alternator wire harness repair or replacement

[Magman]

I am in the process of restoring my 1969 350 Mark 3. The alternator harness is disintigrated beyond repair above the top of the engine case. I was hoping to repair it and spare myself major engine disassembly including trying to solder up a new wire harness at the stator coils. I have the 2 yellow and one red wires. The insulation just crumbles off the 3 colored wires under the heavy black insulator. Even the bare copper wire strands are tarnished and oxidized. I am amazed I didnt toast the electrics riding around. It would not have held up much longer. I dont have any of the special clutch tools or pullers etc. needed on the left side. I dont think it would be a good investment for me at several hundred dollars (or more) for special tools I may only use one time. Are drawings available to make these tools? or rentals? I am not sure what options I have or which option may be an obvious best choice for me. I sure could use some help. Maybe all the special tools needed are available and reasonably priced? BTW, the engine is pristine inside the left engine cover. I may not even pull the head the bike runs so good. Its got an honest 6,000 miles is all.

Any thoughts most appreciated.
thanks
Steve

[Jordan]

Believe it or not, a common carpenter's claw hammer is a very good tool for removing the left side engine cover.
It fits in the oval hole for the clutch adjustment, butts against the clutch assembly, and levers off the cover at just about the perfect point.
Try it gently, and see if it works for you.
Another way that doesn't seem so "bodge" is to use an old brass plug in the cover at the crankshaft end. Drill a hole in it to receive a slide hammer rod. A slide hammer is a beautiful tool, not often mentioned though.

[Bevel bob]

The flywheel puller cost me £20 ,the only other tool I would think about would be to lock the clutch , I made one with some old plates.

[DewCatTea-Bob]

[quote= Magman ...
" The alternator harness is disintigrated beyond repair above the top of the engine case. I was hoping to repair it and spare myself major engine disassembly
The insulation just crumbles off the 3 colored wires under the heavy black insulator. Even the bare copper wire strands are tarnished and oxidized.
the engine is pristine inside the left engine cover.
Any thoughts most appreciated. "

____ I've found that inside there, the rate of such decay is about a decade or more behind that which you've discovered outside of the engine. _ So there's a fair chance that you might be able to (at-least temporarily) get-away with not having to complete all the more extensive work which you wish to avoid, that's otherwise involved.
Still though,, the involved repair-work wouldn't be too awfully easy to perform, as you'd have-to feed a new replacement alt.cable through-into the inside of the motor, and CAREFULLY splice it to what you can salvage of the internal-section of the original alt.wire-leads, at your best possible location (outward of the remaining-installed alt.rotor).
__ Before jumping-on this idea however, you'll have-to carefully* check to determine if the individual wire-leads (within the black-rubber wire-conduit) are still up-to being handled for the splicing-work. _ (* Any non-careful handing may quite possibly unduly cause unnecessary insulation breakage.)
But even if that wire-insulation (that's been better protected) is also ready to crumble into particles,, if you're very careful, you could possibly make your splice-connections without any exposed wires being left to make contact with one-another (near that point of repair).
__ And even if the wire-insulation within alt.cable-conduit has also become ready to crumble to pieces, it's bulk-material will still remain in place to continue holding the bare wires separated apart, (so long as the alt.cable is left in place, ant not over-handled).
So this rather cheating-method of dealing with this particular common-problem,, may be worthy of trying-out first, before giving-in to the notion of fully doing a rather COMPLETE repair-job.
____ So let me know what you think of this possibility (for dealing with your situation).


Hopeful-Cheers,
-Bob

[Magman]

[quote="DewCatTea-Bob__ So this rather cheating-method of dealing with this particular common-problem,, may be worthy of trying-out first, before giving-in to the notion of fully doing a rather COMPLETE repair-job.
____ So let me know what you think of this possibility (for dealing with your situation).
-Bob[/quote]
My plan was to try a splice repair before I removed the left cover and had a look inside. there is nothing to loose by trying. Upon inspection there is no room to splice the harness without at least removing the clutch assy. I felt like I could splice and reseal the harness and build a new conduit maybe from a rubber hose of correct outer diameter and seal the inner diameter of conduit bearing up agains the 3 Alt wires. The challenge right now is that when I attempt to loosen the round conduit clamping nut on the top side of case, the conduit rotates and twists with the clamping nut causing the conduit to twist the harness inside the case. This is where I left off, put the cover back on and inquired here. The conduit is broken and swollen right at the jam nut into quite a mess. I could carefully disect the harness right at the nut in order to remove the nut I suppose.
It looks like there are at least a few special tools required just to remove the clutch assy to get proper access and maybe even a puller. My thinking is if I have to remove the clutch assy I may as well go all the way and replace the harness from the Alt. Perhaps this full harness repalcement is not such a rational approach even with the clutch assy removed and the splice is still a good option. I have never performed this disassembly so I am at quite a disadvantage to make a wise decision on my own. I am anxious to hear your thoughts on a splice repair so that I can weigh that option into the equation based on my ability and experience.
Is there a creative way to remove and reinstall the clutch, etc. without the special Ducati tools? It looks like I need 2 special wrenches? What else do I need to do a proper removal?

