suggestions for bad pickup coil

[DavePlum]

I have discovered one of my pickup coils on my 80SG project is bad because of a bad wire. When I was removing the timing cover I noticed not one of the four hex head screws were even slightly tight and once the cover was off I could really see the effects of long term exposure to the elements in the form of corrosion. I've only had the bike since the end of July and keep it in my garage so this would be the work of the PO. While checking resistance in the pickup coil wires I discovered that when I manually turn the pickups counterclockwise they stick in that position and don't return unless I manually move them. I also noticed when turned I get acceptable readings on both pickup coils but when it returns the ohm readings shoot way high one coil (into the mega ohm area and bounce around) on one of the pickups and the other remains steady.
Questions:
1. Is there anything else besides the return springs that might cause the vacuum advance to not return?
2. Can the springs be cleaned up or replaceable?
3. How difficult is it to replace the entire assembly on a 80SG? Mine has the bolts that have to be drilled and removed with an easy out.
4. I have a 79SG engine with good pickup coils and vacuum advance moves and return freely, should I just put the 79 coils on the 80?
Thanks, Dave

[jetmechmarty]

I'm not positive, but I believe the '79 has a different advance curve than the '80.

I have an SG and I've had it apart far enough to lube everything up and get it properly functioning.

The pickup coil wires are the Achilles heel of this machine. You'll have to splice in some flexible replacement wire. Some have used meter leads.

I recommend using 1/4 in long uninsulated butt splices.

Cover with heat shrink.

[motoman]

As jetmecharty suggested, if one of pick-up coil wires are broke internally(pulling on insulation every inch looking for insulation to stretch), the butt connector he has shown needs to be way shorter. Slip a small piece of shrink tubing over wire after cut. Crimp on the really short piece of butt connector, and slip piece of shrink tubing over connection repair and shrink it......done.

[kboehringer]

100% Silicone Wire Covering

SNIP... I discovered that when I manually turn the pickups counterclockwise they stick in that position and don't return unless I manually move them.

Dave that assembly has a large shielded precision bearing. It is not a SEALED bearing so soaking it with light oil (machine tool oil) will loosen it up. I had one act similarly until it was oiled and worked in a bit. Only one of the several bikes/XS11 motors I've purchased had the required cover gasket in place. All of my active bikes have that gasket!

The pickup coil wires are the Achilles heel of this machine. You'll have to splice in some flexible replacement wire. Some have used meter leads.

I've used meter leads for repair of mine. Marty's instructions are 100% spot on! The key is 100% silicone wire covering (which meter leads typically are) which makes for an incredibly flexible wire. I purchased a small roll of wire with 100% silicone cover from Grainger.

[jetmechmarty]

You can buy those butt connectors 1/4" long. My local True Value Hardware has them.

[DavePlum]

Thanks for all the responses and suggestions. Thanks for the heads up on the difference between the 79 & 80 timing curve. Even if it was doable I wasn't looking forward to swapping the entire assembly out.
Using the (pull wire look for stretching method) I found exactly where the break was. Once I had cut back the insulation I held the bare ends together and my meter read 750 ohms at the TCI connector. Turns out it was the white wire.
I also applied some oil to that bearing and it already turns much easier but still does not return if I turn it all the way. Anyone know how many degrees it normally moves? Before I applied the oil it would only move a few degrees would be a bit squeaky and stick, it now the squeak is gone and it moves about twice as far before it sticks. It only fails to return when I move it full travel, if I go 90% of full travel and it will return fine. Hopefully it will begin to consistently return after full travel as the oil soaks that bearing.
I also went ahead and checked ignition coils (primary and secondary both within specs), I also checked the emergency kill switch and it checks out fine as well.
Hopefully I can get that wire fixed tomorrow using wire leads from a DVM and give an update. btw...I have a talent for breaking off DVM leads so I have plenty of wire.

[DavePlum]

UPDATE: (For those who might be the least bit interested)
I was able to repair the white wire going to the pickup coil using dvm lead wire and butt connectors and it holds at 750 ohms. When I checked it by manually moving the coils the ohm reading wasn't stable and going out of spec. After re-checking the coil wires I discovered the blue wire going to the same coil also has a break in it. I'll probably get to that one later tonight or tomorrow.
On the bright side after applying oil to the bearing two days ago it no longer sticks and will return every time. Aren't these old bikes fun?..lol

[DavePlum]

I came to the conclusion it will much easier to repair the pickup coil wire if the timing plate is removed as there's just not enough room to get my crimping tool in there and see where I'm crimping it at. A couple of questions: Is it as straight forward as just removing the allen head bolt and pulling the plate off? Do I need to put a wrench on the end to use as a backup wrench while turning on the allen bolt to prevent the crank from rotating? Do I need to be concerned where the timing plate is aligned with the pointer before removal or is the timing plate have a notch or something that only allows you to install it at the correct orientation to the pointer? Anything else I should be forewarned about if I go this route? Thanks

[bikerphil]

I put the reluctor tab at about 10 o'clock to line up with the slot in the plate so the unit can slide off to be repaired. Take off the Allen bolt and the two that hold the unit.

[motoman]

Thanks for all the responses and suggestions. Thanks for the heads up on the difference between the 79 & 80 timing curve. Even if it was doable I wasn't looking forward to swapping the entire assembly out.
Using the (pull wire look for stretching method) I found exactly where the break was. Once I had cut back the insulation I held the bare ends together and my meter read 750 ohms at the TCI connector. Turns out it was the white wire.
I also applied some oil to that bearing and it already turns much easier but still does not return if I turn it all the way. Anyone know how many degrees it normally moves? Before I applied the oil it would only move a few degrees would be a bit squeaky and stick, it now the squeak is gone and it moves about twice as far before it sticks. It only fails to return when I move it full travel, if I go 90% of full travel and it will return fine. Hopefully it will begin to consistently return after full travel as the oil soaks that bearing.
I also went ahead and checked ignition coils (primary and secondary both within specs), I also checked the emergency kill switch and it checks out fine as well.
Hopefully I can get that wire fixed tomorrow using wire leads from a DVM and give an update. btw...I have a talent for breaking off DVM leads so I have plenty of wire.

Yes......the white wire, apparently from its movement and rotation seems to be the common one that wires break internally. Good find.