How rare is this?? New old stock K2FC Magneto

Bernhard said:
Notwithstanding the question mark of the life of the capacitor, please check that it fires with a degree disc, whether on the engine or not, that it fires at 0 and 180 degrees exactly.
If it is out more than a couple of degrees, it can be corrected .
Click to expand...

This condition (firing other than 0 & 180 degrees) is almost always related to the cam ring producing unequal point gap on each ramp.

First step in setting up a K2F should be to check the gap on each ramp. I have measured a 2 degree difference in firing for each 0.001 inch difference in gap. I have also experienced 10 to 12 thou differences in gap on my own, and the mags of others, which can result in over 20 degrees difference in firing.

Cam rings were notoriously mis-machined, because of old, tired, worn out machinery following WW2. Sometimes, these cam rings produced equal gaps, but the cam ramps were not 180 degrees apart.....the only way to correct such rings was to stone down the lead ramp, a procedure not recommended by modern standards. Newly CNC made cam rings are spot on, but unequal gaps occur if the ring is not perfectly centered in the housing.

Slick
 
texasSlick said:
Bernhard said:
Notwithstanding the question mark of the life of the capacitor, please check that it fires with a degree disc, whether on the engine or not, that it fires at 0 and 180 degrees exactly.
If it is out more than a couple of degrees, it can be corrected .
Click to expand...

This condition (firing other than 0 & 180 degrees) is almost always related to the cam ring producing unequal point gap on each ramp.

First step in setting up a K2F should be to check the gap on each ramp. I have measured a 2 degree difference in firing for each 0.001 inch difference in gap. I have also experienced 10 to 12 thou differences in gap on my own, and the mags of others, which can result in over 20 degrees difference in firing.

Cam rings were notoriously mis-machined, because of old, tired, worn out machinery following WW2. Sometimes, these cam rings produced equal gaps, but the cam ramps were not 180 degrees apart.....the only way to correct such rings was to stone down the lead ramp, a procedure not recommended by modern standards. Newly CNC made cam rings are spot on, but unequal gaps occur if the ring is not perfectly centered in the housing.

Slick
Click to expand...

Just curious guys. This magnetos box is date stamped January 1971. In 1971 did Lucas still have shitty machining and crappy capacitors/condensers or did they make improvements? Or was it made 20 years earlier and then put in a box at the Lucas factory in '71? Also, this magneto had a letter stamped on it after the model number....72368 D. Anyone know what the "D" represents?
 
JohnnyMac wrote:

"Just curious guys. This magnetos box is date stamped January 1971. In 1971 did Lucas still have shitty machining and crappy capacitors/condensers or did they make improvements? Or was it made 20 years earlier and then put in a box at the Lucas factory in '71? Also, this magneto had a letter stamped on it after the model number....72368 D. Anyone know what the "D" represents?"

The capacitors are not necessarily crappy....they were made of paper rolled up with aluminum powder between. With age, 30 - 40 years, the paper simply deteriorates and the cap shorts out. Modern replacement caps will probably be made of polystyrene, and have an indefinite life.

As far as the machinery....and it's age when put in the box. Who knows?

My K2FC has the suffix D. I haven't a clue to its meaning. I am not with the bike right now, but I can report my serial number later. Perhaps that can give a clue to date of mfg of your mag.

In any event, you stated it was your intention to send the mag out for a new cap. Tell the rebuilder to do a firing angle check on the cam ring as well. This should be part of a routine rebuild, but the guy might be tempted to skip it because the mag is "new".

Slick
 
It's likely that your "new" mag was finished, checked, wrapped and packed in 1971. The job card would have been completed, and the last operation would be something like " ...wrap in brown paper, put in box" then final destination "Store"
cheers
wakeup
 
The mag has a date stamp right on the tag, which will tell you the exact month and year it was manufactured.
Looks like it says 4/71 on it. It's the middle set of numbers. Can't quite read it off the photo.
That's actually pretty late in the production of the Lucas K2FC. I'd use it as is. Likely it's perfect. If it needs a rebuild, it'd likely just be the capacitor.
 
