No spark on either plug

[jschara]

When I bought back my 1979 R65 a few years ago it was running rough. It had been neglected but not abused. It's been laid up for two years so that I could pick away at it and spruce it up. New clutch, rebuilt the carbs, complete fluid change, new battery and battery cables along with valve adjustment.

Started on the first try but was running very rough and would not idle. I checked and there was a very weak white spark. Changed the points and condenser and now I have no spark. Installed new spark plugs and spark plug wires.

I check the ignition coils per Matthew's Parkhouse's article (Secondary Ignition Systems Checks, in BMW Owners News, June 2002) and got a reading of 23.1 k-ohms between the spark plug caps. Also checked the coils from the plug opening to one of the spade connectors to get a reading of 6.31 k-ohms on the right coil and 6.45 on the left coil. All the connectors from the alternator and connectors to the coils have been cleaned.

Should the voltage regulator be the next check, and how would I do that?

Advice greatly appreciated,

Jim

 

[pglaves]

When I bought back my 1979 R65 a few years ago it was running rough. It had been neglected but not abused. It's been laid up for two years so that I could pick away at it and spruce it up. New clutch, rebuilt the carbs, complete fluid change, new battery and battery cables along with valve adjustment.

Started on the first try but was running very rough and would not idle. I checked and there was a very weak white spark. Changed the points and condenser and now I have no spark. Installed new spark plugs and spark plug wires.

I check the ignition coils per Matthew's Parkhouse's article (Secondary Ignition Systems Checks, in BMW Owners News, June 2002) and got a reading of 23.1 k-ohms between the spark plug caps. Also checked the coils from the plug opening to one of the spade connectors to get a reading of 6.31 k-ohms on the right coil and 6.45 on the left coil. All the connectors from the alternator and connectors to the coils have been cleaned.

Should the voltage regulator be the next check, and how would I do that?

Advice greatly appreciated,

Jim

Assuming the battery cranks the engine there is no reason to suspect the voltage regulator. It applies to charge the battery and has nothing to do with ignition spark.

I suspect your problem is with the points.

 

[20774]

I think Paul is on it. With the change of points, you've likely messed up the gap and either the gap is never opening or it is never closing. Go back and check points gap...should be around 0.016" (or 0.4mm), then recheck the static timing. The gap can vary a bit, so don't get hung up on that. We just had a thread about setting the timing on a '77 R100RS.

 

[stevenrankin]

China points

Just for my own knowledge, are the cheap bad points mentioned a few years ago still floating around? I don't remember the whole story just they were from China, cheap and from what I remember could not be adjusted correctly. Would someone be unfortunate to still get a set by accident today?

Not that my question has anything to do with the problem. Paul and Kurt have it nailed down.

Frankly, I got rid of points on my 78 and have been living happily ever after. Cheers St.

 

[Omega Man]

If a battery is on the weak side, sometimes the cranking takes almost all the power not leaving much voltage for spark. I would look at voltage drop “while cranking”.
OM

 

[20774]

Chinese point discussed here:

https://forums.bmwmoa.org/showthread.php?68332-Timing-and-points-problem-1976-R90-6-not-starting

Matt Parkhouse covered "counterfeit" points in the September 2010 ON.

 

[jschara]

Yep, you guys were right. Points. Pulled the bean can and put a second set of points in and that did the trick. The set I tried first were old stock BMW and I guess they were defective. Second works fine.

Thanks for the help,

Jim

 

[stevenrankin]

Good news

Good news for you! Thanks for letting us know what you did. St.