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Ignition (and other) questions

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wbmoore
Posts: 81
Joined: Sun Nov 16, 2008 7:26 pm
Location: Big Bar, Ca.

Ignition (and other) questions

Post by wbmoore »

Just had the engine rebuilt for my 1960 R69. Was thinking I would get a nicely running bike back but I guess there was a communication breakdown between myself and the builder. Now it’s up to me to make it so.

I’m assuming the engine is fine so it must be Carburetors and Ignition that are the current problems. When I got it back it would not idle. Fixed that: cleaned idle jets. Runs rough and will not build RPMs. Somewhat have fixed that: cleaned Air Regulating Screw.

Moving on to Ignition. The Retard/Advance gag has been removed by me with a Vech kit (if memory serves...ten years-no miles ago). After the bike came back from the rebuilder, the first thing I checked upon discovering a very poorly running bike was the ignition. After reading Vech, SNAFU and Ausherman I checked the “S-mark” on the flywheel and the “V notch with the line” on the Brass plate. When the line is centered in the V, the S-mark is just out of the viewing window when viewed straight on. It is just above the viewing circle.

Is that to advance or retard the ignition (and done on purpose)?..........or is that just Wrong ?

The builder is a very experienced BMW mechanic.

I know what you’re thinkin’....why don’t you just call him ??? Life is full of changes and he has moved on to a new life, far, far away.

The plan is to make it run better, if possible, as is. I’ll swap out the points/condenser. Then go through the Carburetors. Don’t really want to swap to 12V/electronic ignition as I’ve just bought a new 6V battery and box but if that’s what will fix it then that’s what will be done.

Thoughts from people in the know please. Thanks. Brad Moore.
Brad Moore
1960 R69; 1975 Norton MKIII; 1976 R90/6; 1992 K75S; 2000 Hayabusa
Big Bar, Northern California

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Micha
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Re: Ignition (and other) questions

Post by Micha »

Hi Brad,
Because of the time differences, it is noon now so I'm just the first to answer.
If you look at my previous threads here, not long ago, you will understand that my situation was also unclear on these issues. In my opinion, first thing - valve clearence check and this v notch on the brass plate.
After these - see if there is any improvement.
I'm sure smarter and more experienced than me will come in here later and donate their wisdom, but I would start at the base.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

Daves79x
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Re: Ignition (and other) questions

Post by Daves79x »

As Michael said, setting the mag timing is most important. Requires removal of the mag rotor. Make sure all the mating surfaces of the mag body are clean and tight, for a good ground. Make sure you have a new or newer ignition coil. I'd at least put in a new condenser and clean the points. Set static timing to the S mark, starting with the specified points gap. If the movement of the backing plate (NOT the mag frame) won't allow correct timing, then alter the points gap. A little goes a long way. You must have your static timing set correctly and hopefully not too much differential timing (same mark when checking both cylinders).

As mentioned, be sure your valve clearances are correct and they are measured on the compression stroke on each side.

Then you should completely disassemble the carbs, carefully chase all threads, especially the mixture screw ones, soak the bodies and blow out all passages. Base set your mixture screws (two turns out for the R69, I think). Set each idle screw so the slide is JUST lifting. Then adjust the throttle cables so both slides are picking up at the same time. This will get you close, to get it started.

It should run fine at this point, but the timing needs to be verified with a timing light, both idle and full advance, and the carbs' mixture screw need fine tuned. Take an old spark plug and install it into one plug wire, then using a clip jumper, ground the plug to the head. Start the bike on the other cylinder and get it to idle. Turn the air screw out (leaner) until the revs drop, then turn in inward until the revs drop. Then find the sweet spot in between, usually the fastest idle. Then maybe in (richer) an eighth of a turn. Then do the other cylinder the same way. Then set your idle sync and just-open throttle sync pretty quickly too. Empi-gauges are the best for that to most un-trained ears (mine included).

After all that you should have a pretty well-running bike.

Dave
Dave

wbmoore
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Location: Big Bar, Ca.

Re: Ignition (and other) questions

Post by wbmoore »

First things first: Michael, hope you and yours are safe.

Michael, Dave,
I’m assuming (I know, I know) that the valves are adjusted correctly . The guy that built the engine is a longtime BMW motorcycle mechanic. With that said please see the drawing below.
F6E91A6C-B3B5-43AB-AA0A-3FFD50B2ECB5.jpeg
Is my current setting acceptable ? Or should I adjust it to resemble the lower portion of the drawing ? Could the current setting be an attempt to modify timing “for performance” or is it simply an assembly mistake ?

Sometimes it will start and run (never smoothly) with a few kicks, other times it just won’t start. I don’t like to make more than one adjustment without running it.

Thanks for the input.
Brad Moore
1960 R69; 1975 Norton MKIII; 1976 R90/6; 1992 K75S; 2000 Hayabusa
Big Bar, Northern California

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Re: Ignition (and other) questions

Post by schrader7032 »

You should adjust to get the lower image. As it is, you're firing the plugs before the S-mark which is advanced.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

Daves79x
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Re: Ignition (and other) questions

Post by Daves79x »

Re-read what I said first. Yes, the 'S' has to be at least in the window. I described how to get it there. No shortcuts. No shortcuts with the carbs either, they have to be cleaned as I described. If you don't do this step-by-step, you will always be chasing something. Forget trying to start it until you get all the above taken care of.

Dave
Dave

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