Bike dying when using turn signals

[mcquillr]

Hi All,

At first I wasn?t really sure where to post this since it seems to be a fuel/electrical combo situation.

I just got my 1977 GS400X running again after it was sitting for a few years. I live in the city and don?t have a place to work on it so I ended up taking it to a shop to bring her back to life. The guy that looked at it said it was still in pretty good shape so all he really had to do was :

1) Carb cleanup
2) Dress and adjust points
3) Set timing
4) Check valves (0.003)
6) Change oil
7) New battery
8) Clean plugs
9) Replace air filter (installed pods, see below)

The bike runs pretty nicely however I noticed a problem when the bike is ideling.

The bike typically idles comfortably around 1300-1400rpm however, when I put on a turn signal the idle begins to dip (like a hiccup) and in some cases it will cause the bike to die (requiring a fast kick start in traffic).

If I put the turn signals on and then turn them off when the idle beings to dip, it returns to normal (his is very reproducible).

I understand that these bikes have some stator issues however I?m not super, super familiar with them. I did check the battery and it holds a charge. When I rev the bike the voltage rises. The bike functions normally during higher-speed riding.

Okay, here?s the second part (the part that made it hard to decide which category to put the problem in):

A few years back when I was riding regularly I put shorty pipes on the bike but didn?t reject the carbs (this didn?t seem to make much of a difference). However, my mechanic now installed pods and insisted that I didn?t need to rejet my carbs. This seems a little odd to me since it seems to be a rule of thumb than when you mess with air/fuel mix you usually need to rejet.

Do you guys think this an electrical problem, a fuel/idle problem, or both?

Any insight would be greatly appreciated.

 

[Cipher]

is lectrical is stator or regulator related.
I have had this hjappen to me when a battery was marginal due to a weak charging system.

You have a meter? Dont need a fancy fluke just about anything will do.

 

[Redman]

Sounds like turning on the t/signals is enough of added load to drop the voltage to where the ignition is barley working. But that should not happen if the charging sysgtem is working enough to keep the battery at a good charge.

And... as with most eletrical problems, you need a volt meter (multimeter) to check out the charging system.

Check battery voltage with key off, then with key on, then bike running at idle, then again at mid rpm (like 4000).
List the results here.

 

[mcquillr]

That makes sense to me as well. I will check these volatages tomorrow and post em up. Thanks!

 

[Redman]

Here is a better description of the "Quick Test"
https://www.thegsresources.com/_for...rging-System-QUICK-TEST&p=1272192#post1272192
as developed by Posplayer

 

[mcquillr]

The test results are in:

Key Off (Pre-start): 12.57V
Key On (w/lights 10s): 12.25V
1500rpm (idle): 13.76V
2500rpm: 13.39V
5000rpm: 13.52V
Key Off (Post-test): 13.36V

 

[Cipher]

the battery is somewhat depeleted at rest.
You should check the bulb sockets mine love to corrode being madde of a chromated cheap metal
also check the connectors to the harness the bullets are evil and get loose with repeated removals
they build up a thickish layer of tarnish as well
if a check and or clean of connections and sockets makes no difference well then clean the switch. AN amazing amount of dust can get packed in there giving you three contact points of cumulative resistance overall.

 

[Redman]

The test results are in:
...........

Charging system is working, could be a little better, maybe some bad connections here and there. But good enough to mostly charge the battery and keep the bike running. Not bad enough to explain the bike stalling when use the turn signals.

Bike stalling when use the turn signals sounds like low voltage to the ignition.
Try measuring voltage at the coils (the org/wht wire). Will have to have the tank off to get access to that.

 

[mcquillr]

Okay good thinking!

Redman: I will test the voltage at the coils this weekend and report back.

Cipher: I will check the bike up-and-down this weekend for loose and/or dirty connections & switches and report back.

Thanks for the advice!

Question: Should I think about changing out my R/R to a series R/R as a preventative measure? Also it was suggested in the Top Ten Newbie Mistakes thread that you should re-route the headlamp switch leg back to the R/R to prevent stator overheating. I imagine this is referring to the day/night paths in the pre-1978 charging system diagram in the Clymer manual?

 

[Guest]

I would suggest that you check the fuse box and make sure the contacts holding the fuses are clean. feel for heat on the fuse box, this will tell you if you have a bad connection in that circuit.

 

[Guest]

Hi All,
A few years back when I was riding regularly I put shorty pipes on the bike but didn’t reject the carbs (this didn’t seem to make much of a difference). However, my mechanic now installed pods and insisted that I didn’t need to rejet my carbs. This seems a little odd to me since it seems to be a rule of thumb than when you mess with air/fuel mix you usually need to rejet. Do you guys think this an electrical problem, a fuel/idle problem, or both? Any insight would be greatly appreciated.

