Gs550 1979 led blinkers flash erratically

[Ratboyollie]

Hey guys,




I’m running in to a electrical gremlin and cant seem to figure out why it is doing this.




some info:

- fresh rebuild engine

- custom wiring harness (used the same setup before rebuild, also on another model)

- Flashers work great without engine running, when the engine runs the flashers act erratically.

- had it wired before with stock relay and risistors this worked fine.

- speedometer backlight broke when testing engine?

- wiring harness gets power from modern blade fuse block, power from battery to key to fuse block thus powering bike.

- reg/rect puts out 12.8 at idle and about 13.8/14 at higher rpms

- red reg/rect wire goes to battery, white/red wire not used (tested with multimeter, doesnt put out voltage? I dont use this on other builds as well)

- coils are 650 and tested good, spark is good also.

- power to led relay (also used on other builds) is 12 ish (depending on battery life) when engine off. About 13 when engine is running (fluctuating on rpms). Also tested without the reg rect connected, no difference in flashing.

- led relay switched out with new does not make a difference.

- resistor caps and non resistor plugs.

- tested with ground cable from ground battery to engine- no difference.


Some thoughts i’m going to test:

• could this be rfi/ emi interference from coils/ plugwires/ plugs?
• Power backfeeding in to the system?
• Too much power for the relay?
• Ground issue?
• Ac voltage getting in the system
• Not enough load on the system

Any input is welcome

[Ratboyollie]

Found the following:

Stator = good
ground = good
reg= good

Coils 4.3 ohms on the mains and 15k ohms on the secondarys. Manual says spec is 34/36k ohms between plug caps. With 5k resistor plug caps i get 25k ohms. I’m going to order the dr8es sparkplugs and see how that goes, this would equal 15K+10k(r)+10k(r)=35k ohms resistance

[phydeauxmutt]

If that is a stock R/R, the white/red wire is an INPUT, and should be connected to a similar wire from the stator.

[Ratboyollie]

You’re right, thanks, i was checking over the wiring diagram and have mistaken it with a honda one. On the honda one it is for driving light and suzuki it connects to the green/ white wire from stator.

i did check it yesterday if it made any difference but nothing for the blinker issue.

[pdqford]

Hey guys,


- Flashers work great without engine running, when the engine runs the flashers act erratically.

- had it wired before with stock relay and risistors this worked fine.

What has changed?

Might be time to fire up the amp clamp and measure the amp load going through the flasher with and without the engine running.

I would also try running the R/R output directly into the harness load instead of to the battery + post. Could just be that the battery draw AND the engine draw isn’t leaving enough current to reliably power the flasher.

Have you checked for ripple in the R/R output?

[Ratboyollie]

What has changed?

Might be time to fire up the amp clamp and measure the amp load going through the flasher with and without the engine running.

I would also try running the R/R output directly into the harness load instead of to the battery + post. Could just be that the battery draw AND the engine draw isn’t leaving enough current to reliably power the flasher.

Have you checked for ripple in the R/R output?

I have not checked the ripple nor the amps, i will do that, thanks! I did however disconnect the r/r and stator and did not make a difference (this would eliminate ripple and output right?)

what changed is:
-The Kokusan ignition had the wrong condensers i swapped these out to the right ones (I checked if its not shorting out on the engine, but will check to be sure).
- i had the oem flasher relay wired with resistors before. flashers did work then, but it was kind of messy. I had some weird elec stuff happen then, diodes going out fast.

i’m fairly certain not enough resistance between the coil and the plug is the problem. It seems like when the spark happens it affects the flashing. I read some other post about not enough resistance/ faulty sparkplug wires having similar problems.

i’ll order resistor plugs and let you know how it goes

[Ratboyollie]

Resistor plugs save the day. Everything working perfect now!

[ItsBork]

Resistor plugs save the day. Everything working perfect now!

hey man just wanted to let you know this solved my problems as well! i was having erratic flashing with led signals and my lights strips were cutting out even after swapping out the relay and doing a diode mod and an SH775 swap. I swapped my plugs out for resistor plugs and it all cleared up! Thanks for updating with your solution