I have a 1992 with 1992 wiring, a 1998 engine, and 2008 carburetors. Yes, Frankenstein's GS.

Now my problem is the motorcycle can rev beautifully in neutral, has a great idle of around 1400-1500, will redline at WOT, and will decelerate a bit slow probably due to my throttle cable routing.

But my biggest issue, is pop it in 1st (or 2nd), and after a brief hiccup, it'll idle around 1400 and start acting up when I give it throttle. Just coughing nasty blegh. The video really explains it.



Also, with acceleration comes smoke. I can't tell if it's blue-ish white or just plain white, but it's not dark. Also in the video.

HELP??

I don't think throttle cable routing will cause the revs to fall slowly.  Either the routing will cause the throttle not to close fully (result in high idle), will snag when you turn the bars and cause the throttle to open or slack to gain in the control, or it won't be an issue at all.
If the throttle cable is to blame at all, it would also feel "sticky" when you twist it.

I think you've got a vacuum leak.


Speculating out loud on the whole chugging in gear thing.  Multi-plate wet clutches can be sticky.  Even with a clutch fully disengaged, they can offer resistance to the engine.  Heck, my Buell "jumps" under me when I cold start in gear with the clutch fully in, but once it warms up the clutch is sufficiently loose and this doesn't happen anymore.

When you're in neutral the whole clutch basket spins freely.  When you toe down into first, essentially the transmission "picks up" half of the clutch plates and the mass of the motorcycle holds them in place while the other half still spin with the engine.  The oil sticking up these plates and the friction caused by their proximity causes a natural resistance.
If we're assuming we have a bad vacuum leak causing the engine to be lean, it'll be low on power.  Throw in a sticky clutch and it might just be enough resistance to bog it.

When you knock it into gear and have the clutch pulled in, do you see the rear wheel wanting to rotate?

To clarify, I don't think this is the cause of the issue. It may just be a contributor to the symptom you see.



White smoke usually means moisture.  If it had recently rained you could be blowing out any water accumulated in the exhaust.  If it doesn't go away, you're sucking in moisture from somewhere.
Water in gas is a good place to start.  It'll cause a mess of running problems.  If not then it could point to a vacuum leak.  Especially if you're in an area with high humidity.
Blue colored smoke would indicate burning oil.
Black smoke is a rich mixture.

I agree with watcher about the vacuum leak. The smoke in the video is burning oil. That's rings.

I think your revving issue is electrical but my first thought was clutch drag. However, I think this much drag would cause the bike to lurch. So I still would start with electrical checking. Clutch switch, neutral switch, side stand switch and relay, etc. Even that double diode between the neutral switch and side stand switch bears checking.

Quote from: mr72 on October 17, 2016, 08:36:09 PM
The smoke in the video is burning oil. That's rings.

It doesn't look blueish to me.  Then again I'm watching on a smart phone so maybe I'm not seeing it too well.
Unfortunately there's no easy way to inspect the rings.

Quote from: Watcher on October 17, 2016, 09:50:14 PM
It doesn't look blueish to me.  Then again I'm watching on a smart phone so maybe I'm not seeing it too well.
Unfortunately there's no easy way to inspect the rings.

Right. Once you are inspecting the rings, it only makes sense to replace them. And do the head. And you are buying a gasket set. That's a top end rebuild. I know because my bike is in the shop right now getting it done.

But hey, it's way easier to check and do this on a GS500 than on a car! In fact, if it wasn't already at the shop when we discovered this was the problem, I would have done the top-end job myself. It's not that hard.

Anyway, there's no source of water in an air cooled engine. So that smoke has to be oil, it's bluish enough. If it's real cold you might get condensation in the air that causes "white" smoke when the engine is cold, but the amount of actual H2O you could get into a motorcycle in the crevices and airbox and droplets in the intake etc. would burn off in like 5 seconds. You're not going to repeatedly rev it for minutes at a time like diagnosing a problem and have it still burning water. It'd never start if there was that much static water in the fuel/air system. On a water-cooled engine you can get white smoke with a blown head gasket or cracked head because as it runs it is constantly replenishing water directly into the cylinders, but on an air-cooled bike you'd have to have water sitting and enough to last more than a few seconds would be too much.

IMHO, of course. I'm no expert. But I know oil burning past rings, very well, and I know water burning from blown head gaskets and cracked heads. That is oil smoke.

The thing is, if you have that much oil smoke you have to consider rings, which means you might consider compression, and then it's a complicated range of diagnoses until you repair the compression and rings.

But I still think this specific problem, not revving when not in neutral, is electrical. There are a few safety switches and a relay in there that and/or their way to supplying power and ground to the coils and igniter and if one is bad or the igniter ground path is bad then it could cause this condition.

Quote from: mr72 on October 18, 2016, 06:01:37 AM

Quote from: Watcher on October 17, 2016, 09:50:14 PM
It doesn't look blueish to me.  Then again I'm watching on a smart phone so maybe I'm not seeing it too well.
Unfortunately there's no easy way to inspect the rings.

