RPMs increase and decrease with blinker?

[Cipher]

As far as the carburetor issue goes, which I think I also have a carburetor problem, because the bike will not throttle up whatsoever when I engage the throttle.

The carburetor has been cleaned and rebuilt, and all the jets and airways have been tested with carb cleaner blowouts. Needle jet diaphragms are going up and down nicely.
Idle and choke are both working well. I have new gas going through an inline filter. I tested for air leaks with some break cleaner. Petcok and float valves are working and flowing, hence a great idle for extend amount of time.

The only issue that I can see right now with the carb is that it does not have a pilot jet “plug”. There is even a housing for this pilot jet plug on my carburetor. A plug would fit right in it. It looks like it is designed for a plug. BUT, the parts specs for the GS300L doesn’t have any mention of a plug, even though the GS450 had them. Other than that everything is working fine!

I don’t know if the electrical issue is messing with the carb throttle up. I wouldn't think it would. The carb has no electrical hook up to it. It’s a different system, right?

Do you think this bike has an electrical connection that goes from the throttle to the ignition system? Something that tells the bike to increase the spark? I did not see any in the service manual.

clean the grounds and put on the pipes and airbox\filter

[rphillips]

Very interesting, just can't imagine anything electrical making the revs go "up" on these old bikes. Wondering how much the revs rise when brake light comes on.

[pdqford]

and yes, the engine will rev up when I engage either the front or rear brakes.

Sorry, that’s not what I was trying to get at.
To use your terminology, I should have asked if the engine will “throttle up” when the brake light is on?

(Thinking you may have a marginal shared ground that is reducing current to the coils, but the ground improves with more current (i.e., brake light current) added to the ground. Any loose or cruddy grounds? Do you have the wiring diagram?)

[rphillips]

No doubt grounding problems can cause all kinds of strange things to happen. but changes to the coil ground or brale light making the rpm rise or throttle response better, I'm missing it.

[pdqford]

I am grabbing at straws, but thinking if the brake light sends more current through the shared ground, that may improve the current through the coils.
That’s why I am curious to see what the coil voltage is before and after the brake light comes on.

[rphillips]

All things possible. Will be interesting to know, if not this, what cause is... Kentman, does anything happen different if twisting the throttle with brake on or brake off?

[Kentman7]

Sorry, that’s not what I was trying to get at.
To use your terminology, I should have asked if the engine will “throttle up” when the brake light is on?

(Thinking you may have a marginal shared ground that is reducing current to the coils, but the ground improves with more current (i.e., brake light current) added to the ground. Any loose or cruddy grounds? Do you have the wiring diagram?)

Yes. The engine does throttle up with either the front or rear brake engaged.

I’ve been combing through the service manuals for any type of wiring diagram. Not too much luck. I don’t know what I’m looking for, so it’s difficult.

that’s the thing. All the wiring is in great shape. Nothing has stuck out to me. Obviously I’m missing something.

can you post videos to this forum? Or just pictures?

[Kentman7]

I will check the voltage at all those points in the next few days.

I will check back here for the results.

[rphillips]

Let ma ask this way, When you push the brake, does the eng. rpm. go up automatic, without turning the throttle? Or after pushing the brake do you got to turn the throttle to get the rpm's to go up? Also while pushing the brake, does turning the throttle work as it should, can you turn it and make rpm go to 3K or 4K rpm.?

[Kentman7]

Let ma ask this way, When you push the brake, does the eng. rpm. go up automatic, without turning the throttle? Or after pushing the brake do you got to turn the throttle to get the rpm's to go up? Also while pushing the brake, does turning the throttle work as it should, can you turn it and make rpm go to 3K or 4K rpm.?

Yes. When I engage any of the brakes, blinkers, high beams etc. the engine RPMs go up without engaging the throttle. As far as the blinkers ago, when the blinker flashes on the RPMs go up, I’m with the blinker flashes off the RPMs decrease.

At no point does the throttle on this bike work. At no point does the throttle increase the RPMs, No matter if the brake system is engaged or not.


The bike will idle perfectly.

[Rich82GS750TZ]

I am fascinated with this thread. Cant wait to find out how this is resolved.

[pdqford]

I am fascinated with this thread. Cant wait to find out how this is resolved.
[/img]

^^^^^^
Me Too! .

[Burque73]

I will check the voltage at all those points in the next few days.

I will check back here for the results.

Looking forward to seeing your results.

Is the charging system all stock still? Maybe any load on the electrical system causes the voltage regulator to let too much current through overloading the system. It is common for the regulatorsto fail, but usually results in a cooked stator and overcharged battery, not what you're describing.

[Cipher]

Yes. When I engage any of the brakes, blinkers, high beams etc. the engine RPMs go up without engaging the throttle. As far as the blinkers ago, when the blinker flashes on the RPMs go up, I’m with the blinker flashes off the RPMs decrease.

At no point does the throttle on this bike work. At no point does the throttle increase the RPMs, No matter if the brake system is engaged or not.


The bike will idle perfectly.

Find the grounds and clean them. pg 224 of the FSM Wires amy also be damaged. There's a section in some harnesses used on GS bikes that have several wires spliced roughly with steel ( by now rusted ) clips.

Also is the airbox filter and exhaust installed? not directly related to the weird electrical issue but a much needed reality.

manual is here https://gsarchive.bwringer.com/
the wiring diagram is inside and yes they are had to follow but it seems the bike is using the signals presumably sufficient ground when the circuit is closed.

[pdqford]

Yes. When I engage any of the brakes, blinkers, high beams etc. the engine RPMs go up without engaging the throttle. As far as the blinkers ago, when the blinker flashes on the RPMs go up, I’m with the blinker flashes off the RPMs decrease.
.

How about if you press the horn button
Do the engine RPMs go up?

(The black and white wiring diagram makes my eyes hurt,
but I think we are chasing two separate issues.)

Why is there what I would call a "jumper wire" between the headlight ground wire and the front turn signal lights ground wire, since those two ground circuits already meet up after they pick up the ground side of the horn switch?

Interestingly enough the R/R and the Ignitor box are spliced into this same ground wire!

AND this ground wire is spliced into a wire, of which EACH end goes to a ground!

I gotta rest my eyes, but one more question:
What is the difference between a ground symbol where the little dash lines of the ground signal form a triangle and those that form a rectangle?