at a time I figured why not. Bboy, can this issue be fixed with a valve cleaning and adjustment?

[radodrill]

The valves do tighten up over time; when they get too tight, this restricts air from entering or leaving the engine (based on which valves are too tight).

[cyamaura]

If the gas is bad cleaning the carbs does nothing if you don't drain the gas. You might be having a different problem than mine but i had the same exact symptoms.in my case algae had actually grown in the gas clogging the jets. At about 3 months gas will deteriorate pretty noticeable.

[lucia_engel]

Try switching out premium with regular gas.

[cyamaura]

Lol why would you run regular if anything run ethanol free premium

[robfriedenberger]

Regular will run better in our motors due to low compression ratio, however premium usually is ethanol free thus eliminating carb issues. 

I always run premium because pulling carbs gets annoying after a few times.

[RossLH]

I've done plenty of travelling in the states, and I very rarely see pumps with ethanol-free premium. I fill my bike with 87oct every time, only ever had a problem when I cheaped out and went with an off-brand gas station. Ended up with a whole lot of water in the tank.

[Leadberry]

I've done plenty of travelling in the states, and I very rarely see pumps with ethanol-free premium. I fill my bike with 87oct every time, only ever had a problem when I cheaped out and went with an off-brand gas station. Ended up with a whole lot of water in the tank.

It's hard to find any ethanol-free gas here in NE Ohio.  I drove through Iowa and Nebraska not too long ago and it seemed pretty prevalent out that way.

[chsonnu]

Straxla, did you figure this out?  I suspect that it is also the valves because I have a similar issue and my carbs are pristine.

[straxcla]

STILL haven't figured this out, or checked the vales yet. But since its warm out I've been riding a lot and have noticed some more symptoms. When warmed up and upon restarting after one (of many, and way to frequent stall-outs) the bike likes to rev up and idle at about 4k rpm for a minute or two, without having the choke on, this happens randomly. Gas millage has also dropped, which may be due to the fact that I can rarely let it fall below 2k rpm or it stalls. Today I tested my top speed on flat ground, had the throttle pinned in 6th gear, probably for about a mile, and it couldn't get over 80mph (I know it used to do about 115).  I need to figure this out before June, any more ideas? 

[straxcla]

Oh here's a video of me starting it in bout 50 degree weather. I did clean the carb jets and turn the mixture screw out 2.5 turns, but that didn't really seem to help anything

Battery is new along with the plugs

[Paulcet]

Almost sounded like it was running on one cylinder at 0:58. How do the plugs look?  And when were the valve clearances checked?

[AdamG14]

I had a very similar issue.  Had the carbs rebuilt and didn't fully solve it.  Ended up needing needles replaced and new float bowl gaskets.  Have you noticed any fuel around the bottom of the carbs?