Ignition Problems

[bigdaddy]

Hello,

I noticed some unusual thing today, my R75/6 run ruff, now the test on other gas motors that I use to find any working or not working head is to pull the spark plug wire, if no change is noticed, the cylinder is not working right, right?

Now, I pulled the left cable and the bike quit, when I pulled the right I noticed that the bike run nice and round when I held the spark wire connector about 1/2" away from the spark plug.

Any idea what this good be or mean? The connector making contact looks fine.

All the best,

Joerg K.

[Bullzaye]

bigdaddy,
Hi. I'm afraid that I'm not really much of a mechanic, so I won't be much help. Are you saying that as your moving the sparkplug wire, the engine is running more smoothly? Perhaps you have a short in that wire, or the wire is only contacting by a few threads, and when you move the wire, the connection is improved. In that case, I would think that a new sparkplug wire should fix you up.

If that's not the case...I'd say you might want to repost your question in the Motorcycle Repair forum. The problem sounds generic enough that some may have helpful ideas, BMW experience or not.

Sorry I couldn't be more helpful.
Tim

[Si]

Sounds like bad plug wires or a bad boot. It could be grounding to the head, but when you hold it far enough away, it finds its path to the electrode. Those coils have a *very* strong secondary pulse, jumping a half inch is not a big deal.

Si

[bigdaddy]

Hello Tim & Si,

Thanks for your help, it is not the wire, I can move it all I want without any problem, but pulling the connector of makes the difference. It seems to run better if I have a new spark plug in.

Any way to test a spark plug for resistance or is that a stupid question?

Cheers, Joerg K.

[Si]

If it's shorting at the boot, it's going to run better when you pull it off and hold it a short distance away.

And, no. Its resistance should be infinite.

[bigdaddy]

Then changing the spark plug should not make a difference? I will try to put some electrical tap around the spark plug to see if that makes a difference, just for testing.

[Si]

If the old plug had fouled from all the missing, it would make a difference.

Electrical tape is good for what, 600v? And you will be wrapping a 20,000v wire with it? I don't know if that will help. Can't hurt to try I suppose.

Si