Hesitation off the line

[Batan]

Seems like my GS500(a'94) has a hesitation problem off the line. Makes it a pain in the ass for my wife to ride, especially as it happens at right turns at the light or a stop sign. Well, it's a pain in the ass for me to but I ride the CB750 more then the GS.  I test rode it tonight and sure enough, it sometimes hesitates and feels gutless up until 4k, after that it's fine. It does not happen all the time but it does. It also stumbles at the first input of throttle before it picks up.
But, seems like if the idle is set lower, it seems to worsen the hesitation problem. If I set the idle higher, the sticky idle syndrome comes back.
I've had the bike since June and put just about 1k miles on it.
Last fall, the engine had been gone through by a shop, new seals and gaskets and such, new plugs blah blah. I have to take a look if there's been any carb work but they were most likely checked as the tank was lined as well.
Search on here reveals that I'm not the only one with the issue but the threads about them seem to end up more or less nowhere with no updates with what was wrong if fixed.

Ideas? Messing with the mixture?

Thanks.

[Batan]

I should add that I ran some Seafoam through the tank for good measure. But that did not really affect the bike.

[trumpetguy]

No idea if this is your problem or not, but about 8 months after I bought my bike with 11K miles on it, I adjusted the valves.  One exhaust valve was way out of spec.  Once the valves were correct, the low end performance got MUCH better.  Have you checked valves?

[Batan]

No idea if this is your problem or not, but about 8 months after I bought my bike with 11K miles on it, I adjusted the valves.  One exhaust valve was way out of spec.  Once the valves were correct, the low end performance got MUCH better.  Have you checked valves?

Haven't checked them but I need to find the bill for those repairs that were done on the bike for the PO, I think they probably adjusted the valves as well as the work came to cdn$1800!
That said, I think it's to intermittent to be a valve issue, I'm leaning towards fuel, or possibly spark but for some reason I think it's fuel related.

[theUBS]

Mine is similar.  On/off throttle produces a little hiccup.  Sometimes a stumble off the line.  Lower idle setting = more stumbling and even an occasional stall.  Higher idle setting = hanging idle.  Stay on the throttle and mine is fine though.  I'm leaning towards partially clogged pilot jets.   

[Batan]

Mine is similar.  On/off throttle produces a little hiccup.  Sometimes a stumble off the line.  Lower idle setting = more stumbling and even an occasional stall.  Higher idle setting = hanging idle.  Stay on the throttle and mine is fine though.  I'm leaning towards partially clogged pilot jets.   

Sounds EXACTLY the same. I dont really want to tear into the carbs if I don't have to or to discover it was not that.

[the mole]

Sounds like its running lean. Clean carbs, maybe washer on the needle+larger pilot jet. What say you Mr B?

[Villager]

If it only happens when you turn right then perhaps your throttle cable is either being trapped somewhere or is not properly connected? I've had that.

[ohgood]

Mine is similar.  On/off throttle produces a little hiccup.  Sometimes a stumble off the line.  Lower idle setting = more stumbling and even an occasional stall.  Higher idle setting = hanging idle.  Stay on the throttle and mine is fine though.  I'm leaning towards partially clogged pilot jets.   

hanging idle = lean condition (vacuum leak)

poor off idle performance = idler jet is partially clogged, poor jetting, etc

[Mdow]

check your jets i agree and also put a washer or two under the needles to help with the off the line start

[Juan1]

1.  Check the throttle cable.  Turn the bars all the way left and see if the problem persists.  The turn the bars all the way right and see if the problem persists.
2.  Check your mixture first.  Adjust the screws to 2.5 turns out, and go to 3 turns if the RPMs are slow to come down when you rev.
3.  WD 40 the vacuum lines one at a time while the bike is idling.  If the bike revs, you've got a leak.
4.  If you still have a problem at this point, then open into your carbs.

[Batan]

1.  Check the throttle cable.  Turn the bars all the way left and see if the problem persists.  The turn the bars all the way right and see if the problem persists.
2.  Check your mixture first.  Adjust the screws to 2.5 turns out, and go to 3 turns if the RPMs are slow to come down when you rev.
3.  WD 40 the vacuum lines one at a time while the bike is idling.  If the bike revs, you've got a leak.
4.  If you still have a problem at this point, then open into your carbs.

Thanks for the replies guys. It's not the cable as I checked it but will double check. I also checked for vacuum leaks and it did not appear to have any. However, I will check the mixture and try adjusting that, thanks for the info on that. Should I adjust the idle at 1200 before the mixture? Right not it's a bit lower then that, at about 1100rpm, I have to keep it low to keep it from hovering.

[moditup]

I had the same problem until yesterday!

From idle until 4000, it would bog down and creep up to 4000, once it hit 4000 it would take off like a banshee out of hell. I thought a rejet was in order and asked the shop to do it (I had the parts and it was time for a 4000 mile checkup anyway). The tech actually said rejetting wouldn't help, but he said he would adjust the valves and that would fix my problem.

Sure enough, throttle response down low is super smooth, from stop all way past 4000. It even sounds better. It feels like there is more power, but I think that's just because its smoother and doesn't bog.

[mach1]

if she is trying to launch below 5k than your going to have a hard time have her launch from 5k by releasing the clutch slowly and she will be fin ethe GS has no power what so ever under 5k unless you did some gearing work I have a 13t sprocket up front and still need to launch from 5k if I do sooner that its laggs but I can do it if need be.

[Batan]

if she is trying to launch below 5k than your going to have a hard time have her launch from 5k by releasing the clutch slowly and she will be fin ethe GS has no power what so ever under 5k unless you did some gearing work I have a 13t sprocket up front and still need to launch from 5k if I do sooner that its laggs but I can do it if need be.

No something is definitely wrong. It's laggy and it bogs down and it should not be. AFter all, it does not do it every time.

[theUBS]

if she is trying to launch below 5k than your going to have a hard time have her launch from 5k by releasing the clutch slowly and she will be fin ethe GS has no power what so ever under 5k unless you did some gearing work I have a 13t sprocket up front and still need to launch from 5k if I do sooner that its laggs but I can do it if need be.

  5k?  If you REALLY want to launch, I guess...  That just sounds quite a bit excessive to me. 

[mach1]

launch take off same shaZam! the GS has nothing to offer under 5k. at a redlight when I see the other side turn yellow I will blip the throttle and start off by the tim ethe clutch is 3/4 released Im at 5.5k then I dump it from their. before I rode it like it was a FI I4 power from idle to RL. nope the GS lags under load under 5k

[theUBS]

I know 5K isn't exactly peak power, but I can get the bike rolling with no problem with much less throttle--and I'm a pretty big guy.  I'm pretty sure you SHOULD be able to get the bike moving well enough somewhere between 2 and 2.5K without coughing or sputtering if carb issues are worked out.  For that matter, when I'm not running it hard, I SHIFT at less than 6K. 

[Batan]

I know 5K isn't exactly peak power, but I can get the bike rolling with no problem with much less throttle--and I'm a pretty big guy.  I'm pretty sure you SHOULD be able to get the bike moving well enough somewhere between 2 and 2.5K without coughing or sputtering if carb issues are worked out.  For that matter, when I'm not running it hard, I SHIFT at less than 6K. 

That's what I'm trying to say. I'm not asking for an advice how to launch it, I know that. But something IS wrong and I'm trying to look into solutions not patches.