Magneto End Plate / Cam Housing Issues

Recently looked down at the rebuilt K2f on my Atlas while it was running and noticed that the end plate / points / cam housing was loose and bouncing around. Worth checking for this before looking for other reasons why the points are not breaking evenly on the two cam ring ramps. I guess there's a reason why the two cheese headed screws (some would call these bolts) that hold the end plate are often pre drilled for safety wire. I suspect this was not a problem with new magnetos from the factory but worth checking with even the best rebuilt magneto.

This could affect the spindle/armature shaft alignment (parallelism). Out of parallel alignment can throw off the point gap on the two ramps of the cam ring, and also cause binding in the magneto chain drive.

I would remove the magneto from the bike and either DIY dial in the shaft, or send it out to a competant rebuilder.

Slick

This happened on mine. I put Loctite on the screws and had no more trouble.

texasSlick said:

This could affect the spindle/armature shaft alignment (parallelism). Out of parallel alignment can throw off the point gap on the two ramps of the cam ring, and also cause binding in the magneto chain drive.

I would remove the magneto from the bike and either DIY dial in the shaft, or send it out to a competant rebuilder.

Slick

Click to expand...

This is a very important point.

Check the ignition timing on both cylinders!!! ie on both lobes of the cam. If the shaft is out of alignment then you may (or will) have different ignition timing on each cylinder. If the difference is one or 2 degrees you can split the difference. If it is more you MUST correct it otherwise you will seize it or get pre ignition. I can tell you this from personal experience.

I can confirm that if your ignition timing is out by as much as 7 degrees on one cylinder while the other is correct, you will eventually chew up a piston.

For loose cam ring, clean with paint thinners, put some Loctite bearing lock compound on outer cam ring before inserting it. Check timing on both cylinders before riding.

https://www.amazon.co.uk/Loctite-St...id=1536929236&sr=8-2&keywords=bearing+loctite

Not sure why you would put Loctite bearing lock compound on the cam ring. The ring is fixed in place by a slot on the ring and locating peg on the body of magneto end plate housing so it cannot rotate out of position. As far as securing the ring from coming out - based on how hard it is to remove or replace, it is a pretty secure interference fit. FWIW I ran the bike about a hundred miles today and it ran fine other than firing a bit more evenly at idle on one cylinder than on the other. I will take the magneto off this winter and blue print the cam ring / point gap - although sometimes my efforts only go to prove that the enemy of good is better.

Bodger said:

Not sure why you would put Loctite bearing lock compound on the cam ring.

Click to expand...

I agree!
TexasSlick posted some very good information on correcting cam rings that were not concentric with the magneto shaft.
Can't find it just now but I'm sure he will chime in and help.
Very good information that helped me.
Cheers
Rob

robs ss said:

I agree!
TexasSlick posted some very good information on correcting cam rings that were not concentric with the magneto shaft.
Can't find it just now but I'm sure he will chime in and help.
Very good information that helped me.
Cheers
Rob

Click to expand...

Here you go! https://www.accessnorton.com/NortonCommando/setting-up-and-timing-a-k2f-magneto.19685/

+2 re: Loctite on the cam ring. Perhaps put blue loctite on the grub screw, but other than rotating out of position, it cannot go anywhere. Sometimes those cam rings can be hard to remove .... no sense in making it harder.

@Robs as
IIRC, you can attest that my K2F timing setup cannot correct an out of parallel spindle. The OP must ensure the spindle or armature shaft is parallel aligned before setting up the point gaps.

Slick

texasSlick said:

@Robs as
IIRC, you can attest that my K2F timing setup cannot correct an out of parallel spindle.

Click to expand...

Yep - I had a poorly assembled armature/shaft assy so it wasn't straight - now corrected, but...
Your advice allowed me to make the points gaps equal on both sides of the ring!

Rob