Mag points open unevenly

[CheeserBeezer]

On my shelf of disasters is a cam ring which came from a mag I bought. Timed up one side to 32 btdc and checked the other which was 57 btdc.
I was but a spotty youth when I bought this and made the elementary mistake of only setting up the timing on one side. The result was a holed piston and a con rod which let go at the small end.
Freckenham Red Lodge is an oddly named place to be stranded in the pre-mobile phone pre-recovery era and was only 200 miles from home...
Ever since then I have been very careful to check the timing on both cylinders.

....almost certainly from a V-twin

[CheeserBeezer]

Which ones? Don't tar us all with the same brush, please?!

Many isn’t all.

I know, but 'many' cast suspicion on all.

[groily]

Freckenham Red Lodge is an oddly named place to be stranded in the pre-mobile phone pre-recovery era and was only 200 miles from home...
Ever since then I have been very careful to check the timing on both cylinders.

Was a very good 24hr caff though BS, with an excellent juke box back in the day - I'm talking 50 years back. But still there the last time I passed that way. Oddly named, yup - just down the road from Six Mile Bottom  . . . where I came to an involuntary halt one time with a holed crankcase on an A10. Not so great at 2 in the morning  . . . . .

[limeyrob]

So is the conclusion that this is caused by an eccentric end cover or inaccurately machined cam ring?  I've never seen any significant wear in either so what they are now is how they were made?

[groily]

Too early for conclusions Rob - could be a number of things. But camrings wear and 'things' happen to housings, including the consequences of mix and match. But a few other areas to look at too depending on what the refurbisher did or didn't do. Have to wait to hear back I think.
Inaccurate firing intervals and unequal points gaps are just extremely common on K2Fs, especially - but far from only - on those with manual advance. (Not the case here though, I'm guessing.)
It can take longer to sort out these sorts of issues than it takes to do almost anything else on these mags. I always let out an inward cheer if a reassembled one comes in at under 1° of error on the mag across the speed range on test, and a loud groan when the thing is miles out and is going to be a time-consuming bore.
For reasons of their detail design, I've almost never come across the same issues with KC2 BTHs, or indeed with Bosch twins.