Right. Once you are inspecting the rings, it only makes sense to replace them. And do the head. And you are buying a gasket set. That's a top end rebuild. I know because my bike is in the shop right now getting it done.

But hey, it's way easier to check and do this on a GS500 than on a car! In fact, if it wasn't already at the shop when we discovered this was the problem, I would have done the top-end job myself. It's not that hard.

Anyway, there's no source of water in an air cooled engine. So that smoke has to be oil, it's bluish enough. If it's real cold you might get condensation in the air that causes "white" smoke when the engine is cold, but the amount of actual H2O you could get into a motorcycle in the crevices and airbox and droplets in the intake etc. would burn off in like 5 seconds. You're not going to repeatedly rev it for minutes at a time like diagnosing a problem and have it still burning water. It'd never start if there was that much static water in the fuel/air system. On a water-cooled engine you can get white smoke with a blown head gasket or cracked head because as it runs it is constantly replenishing water directly into the cylinders, but on an air-cooled bike you'd have to have water sitting and enough to last more than a few seconds would be too much.

IMHO, of course. I'm no expert. But I know oil burning past rings, very well, and I know water burning from blown head gaskets and cracked heads. That is oil smoke.

The thing is, if you have that much oil smoke you have to consider rings, which means you might consider compression, and then it's a complicated range of diagnoses until you repair the compression and rings.

But I still think this specific problem, not revving when not in neutral, is electrical. There are a few safety switches and a relay in there that and/or their way to supplying power and ground to the coils and igniter and if one is bad or the igniter ground path is bad then it could cause this condition.

I'm inclined to agree with you regarding the smoke. If it were condensation in the headers/muffler, it would evaporate rather quickly. My bike shoots white smoke for like 30 seconds when i start it on cool, humid mornings. But, to constantly spit light smoke, i think that's probably burning oil.

However, I think Watcher's answer regarding the revs makes sense to me. Vacuum leak seems more likely to me than an electrical reason for the engine to rev differently depending on gears. If it were an electrical issue, I would think it would still rev badly in neutral.

Of course, the vacuum leak is probably less of a concern than the whole "probably needs a top-end rebuild" thing lol.

Quote from: qcbaker on October 18, 2016, 06:17:21 AM
However, I think Watcher's answer regarding the revs makes sense to me. Vacuum leak seems more likely

I think the vacuum leak is in response to the hanging idle while revving down when in neutral, not the explanation for why it won't rev when not in neutral.

Quote
to me than an electrical reason for the engine to rev differently depending on gears. If it were an electrical issue, I would think it would still rev badly in neutral.

On the contrary, due to electrical logic on ground and power to the ignition module, switching from neutral will change the electrical circuit such that it could starve the coils or igniter for current, while in neutral the neutral switch provides a parallel ground path and may allow it to run correctly.

The difference in running as far as I can tell from the video (in the other thread?) is switching out of neutral. Has nothing to do with drag or gears or trying to run the bike on the road. It's on the side stand, it runs fine (but with oil smoke and hanging idle...) revs up and down when in neutral, then switching into gear immediately the revs drop like it is running only on one cylinder and then it refuses to rev at all off idle. That's classic no-spark on one cylinder TO ME. And the neutral switch offers the explanation for why it works ok in neutral, but it's not that it's a BAD neutral switch, it's that the neutral switch works around whatever is wrong with it, making it run ok in neutral and not ok any other time.

You can chase the wiring diagram and see what part of the circuit could be affected by the neutral switch being on to target the issues, or just chase wires and test components.

Quote
Of course, the vacuum leak is probably less of a concern than the whole "probably needs a top-end rebuild" thing lol.

Haha. But the bike should run somewhat even with worn rings, but fixing any vacuum leaks can make it run as well as it can. And vacuum leak is a user-serviceable thing far more than rings.

Quote from: mr72 on October 18, 2016, 07:05:45 AM
On the contrary, due to electrical logic on ground and power to the ignition module, switching from neutral will change the electrical circuit such that it could starve the coils or igniter for current, while in neutral the neutral switch provides a parallel ground path and may allow it to run correctly.

The difference in running as far as I can tell from the video (in the other thread?) is switching out of neutral. Has nothing to do with drag or gears or trying to run the bike on the road. It's on the side stand, it runs fine (but with oil smoke and hanging idle...) revs up and down when in neutral, then switching into gear immediately the revs drop like it is running only on one cylinder and then it refuses to rev at all off idle. That's classic no-spark on one cylinder TO ME. And the neutral switch offers the explanation for why it works ok in neutral, but it's not that it's a BAD neutral switch, it's that the neutral switch works around whatever is wrong with it, making it run ok in neutral and not ok any other time.

You can chase the wiring diagram and see what part of the circuit could be affected by the neutral switch being on to target the issues, or just chase wires and test components.

I guess that makes sense. It's probably a combination of things causing all the issues.

I guess that makes sense.