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Discussion Starter · #1 ·
There are plenty of you that have had trouble getting a Lucas to work right:D, but have any of you had one that would not QUITE:mad:?
I have a Lucas K2FC mac that can not be shut off. It is freshly and completely built/remgnetized, new armature w/modern condensor by Beno Rodi (very reputable racer, Brit expert, and has also never heard of this problem). This mag functioned perfectly from the start. I used a switch from the cap (same as many times before) to ground to shut it off, which worked fine for the first few dozen miles. I have had the cap off, while running, and put a wrench from the center contact on points plate to the primary (it does show sparks, so is getting contact) as well at the motor case, while this should kill it, it continues to run. This test takes the cap and cap-brush out of the equation. I have removed the center stud, wire brushed the whole thing including threads spotless as well as the head that the cap brush contacts, and cranked it all back together...it still runs. Beno says if this center stud had any continuity issues from the armature to the points plate, the mag would not fire.
Since elctrons take the course of least resistance, I wonder if opening the plug gap a bit may make the path though the brush, cap, wire and switch that easier path? But I have never had adjust the plug gap on any other rebuilt Lucas mag bike to get it to shut off. I am sure there is some underlying issue that I am missing.
Have any of you guys had a Lucas K2FC that refused to die?
Thanks, Dan.
 

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You may have to drop the clutch when ya parking.
Ordinary house hold light switches can build up copper oxide and be a total open circuit , simple contact clean/scrape/file an theyre good to go.

Could be open somewhere in there and cant earth . I stuff around with HV and I know once you go for more spark gap you can increase internal arcing thats why pretty much all coils are encapsulated to the max.
It might be theres a insulation break and its behaving like a tapped coil while your trying to short the 'dead end' .

Thered still show continuity in the full length of coil . Theres a Megohmeter or Megger that tests circuits with a wallop , thatll show any break down of insulation. Minus cap and points ,+ removed from bike, its a shit load Voltage.
 

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Just keep adding Gas!!! Keep it running while you can!!! :rolleyes:

No realy, some thing is not making contack to stop it, the switch is a ground, so relook at the mag, it is in there some where, just dont let out the majick smoke!!!:eek:

.........Roach.
 

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there is a little round carbon contact under a slotted screw near the Lucas label, unscrew that and stretch the spring a little then shoot some carb cleaner in there to clean off any oil that got past the seal. Put it all back together and it should be fixed.
 

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Discussion Starter · #6 ·
Tony,
Thank you, thank you, thank you! You are the man! That was exactly it. I guess next time I get a mag fully rebuilt, I'll replace all the brushes myself, after the fact :D
Cheers, Dan.
 
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