1973 R75/5 - electrical issues?

[srankin]

The first couple of years of the /5 bikes I believe didn't have fuses? St.

[cbclemmens]

St.

Both my '71 R 75/5 (my current ride), and my 72 (which I bought new) have fuses behind the headlight. I'm sure a 73 would have them as well.

Craig

[drpetemurray]

St.

Both my '71 R 75/5 (my current ride), and my 72 (which I bought new) have fuses behind the headlight. I'm sure a 73 would have them as well.

Craig

Wow Craig!
Not to get off topic but very cool that you not only purchased your 72 new but it is in your possession.

[Wayne J in MA]

My ‘71 (late 70 build) did not have fuses. I added them back in the 70s.

[cbclemmens]

Pete

I didn't mean to mislead, but the '72 is no longer in my possession. I only wish it were.

Craig

[Kidasters]

Update -

I decided to check some more things before pulling the board out of the headlight bucket. Opened up the fuses, and the 25 amp fuse was blown. Hoping that this was an easy fix, I got out another fuse and installed it. No joy - and that fuse is instantly blown. Checked the other fuse and it was fine (replaced it anyway with a new one).

If I read the wiring diagram correctly - that fuse is between the coil and the starter relay. Maybe start with replacing the relay?

Just removed my tank and realized that I have a Dyna electronic ignition. Still going to replace the relay, but may have other issues.

Thoughts?

[Kidasters]

ok - may have solved it.

Ordered replacement relay for the electronic ignition, but while I had the tank off, measured resistance across both coils. One is rock solid at 1.7 ohms. that's the right side coil. Left side coil - where the green wire goes - jumping all over. Gotta be a bad coil. New coils headed on the way. While I'm there, I'm going to clean wires and grounds.

Hopefully this solves it.

[srankin]

A 25 amp fuse? I am going out on a limb but isn't that high? LOL, I am used to 8 amp in the other bikes so, forgive any misunderstanding regarding the /5 set up. St.

[Kidasters]

ok - it's probably not 25 amp. It's the blue one marked 25. That's what was in there anyway. Probably yet another Previous Owner thing that I'm finding.

I think you are right. 25 is too big for as small as those wires are. I replaced it with an 8. Good thing I have lots of those laying around.

[Kidasters]

The other thing I'll do while I have access - I'll add a charging pigtail to this bike's battery, as well as my 78 R100. Just that much easier to connect them to the trickle chargers.