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Discussion Starter #1
I bought a 81 Pantah 500 for 500 bucks at an estate sale. The bike is complete but had been parked in a not very weather tight shed since 1991...12,000 kilometers shown on the speedo The engine turned over .... . My wife and I cleaned it up. Checked the timing belts and cam timing, checked valve clearances .All was ok so changed the oil and filer. Put in fresh gas and it startedd after a bit of cranking. The carbs need cleaning so it needed the chokes on to run at low speeds. But with chokes off it reved smoothly...Ran it for 10 minutes, then it stalled and would not restart despite seeming to have spark and fuel...Cam timing was still good so I worked on cleaning years of corrosion from the wire connections
Well it still won't start ,backfires a bit from the mufflers and occasional flames. Checking the ignition wiring, the insulation is cracking off on the ignition pick up leads..Pulled the left cover and the pick ups and wire looks pretty bad but the pick leads still measure 220 ohms each...
So it sure sounds like ignition issues and obviously the pick ups need replacing. I would hate to spend 200 bucks on pick ups and it still might not run..The bike came with a Ducati service manual but it doesn't state how to check the control boxes. The coils and resistors check ok using an ohm meter...
What do you think? Replace the pick ups? Thanks
 

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I don't know about the ignition, but first it might be a good idea to get the carbs ultrasonically cleaned, as there will be all sorts of gum clogging them up. Secondly, check for air leaks in the manifold junctions, these are sealed at the joint with 'o' rings, which may have rotted and be letting in air; and thirdly, please do not run it for any length of time without replacing the timing belts, they were not particularly strong back in the day and after standing for twelve years could break easily!

It is a common procedure to replace the pick-up wires, soldering new ones into the pick-ups, so that might be all you need. Hopefully Craig on this site might enlighten you more. Good luck.
 

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Discussion Starter #3
Thanks, the carbs were actually clean inside, it appeared the bowls were drained before it was stored...I did check the manifold o rings . The compression cold after sitting for a week is 125 on both cylinders...
It did start up several times before this so hopefully it's the PU wiring....
 

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You can, if you are careful, replace the wires. Bevel Heaven sells a kit with oil/heat resistant wire. Basically you cut and splice wires onto the leads coming out of the pickups.
 

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As per Colin and Bill, really ...

As the insulation falls off the original wiring, you can get rogue signals being generated that make the ignition boxes spark all over the place - hence your back-firing and flames.

The good news is that your resistance value for the pick-ups themselves (220 Ohms) is right on the money. So they should be ok and shouldn't need replacing.

P.s. As per Colin. Definitely, BUT definitely, change the belts. This really is a case of, "No Ifs, Buts or Maybes".

P.p.s. $500 for a Pantah! My, you did well!
 

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Discussion Starter #6
Thanks guys...for 32 bucks I got high temperature oil resistent wire and actual oil and temperature resistant shrink tubing from McMaster Carr online. The original wires are not removable from the pick ups but left cleaned stubs for soldier...My first ohm readings were using a Fluke digital...readings were inconsistent..Got out the old Simpson analog meter an both rang out a steady 200- 220 ohms. I did mark the wires as they were marked. Are the pick ups polarity sensitive
 

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<snip> Are the pick ups polarity sensitive?
Yes. Here are some instructions from 'Someone Who Knows' on how to check/re-set:

"When all is installed, stick some plugs in your plug caps, ground them, power up the ignition and get a thin-bladed screwdriver.

With the ignition turned on, place the screwdriver blade across the magnetic poles of one pick-up and pull it off sharply. You should see a spark at the corresponding plug.

If you see a spark as you APPROACH the pick-up, the polarity is incorrect. In this case, simply swap over pick-up connections. Repeat for other pick-up".

HTH

Craig
 

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Discussion Starter #9
Rick, I do have the factory manual, thanks.....I got the pick up rewired, tested and mounted. Set the pu to flywheel gap......this may sound dumb because I thew out the shabby original wire, looking at the two pick ups, which one is the front horizontal cylinder...?
 

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Discussion Starter #10
Duh...to answer my own question just rotate the engine ,watch through the plug hole to see the intake valve open and close and when the piston comes on compression look to see which pick up is ready to trigger the ignition...
 
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