thanks- Steve

[double diamond]

You can remove the clutch hub nut with a pneumatic impact wrench. Removing the clutch requires no other special tools. You’ll also need the impact wrench to get the primary nut off. To tighten the two nuts you’ll need a clutch holding tool. I have a couple of these left from when I had some made for my own use if you decide to purchase tools. Or, depending upon where you’re located, there may be someone nearby who has the tools and would disassemble for you. It would only take a few minutes with the right tools. You must have a flywheel puller to get the flywheel off, but they can be purchased for as little as $50. Once you have the flywheel off, the stator comes off by removing a few screws. The alternator wire passes through what is basically a flare fitting where it exits the cases. There's a rubber gromet that the harness passes through. It's next to impossible to remove an old deteriorated harness from the flare fitting. You'll likely have to cut the harness off at the fitting. Also, it's pretty difficult to disassemble the fitting with out breaking the plastic nut.
Matt

[DewCatTea-Bob]

[quote= Magman ...
" when I attempt to loosen the round conduit clamping nut on the top side of case, the conduit rotates and twists with the clamping nut causing the conduit to twist the harness inside the case. "

____ You ought use that to your advantage for helping to cut-through the alt.cable inside there right-under the clamping/jam-nut as the cable twists & turns along-with the nut.



" The conduit is broken and swollen right at the jam nut into quite a mess. I could carefully disect the harness right at the nut in order to remove the nut I suppose. "

____ Yes, right,, and of-course that termination-point will help to keep the internal length of the cable as long as possible. "



" I felt like I could splice and reseal the harness "

____ Before splicing,, in case the wire-insulation is apt to crumble-off the cable's internal-wires (just-inward of the conduit-opening), you ought use a suitable blouse-button to feed the three wires through, so as to permanently hold-separated those conducting-wires apart from one-another, and then possibly squeeze-off a dab of silicone in-between for good-measure.



" and build a new conduit maybe from a rubber hose of correct outer diameter and seal the inner diameter of conduit bearing up agains the 3 Alt wires. "

____ There's already been a good number of thread-posts covering many optional avenues for replacing the stock alt.cable ! _ Perhaps you'd desire using one of them.
__ While my own preference is to build my-own alt.cable using stock-colored wires fed through suitable fuel-line, others rather hastily resort to making use of pre-existing PC.cords & the like, for a replacement-cable.



" Upon inspection there is no room to splice the harness without at least removing the clutch assy.
It looks like there are at least a few special tools required just to remove the clutch assy to get proper access and maybe even a puller. "

____ Actually, there's not a single special-tool "required" to dismantle a Duke-motor ! _ Although I'll admit that it's certainly best to have at-least a factory-type flywheel-puller.
__ To remove the clutch-hub nut,, after engaging the transmission into gear, all you need to do is sit a hard block of wood* on the floor of the motor-case and lodge it underneath a tooth of the drive-sprocket, so as to lock-up & hold the hub-nut from turning (as you wrench-on the nut).
This method can work for both loosening & tightening the clutch-hub nut (depending-on which side of the sprocket you place your piece of wood).
(* If your wood-piece is too soft, then you'll need to shift into top-gear.)



" My thinking is if I have to remove the clutch assy I may as well go all the way and replace the harness from the Alt. "

____ Well of-course that would be best, but pulling the mag.rotor/flywheel is a considerably tougher job than removal of the entire clutch.



" Perhaps this full harness repalcement is not such a rational approach even with the clutch assy removed and the splice is still a good option. "

____ I wouldn't say it's a "good" option,, however concerning all the other additional work, the rather simplified splicing-option may well be an adequate fix-option that's worth settling for (until there's also another-reason to further go so deeply into the motor).
Cuz if left undisturbed, the internal-length of the stock-alt.cable should continue-on keeping it's three contained wires all isolated, even if their aged wire-insulation also becomes brittle-fyed (like that of the exterior-length).



" I have never performed this disassembly so I am at quite a disadvantage to make a wise decision on my own. I am anxious to hear your thoughts on a splice repair so that I can weigh that option into the equation based on my ability and experience. "

____ Yes, of course,, that's certainly sound-reasoning.
And yet there's still more such equation-maters to consider in the mix,, such as how much time you have left before YOUR riding-season begins, and whether the rest of your stock charging-system is still functionally-operational as original.
Cuz if your stock regulator-unit has gone bad, then I highly recommend installing a FOUR-wire replacement-alt.cable (to go with whatever charging-system you may choose) ! _ And-so that would effectively compound the justification & need for replacing the entire alt.cable anyhow.