If he installed pods you need to re-jet but only after you fire your mechanic. Exhaust is not so bad but pods change everything! Your bike should idle at 1,000RPM. It seems you have more than one problem.

 

[Redman]

Good that you have reviewed the Top Ten Newbie Mistakes information.

............
............... should re-route the headlamp switch leg back to the R/R to prevent stator overheating...............

That is a recommendation for 1980s and after bikes (dont have the headlight on-off switch). I think your 77 will have the headlight swtich, and if you do want to retain the headlight swtich you will want to keep the wiring in the stator circuit up to the headlight switch and back.

 

[mcquillr]

Good that you have reviewed the Top Ten Newbie Mistakes information.


That is a recommendation for 1980s and after bikes (dont have the headlight on-off switch). I think your 77 will have the headlight swtich, and if you do want to retain the headlight swtich you will want to keep the wiring in the stator circuit up to the headlight switch and back.

Actually, I don?t have an on/off switch either?only a hi/lo switch. There seems to be a hard piece of plastic that acts as a placeholder for where an on/off switch would be.

 

[mcquillr]

I would suggest that you check the fuse box and make sure the contacts holding the fuses are clean. feel for heat on the fuse box, this will tell you if you have a bad connection in that circuit.

Added this to the list!

 

[mcquillr]

If he installed pods you need to re-jet but only after you fire your mechanic. Exhaust is not so bad but pods change everything! Your bike should idle at 1,000RPM. It seems you have more than one problem.

You are correct that it will not hold an idle at 1000rpm. I currently have the idle set between 1300-1400rpm (I though I saw this as the correct range in the owner’s manual, but I don’t have it in front of me to check that).

Okay so if my limited intuition is right, pods would increase air flow and lean out the mixture so I should be jetting up to increase fuel? Is there any rule of thumb with re-jetting or is it simply trial and error?

 

[Guest]

I was posting late. Idle probably should be about 1,200RPM. My bike will idle at 900rpm but that is too low so I set it at about 1,100RPM. I have no experience with totally uncharted waters. I have always used a Dynajet kit to get me in the ball park. You also need to have quality pods to get consistent results. I am also familiar with the VM carburetors. Parts lookup shows CV carburetors on your bike (I didn't even know they had CV carburetors in '77) So please wait for someone else to chime in that has that experience. Your mechanic probably changed you over to pods because he was too lazy to want to fool with the air box, that can be a real PITA. I imagine you will need main jets that are two or three times larger than what you have. Too lean a fuel mix will cause the motor to run too hot and possibly cause permanent damage. You need to become your own mechanic. There are more than enough people on this site to teach you how to do it correctly. I would certainly get your old air box back if you can. They can be sealed and the boots softened if they have not been damaged and are just hard.

 

[mcquillr]

OldVet66, yes I am definitely trying to become my own mechanic. I am eager to learn!

 

[Guest]

You might have more luck posting this part of your post on the carburetor/exhaust forum and get the carburetor problem out of electrical where it might get buried.

 

[850 Combat]

I would agree with Redman. It is charging, but not enough.
I would add a ground from the battery to the R/R ground to the frame as a matter of course.

I would also consider the coil relay mod to make sure full voltage is routed to the coil. I never have used that mod, because over years, I have determined that relays, like connectors, are not my friend. I've found that improved grounds can turn a 13. something weak charging system into a 14 volt charging. That said, almost every GS I have purchased had a weak 13.0 to 13.6 volt charging system, and none exhibited any kind of problem what so ever. Without testing, I would have never known, as there were no symptoms. Look for signs of overheating at the three main stator connections and the main red wire off of the R/R. It will be there. Grounds and cleaned or eliminated connectors should help. I like solder and shrink tubing instead of overheated connectors.

 

[Guest]

On the electrical side of your problem you have already gotten good advise. I would start by cleaning and shining up the inside of your turn signal bulb sockets and coating the surfaces with dielectric grease. The turn signal switch would be next, but please disassemble it in a very clear plastic bag. There are all sorts of springs and tiny parts that can go flying and lost forever if you don't. Clean up the switch contacts and coat with dielectric grease. DeoxIT is an excellent contact cleaner. That will probably clear enough high contact resistance to keep the bike from stalling when you use the turn signals. When you can, every switch, especially ignition and kill switch, needs the same treatment along with every connector, plug, light and the fuse on the bike. Look at all your grounds. Star washers help with all those connections with ring terminals on the bike. This may cure your charging issue or at least correct all the high contact resistances that have developed over the years. The coil relay mod is not a bad idea, but is a work around for poor electrical connections. You may uncover wire terminals that need replacement but this is a good thing. Good luck!