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R75/5 Replaced failing battery, now won’t start...

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Justin Handfield
(@justinh)
Posts: 8
Active Member
Topic starter
 

Afternoon all,

My ‘72 R75/5 died out on me randomly on the way home a few days ago. Got off, kicked it back to life (my starter hasn’t worked for a while now, still on the to do list...), and rode the rest of the way (0.1mi or so) home. Did some testing of the battery and decided it was shot, replaced it with a new one.

Fool that I am, I decided at the same time this would be a great opportunity to replace my suspect speedo cable. Did so pretty smoothly, throughout the process two wires (Brown power to the headlight and white line to the high beam indicator from the headlight’s high beam) snapped off at their terminals but were easy fixes. Buttoned it all back up, kicked it a few times and... nothing. Said a few prayers/curses, rechecked connections, tried kicking again and still nothing.

Pulled a plug out and laid it on the cylinder to test for spark, nothing. Reading up on this a bit, the coils should be getting power off a terminal on the ignition switch, right? I’m worried now I jostled something else loose inside the headlight can. Pop the headlight back out I took a closer look at the board and it’s rather messy, I think the attached photo is the terminal they should be tied to? Doesn’t seem to be up to the standards I’d have expected...

I guess what I’m looking for is suggestions on where to go from here; do I try to remove the ignition board and clean things up / probably end up replacing half of what’s in there? Is there some other (simpler?) wire I may have nudged? Do I start making my way through a full electrical system test?

Appreciate any insights!

 
Posted : 07/01/2018 18:05
Richard W
(@wobbly)
Posts: 2540
Member
 

I decided at the same time this would be a great opportunity to replace my suspect speedo cable. Did so pretty smoothly, throughout the process two wires (Brown power to the headlight and white line to the high beam indicator from the headlight’s high beam) snapped off at their terminals but were easy fixes. Buttoned it all back up, kicked it a few times and... nothing. Said a few prayers/curses, rechecked connections, tried kicking again and still nothing.

► The first rule is to ALWAYS go back and double check the work you just completed when there is an issue. The problem is most likely in the work you just did.

► You may be shorting out the entire system. BROWN is not power, it's negative Return (what most people call "Ground"), which makes it the exact opposite. WHITE is power to Hi beam and YELLOW is power to Low beam.

Hope this gets some ideas going.

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 07/02/2018 00:55
Justin Handfield
(@justinh)
Posts: 8
Active Member
Topic starter
 

Your advice was spot on, as if they didn’t drill this into me enough back in grade school, always double-check your work! Turns out when I put the timing cover back on I managed to snag the wire to the condenser, crushing it and unplugging it. I’m a little ashamed at how long it took to find it, but at least I’m back on the road! Back to the to do list now...

Thanks Wobbly

 
Posted : 08/20/2018 08:06
Richard W
(@wobbly)
Posts: 2540
Member
 

Simple oversights happen to the best mechanics. This is why you want to do your own work. Now you know it can happen and from now on you'll be extra careful when replacing that cover.

Congrats on the discovery and fix !!

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 08/20/2018 17:32

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