Whar's the S?

[Primate]

Oops, pardon me-- 1st post by new guy--just another Airhead kook here. Howdy.

Having misfiring issues on Thor, my hardy '74 R90/6 I bought about a year ago. Following the advice of an extremely knowledgeable and helpful Airhead, I replaced the points & condensor. First time doing it--followed the advice in Clymer and used the points tool and all, but now I can't get it to fire up. Using a static timing device, I hoped to narrow down the possibilities, BUT . . . for the life of me, I can't find the S on the flywheel. The OT and F are there, but no S.

The flywheel is used. But back to my question-- here's what I've found in my amateurish sleuthing: Looking at the alternator rotor, and imagining a clock as a reference, and OT is 12 o'clock. Turning the rotor clockwise, the F is all the way around at about 10:30 or 11. Where should the S be? Be ause right now, the static timer light comes on at about 3, and judging by the startup, getting nothing except maybe a spark or two every 15-20 seconds. I have to be way off.

There's the background. Now my questions:

Where should I find the S using the clock layout?

Is it possible other models/years didn't use the S?

What do S and F stand for?

Thanks all,
Primate of the great and mighty Inland Empire of Southern California.

[ME 109]

Welcome primate, your questions will be answered soon.
But from my limited knowledge, different bm's have different lettering on the flywheel.

Mine has OT, and a Z close by. I use the Z to time.

If you cant find 'S' it is possible that the flywheel has been put back on incorrectly. The flywheel can be put on 5 different positions.
You can check correct position by getting a cylinder to top dead centre on compression and seeing if OT is in the window.

[Primate]

Thanks ME, yes, I'm at TDC on compression with OT in the window.

[ME 109]

Thanks ME, yes, I'm at TDC on compression with OT in the window.

Well the flywheel is on correctly. And as for compression, well that doesn't matter for this test does it

[ME 109]

Had a look at my cluch carrier............ Z is nine teeth before OT

[chasbmw]

On your 74 90/6 the standard flywheel should have 92 teeth. That gives you 3.9 degrees per tooth.

The S or Z mark should be approx 6 degrees before OT (TDC). You time on the DOT, or on the middle of the 3 lines . S is at 11.50 ish, just before TDC

Ignition timing at full advance is more important that getting it correct to the last degree at static.

(worth counting the flywheel teeth, as you don't know what modifications have been made) possibly the S marked was removed when the flywheel was lightened

For ease of adjustment fit an electronic ignition

[George Ryals]

You said you can't get it to fire up. Is it trying to start?? But won't continue to run ? Or you getting nothing, like maybe the points wire is pinched under the cover or something has the points grounded?

[Primate]

Thanks Chas--I actually found the S the night before I saw your advice, but counted all 92 teeth just to be sure. If that was an initiation rite for this forum, then there you are--well done. But the S looked nothing like the OT and F lettering--it was much smaller and tipped on its side. That's why it eluded me for so long.

George--funny you mentiuon the points wire being pinched under the cover because that actually did happen before I came to this forum. I electrical taped it up and pulled the white sleeve over it, which I'd neglected to do in the beginning. But even with that out of the way, still no starting. What I mean by that is the engine turns over but won't fire up. I am getting sparks on both sides, though. I'm not sure if the Bing carbs can flood or not, so I emptied them and let them refill--still nothing.

I may be getting some more help, this or next weekend, not sure. I'll keep working my noggin until then.

I really appreciate all the help you are are giving, but right now, it's dinner time, and there's pasta and beer waiting downstaire.

Thanks again all,
Primate

[ME 109]

A big bright blue spark is what you want.

[KPWest]

I noticed your in the the IE, in case you don't get an answer for your problems, there is a Tech Day in Murrieta on May 4th. That five or so weeks is quite a while, but you're going to have a lot of experienced guys there, and I guarantee they would love a project.

Whether or not you get it sorted out, you should come by. Let me know if you need the guy's address.