In working on a pal's R75/6, one of the needed repairs was the positive battery terminal cable replacement. The cable showed signs of having been re-terminated at some point in the distant past, so the cable was now too short for the new battery. As one might expect, there was lots of terminal corrosion at the battery end.
When I got the cable off at the starter end, to my great surprise, the corrosion for the battery acid had wicked up the entire length of the cable and was puking out onto the starter terminal !!! This cable is nearly 28 inches long ! Since this one cable supplies all the positive termination between the battery and electrical system, if the connectivity goes out, then the entire electrical system will go down. Although you could jumper this out on a /6 and kick start, the task becomes much harder on a /7.
I have never seen anything like this in all my years of car and motorcycle maintenance. Additionally, being the preventative maintenance type, it means my bike has to get the same treatment, or at least a closer inspection
So, besides reporting this unseen time bomb to the group, my question is do others generally build their own cables or simply use the BMW replacement part ?
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Wow. Never heard of this one before.
I am rebuilding a 76 R90S and from what I can research, it's good insurance to replace the stock cables with an upgrade, available for about $50.
Check one of the suppliers in the Airheads mag...sorry, don't have a copy handy with me, or google it.
I ended up buying a 60 inch starter cable (with 5/16 eyelets on each end) and cutting it in half, since 30 inches seemed to be the correct length. Then I soldered on a 1/4 inch eyelet. Both these items were from Tractor Supply Co.. (With 4 AWG cable, that takes a lot of solder !) Then I sealed the acid out of the new cable by applying red adhesive heat shrink over both ends. I found that at a local auto parts store.
The red color certainly makes battery connection fool-proof too.
🙂
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
When I restored my R90 I made several new cables for the bike, re-worked many of the old ones, replaced by UP-grading several to circumvent issues and provide the operation I want, where I want it ........ without issues.
TBS, i replaced my main starter cable and it cost me what the ends cost me, a little work and a happy camper to boot. many of you live where there is an auto stereo installation type dealer. they have awesome cable .... scraps, usually for cheap or free. i picked up several feet of 4 gauge, multi stranded high performance cable ... free.
so the new grounds are in along with power to the AGM battery.
double ground wires to the tranny case bolt using a longer allenhead and spacer, star washer and NEVER need to touch the Vent bolt again. the second battery ground goes to the right side coil lug.
ALL cables are crimped using a proper TOOL, soldered and heat shrunk. EVERY wire attachment has a STAR washer to help provide positive contact to bare metal, then coated for corrosiveness.
I love your ground cable attachment upgrade! That is pure genius.
I have considered routing mine to one of the starter mounting bolts, ala automotive practice, by going in through the starter cover air intake. It would make it difficult to remove the cover, which is the only reason I haven't done it yet.
And I'll have to go dumpster diving behind my local car stereo outfit too!
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
4 ways I ground my work, plus case bolts should do it. when you need to work on the bike ...... remove the BATT 2 wires to clear issues
1. Frame to starter motor triangle, braided wire,
2. BATT to Coil lug rt side, ............... #6 (monster) wire , another
3. BATT to tranny back case bolt, (shown) #8 (monster) wire
Standard wire harness to left side coil frame,
4. from the starter triangle mount plate thru and to the engine front diode case bolt #16 wire. i have several others, the H/L shell is fully grounded by it's own 16ga wire,
EME Rectifier/ Reg'r has it's own ground wire . . . . . . . . and more
NEVER USE the Trans. Vent bolt! !
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