" Is there a creative way to remove and reinstall the clutch, etc. without the special Ducati tools? "

____ I've already explained how to loosen the nut which retains the clutch-hub & drum-basket,, and if the crankshaft-nut is also to be removed, then it could be done using the same suggested method, (but of-course before dismantling of the clutch). _ However, to help take pressure off-from the transmission,, a tightly wadded-up shop-rag could be stuffed in-between the primary-gears to help absorb some pressure off-of your chosen block* of wood.
(* When a suitably-sized piece of wood wasn't handy, I'd then rather use a (1&1/8th or 1&1/4th") socket-cap tool (along-with a scrap-strip of wood) to lodge under & against the drive-sprocket.)



" It looks like I need 2 special wrenches? "

____ I wouldn't say "need",, but if you go-onward & decide to pull the alt.rotor, then you'll certainly need a GOOD flywheel-puller.


Hopeful-Cheers,
-Bob

[JimF]

Bob is right on all points, of course.

I just want to add a +1 about holding the clutch still. You do not need a clutch holding tool. I use the wadded up shop rag trick.

As for special tools you will need an impact gun to get the nut holding the clutch off. Not necessarily air powered, I am fortunate that I can borrow a battery operated one from a friend to save the expense of buying one.

You will need the flywheel pulling tool though. They are not expensive.

I have seen both ends of the spectrum with regards to alternator wires in the cases. For an inexplicable reason I have seen wires that, sans UV rays perhaps, are in good shape and I have had wires whose insulation crumbled into powder to the touch.

Changing the wires out is only intimidating the first time, and getting fresh wires installed takes a load of legitimate worry off your mind.

[Magman]

OK, well, I sincerely appreciate the excellent suggestions from all you folks. I went ahead and ordered a flywheel puller off Amazon for $49 plus shipping...hard to beat that price for a needed special tool. I may pick up a clutch holding tool or Mke one from an old clutch disk. I have shop air and impact guns. I will use the rag method for disassembly. I will be busy for awhile just stripping the frame for fresh paint and quite a variety of other tasks before full reassembly of the clutch is necessary. I am in no hurry for riding season. I just picked up an 05 Road King and I have other bikes including an 04 Rune but nothing in the class that can hold a candle to the joy of a 200 lb Desmo. I was planning to keep the electrics all stock but now i am curious about the advantages of a 4 wire Alt setup. I am not such a purist that I need to maintain the original 6 volt Alt and Reg setup or the bakelite in the headlight basket. The Regulator is working OK but I am not sure all functions are working properly. I hot wired a new generic brake switch and tail light/ brake light so I could put some miles on the bike and determine condition before commiting to restoration. Perhaps I need to buy a new modern regulator or even consider 12volt operation. I have time to decide and hear some arguments. I am restoring the bike to ride and enjoy in memory of my father so reliability is my highest concern. Please tell me your thoughts on the 6V vs 12V as it applies to reliability and what units are of sound value.

Many thanks
Steve

[DewCatTea-Bob]

[quote= Magman ...
" I may pick up a clutch holding tool or Mke one from an old clutch disk. "

____ Is that because you haven't understood how locking-up the drive-sprocket & transmission could hold the clutch-hub & nut from turning, for you ?



" I was planning to keep the electrics all stock but now i am curious about the advantages of a 4 wire Alt setup. "

____ The intended advantage of the extra added alt.wire-lead,, is so that ANY charging-system components can then be chosen, including the stock-system !
So to replace the stock 3-wire alt.cable with merely-just such as the very-same,, would end-up being a handicap which could've been avoided, should it ever be desired to alter the stock charging-system in most ANY chosen way.
So that's why whenever replacing the entire alt.cable, it ought-to be done with a wire-cable that offers any advantage which helps make the installation-work more worth-while.
__ The Ducati-alternator has two separate power-coils of which they-themselves are electrically-isolated, (but purposely not magnetically-isolated),, yet Ducati's chosen charging-system with it's mere 3-wire alt.cable CONSTANTLY forces both of the alt.coil power-outputs to no-longer be left isolated, (as the 'common' red-wire has-to handle BOTH power-outputs).
With a 4th-wire added,, there's then two-pairs of alt.stator wire-leads, one pair for each alt.power-coil so that access to each power-output can then be done separately (for a charging-system which can take advantage of COMPLETELY electrically-separated alt.power-outputs).



" I am not such a purist that I need to maintain the original 6 volt Alt and Reg setup "

____ The addition of a 4th-wire setup, does-not mean that any stock electrical-function has to be changed !



" The Regulator is working OK "

____ But should it ever come to break-down & fail, ya wouldn't then want to be stuck having to find another-one that's still working. _ (There are no other regulators available which work exactly the same-way as Ducati's.)
So better to already be ready to go-with whatever replacement you may happen to end-up with.



" Perhaps I need to buy a new modern regulator "

____ Since your stock-unit is working, I really don't think you "need" to do so.



" Please tell me your thoughts on the 6V vs 12V as it applies to reliability "

____ Reliability itself is-not much of an issue between the two, however wiring-connections are certainly somewhat more reliable with handling the inherently reduced current of 12v.systems.
But that's not much of a real concern with a stock load-system (with it's mere 25 to 35 watt headlight).


Hopeful-Cheers,
-Bob