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How Do I Time This Thing?

Posted: Thu Aug 27, 2015 9:14 pm
by Nailhead
I'm entering late middle age, but I'm young enough to have JUST missed the points-&-condenser ignition era. I think the last time I messed with points ignition was on an Alfa or Fiat 600 sometime in the '80's, and I can't remember how to static time an engine after removal of the distributor (bean can).

The points have been set to a Clymer-specified .040, and the BC is reinstalled at the approximate angle it was when I removed it (according to an iPhone photo...).

What now?

I feel like a moron.

Re: How Do I Time This Thing?

Posted: Thu Aug 27, 2015 9:58 pm
by SteveD
What's late middle age? I've gotta get that out of the way before I can put my mind to a motorcycle question! I wondering if I should be considering it too? ;)

There's a small tool that helps a bit.
Image

Duane. http://www.w6rec.com/duane/bmw/points/index.htm

Snowbum. http://bmwmotorcycletech.info/ignitionsingleplug.htm

Chris Harris.https://www.youtube.com/watch?v=HShbaC9ORSo

Re: How Do I Time This Thing?

Posted: Thu Aug 27, 2015 11:07 pm
by Major Softie
"Late Middle-Age" missed points and condensor? DAMN, I'm ancient!

Re: How Do I Time This Thing?

Posted: Fri Aug 28, 2015 4:44 am
by chasbmw
Always use a Dooby paper to check when points are opening, smoke it afterwards!

Re: How Do I Time This Thing?

Posted: Fri Aug 28, 2015 5:34 am
by pat76r90
ZigZag or Tops? They're different thicknesses.

Re: How Do I Time This Thing?

Posted: Fri Aug 28, 2015 7:15 am
by barryh
If you set the points gap with the bean can removed that was a smart move as it's much easier.
If you set the gap with the outrigger bearing plate removed you'll find the gap changes when you put it back on.
Points gap is .4 to .5mm or 16 to 20 thou. It's not hyper critical but you do have to get the decimal point in the right place. I'm too old for this metric nonsense and it confuses me so I work with thous.

With the can back on the bike, plugs out, rotate the engine slowly with an Allen key in the rotor bolt until you see the S mark in the timing window just opposite the chiseled timing mark on the side of the window. With this alignment the points should just be opening which you can check with what ever method is preferred - fag paper, test light or my preference a buzzer so I can hear the buzzer go off while concentrating on looking at the timing marks.
In the pic you can just about see that my chisel mark is a little below half way down the window so that's why the S mark is also a little below. The actual timing mark on the flywheel is not the S but the adjacent dot or drilling that I've filled with white paint. You can also just about see the TDC make which is the Line at the top of the window. Above that is stamped OT. When doing static timing you are rotating the flywheel towards you so full advance comes into the window first followed by the S and then OT. The exact look of timing marks varies between models so yours might not be exactly the same as in the pic.

It's a good idea to then check full advance with a strobe light but mine is always spot on so I routinely only bother with the static timing.

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Re: How Do I Time This Thing?

Posted: Sat Aug 29, 2015 10:46 am
by Nailhead
Thank you very much!

I think I gapped those points with the bearing carrier on, but I'm going to double check it.

Re: How Do I Time This Thing?

Posted: Thu Sep 03, 2015 1:44 am
by Nailhead
Points regapped (they were way too loose, so I must have gapped them with the bearing carrier off), static timed per instructions using the beep on my Fluke meter. I didn't have the key handy, so I wasn't able to start it & check running.

I just have to scare up a timing light (haven't seen one for years), start It, and we'll see how it goes.

Re: How Do I Time This Thing?

Posted: Thu Sep 03, 2015 1:28 pm
by barryh
Unless the advance mechanism is worn there is no reason to believe the timing will necessarily be wildly out at full advance so I'd be happy to ride it until you can check with a timing light. Just listen out for any pinging as the engine approaches 3000 RPM under load.

Re: How Do I Time This Thing?

Posted: Thu Sep 03, 2015 8:31 pm
by Nailhead
Thanks Barry.

One thing I noticed that's troubling me is the position of the bean can now: it's at the limit of its CCW adjustment travel, whereas when I pulled it initially it was at 3/4 CW travel, and the bike seemed to run fine.

I would like to complete the timing process at this point because it's a PITA to remove the lowers on this bike. About a fistful of little Philips screws.

I just might take your advice, though-- it would justify running without the lowers for a while. I never thought it would look good as it does without them.