Well we disassembled it this afternoon. Apart from the bearing grease (which was very crusty) it looks brand new inside. Oil seal is fine too. We isolated the condenser/capacitor and are going to install a BrightSpark easy cap. That way if there are any future condenser problems, it is an easy fix.
 
Well, I got it rebuilt and added the BrightSpark Easy Cap Condenser. This think has got one heck of a spark! I can't wait to get it on the bike.

How rare is this?? New old stock K2FC Magneto
 
The advice to replace the cap was good as these caps have a finite life but if you have not remagnetised the magneto as by removing the armature the magnets have lost 30% of their strength it may not fire inside an engine. So if you find it not firing when installed this would be the first area to look at.

http://www.britbike.com/forums/ubbthrea ... Post446733

A few final comments about the magnets: An often repeated piece of advice when restoring magnetos is to immediately place a steel "keeper" across the poles of the magnet as soon as the armature is removed to keep the magnet from losing its strength. Unfortunately, this advice is wrong. No matter how fast you are, a keeper will do you no good at all because the magnetic domains rearrange themselves nearly instantaneously (less than a millisecond). However, enough strength will be left that the magneto will still spark across a spark plug at atmospheric pressure, so you might think things are fine. They are not. A few other wrong, but harmless, pieces of advice you might run across for achieving full magnetization include charging the magneto 4-5 times (once is enough), holding the electromagnet at full field for a number of seconds (a fraction of a second is plenty), and tapping the magneto with a brass hammer while the field is applied (harmless, but pointless).
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As it looked to have been a brand new NOS magneto I would have followed TT's advice and fitted it and if it failed got the cap changed then by someone who could remagnetise it.
 
I am not an expert, but I don't understand how removing the armature on an unused magneto could result in the loss of 20% of its magnetism. That sound highly unlikely.
 
Johnnymac said:
I am not an expert, but I don't understand how removing the armature on an unused magneto could result in the loss of 20% of its magnetism. That sound highly unlikely.
Click to expand...

It's what they say.
 
All the manuals describe how to fit a 'keeper' when the armature is removed,
so as to retain the magnetism....
 
Johnnymac said:
I am not an expert, but I don't understand how removing the armature on an unused magneto could result in the loss of 20% of its magnetism. That sound highly unlikely.
Click to expand...

I have read of magnetic strength loss in some tech bulletin regarding the K2F somewhere. You should research this issue before mounting on the bike.

Slick
 
chris c said:
K2F mag is self keepering and will only lose about 3% of its magnetism when disassembled Have a look at Brightesparks website.
http://www.brightsparkmagnetos.com/faqs ... agneto.htm
Click to expand...

Thanks Chris. I'm not worried about it. I spoke to Doug Wood and had it worked on by a very reputable guy here locally who has worked on hundreds of mags.... It's a fantastic magneto and I couldn't be happier! I will certainly post pics and results when I finally get time to work on my bikes. :)
 
Johnnymac said:
madass140 said:
yep pretty much guaranteed, you will get 30 miles down the road and then it dies,
Click to expand...

I guess I will put a new condenser in it before I even put it on he bike. Thanks guys.
Click to expand...

The condenser is inside the armature and DON'T use a NOS Lucas condenser.
John in Texas
 
Johnny boy... please hurry up and fit this damned magneto of yours. We need to know who wins here... the 'optimists' who say "just fit it" or the doom mongers who say the world will implode if you do.

Come on man... do the deed...
 
Fast Eddie said:
Johnny boy... please hurry up and fit this damned magneto of yours. We need to know who wins here... the 'optimists' who say "just fit it" or the doom mongers who say the world will implode if you do.

Come on man... do the deed...
Click to expand...


Haha, thanks Eddie. Unfortunately the ass clown who is making my oil tank is awol again and since I sold my old one, I am in a holding pattern. It sucks.
 
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