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Starter Relay FXR

Started by hogpipes1, October 16, 2023, 03:07:37 PM

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hogpipes1

I  picked up a 86 Fxrc barn find sitting sense 2014. Fresh gas , battery to start with. Fires up a few times then click click click. It's  the start relay.
 I have a few in parts dept. Put a new one in fire's up and issue taken care of.some of my relays have a diode in the circuit terminal 85-86.I have a good fact sheet on the different between with &  w/o the diode in the relay. Can't find the lnfor.right now. So I need a update on any issues using either one ? This FXR had the relay w/o a diode
THANKS.
 


 

hattitude

#1
I am an electronically challenged person. But I can usually follow directions and/or advice..

Here's what I was told..

With the older HD relays, the system relay had a diode, the starter relay did not.

The system relay with a diode, dissipates the voltage spike when the relay is shut off, from back flowing into the circuit and damaging any sensitive electronics like the TSSM/TSM or ECM on EFI bikes.

Apparently that isn't a concern within the starter circuit.

As long as the relay is properly rated for the circuit's amperage, having a diode doesn't hurt anything... but NOT having the diode in a circuit with sensitive electronics, could cause an issue.

I was told for testing purposes, swapping relays is OK, but don't leave a starter relay in the system circuit for longer than necessary to test if the relay is the problem.

If I am remembering this wrong, or was givien poor info.... I welcome any corrections..


I did a quick check and it seems the replacement relays for the #31506-79C starter relay (original is unavailable) all seem to have a diode in them now. Based on what I was told, this shouldn't cause a problem as long as the amperage rating for the relay is correct..

smoserx1

Yes that is my understanding too.  The diode is only required to suppress the backfeed where the backfeed would damage an electronic device like an ECM.  A diode or standard relay can both be used anywhere a regular one was used such as in the starter circuit where the backfeed would not matter.

hogpipes1

A little late getting back.Nothing fancy in the start circuit to need a diode,but the new one has it and good to go.Always get the right info here.TKS.