breaking up when rpm levels off

[racejunky]

First off let me say hello to all. I only recently found this group and am very glad to be here,I think lol. If anyone has any info on why my '82 gs 1100 glz starts crapping out when the speed levels off I'd sure like to know how to correct it. This thing is scary fast as long as you're in the throttle and keeps getting up just as hard as it can on take off, seems to idle well but when I level off at speed it starts to break up real bad. I also have a new project bike which is a '83 gld that I'm gonna try to convert to a gk as I have all the fairing and bags for that. If anyone has a wiring harness to fit I could sure use one. The one on the '83 has been butchered pretty good. Thanks in advance, Joe

[Tarbash 27]

Start out and make sure your getting enough fuel flow. Any inline fuel filters can slow down the flow of gas. Next I would check the petcock to make sure its flowing like it should. It only flows fuel when you have vacuum from the carburetors. Also check that vacuum line. Go from there.

[tkent02]

Start out and make sure your getting enough fuel flow. Any inline fuel filters can slow down the flow of gas. Next I would check the petcock to make sure its flowing like it should. It only flows fuel when you have vacuum from the carburetors. Also check that vacuum line. Go from there.

If it can run well wide open it's getting enough fuel to run at low power, check the pilot circuits. Little blob of goo in there somewhere? They could be adjusted incorrectly. They are set as lean as they can be from the factory, a little intake air leakage or fuel blockage will make it run too lean to run correctly at low power, has no effect when you open up the throttle.
Plug chops should tell you what you need to know.

[racejunky]

you may have to dumb it down for me a little. Pilot circuits? and chop plugs? I may know what you are talking about just not that nomenclature, maybe?

[Steve]

I also have a new project bike which is a '83 gld that I'm gonna try to convert to a gk as I have all the fairing and bags for that.

You may end up with a dressed-out GL, but I am afraid that you will not turn it into a GK.

How long has this been happening? Did you just get the bike and have no idea of its history, or has it been running fine and just started acting up?

Either way, it sounds like it's time to clean the carbs. There is a good carb cleaning guide (<-- click on the link) in the garage section of this site. A good carb cleaning and then synchronizing the carbs will do wonders for how your bike runs.


.

[nert]

I have no answers, i have questions.
You have a manual choke on there. Apply choke while it is breaking up.
Does adding choke make run better or run worse?
Is there a difference between cold engine and hot engine performance? (that is not a yes or no question)
By "crapping out", do you mean effluent substance starts to emerge from open orifices? OR backfire through carburetors, backfire through exhaust, surge, ping, stall, non-responsive, erratic, vibration, etc?

answer these questions, and hopefully i will have more questions.

[racejunky]

By "crapping out" I mean it misses real bad, no backfiring at all. Warm or cold no difference, has done it since I owned it and have no real history of bike. Haven't tried the choke thing.

[TheCafeKid]

Hrm? Timing advance stuck? Ive read in a couple manuals that this can happen. I dunno for sure.

[KiwiGS]

In my experience if an engine starts missing under load it is most likely (but not always) an electrical fault.
Check your coils, HT wires, plug caps, and plugs.
That said I agree with everyone elses advice as well.
Good luck

[nert]

KiwiGS
I think racejunky is saying the problem occurs under light load. It appears to accelerate very well, under load.

TheCafeKid
An 82' should have electronic ignition. The "advance" may be digital relative to RPM. I don't think there is a mechanical advance unit employed here.

Light load or level off is a condition of high vacuum, and relatively small throttle opening. Which causes little demand from either the ignition system or the fuel system. A misfire (thinking out loud) is a fuel charge that does not fire. As previously stated, is does not fire either because of not enough fuel, or not enough spark. (yes air and compression is part, but lets skip that for now) When ignition is insufficient, the unburned fuel charge usually ends up passing out the exhaust pipe and ignited from hot exhaust spent by other cylinders in the exhaust system instead of in the cylinder where it should occur. Resulting in combustion out of the cylinder and in the exhaust pipe. (backfire).

As KiwiGS stated, ignition can often shows its ugly head under acceleration, load, etc. Heavy acceleration puts great demands on an ignition system, that might otherwise work perfectly well under no/light load conditions. Insufficient fuel however, at low demands can cause misfire without backfire through the carburetor. If you study the operation of the carburetor, and its various fuel delivery systems per throttle opening, it may make sense as to why a greater throttle opening, (heavy acceleration) runs well and part throttle (level off) does not, and yet it even idles well. These ranges of operation depend on different "systems" with in the carburetor.

tkent02 may have hit the answer a lot sooner, and with great accuracy without all my mindless ramblings. That choke lever test may help solidify the tkent02 diagnoses.
Although i never experienced it, I think i am feeling it.

[posplayr]

nert

Nice analysis;excellent deductive reasoning. :-D Let's see what the real solution is. 8-[
Posplayr

[chef1366]

I would check the slide diaphragms for pinholes.

[nert]

Nice analysis;excellent deductive reasoning. :-D Let's see what the real solution is. 8-[
Posplayr

That usually blows up in my face.

[trippivot]

your description is too vague AND incomplete to distinguish where your problem truly lies. what you described goes against symptoms of the common problems.

if you have a good idle and good acceleration the light cruise is a given.

fuel?
timed ignition?
compression?
any 1 or a combination of possibly all 3 are the root of all running problems.


You are going to NEED TO BEGIN with NEW PLUGS AND FRESH GAS period.
or reevaluate the TRUE running condition of the bike to begin with.

be honest. I'm an expert. a little water in the gas is the only thing I can think of that comes close to what you are describing except a bad idle and black exhaust smoke are present together.

more good info needed. good luck bro

[nert]

No offense
but "I'm an expert" what does that mean?

and

fuel?
timed ignition?
compression?
that covers everything, can't be wrong there.

"if you have a good idle and good acceleration the light cruise is a given."
an expert, might consider that there are factors not yet discovered.
(need to always keep the mind open) Sometimes, wrong or right, doesn't make sense till the problem is solved. "Light cruise is a given" (i would love to work with absolutes) in this business, doesn't happen.

I agree, more info is needed. More testing is required. No confrontation. The field is still, wide open.