R27 Ignition system

Restoration forum Bmwbike.com
Post Reply
Holger Willrath

R27 Ignition system

Post by Holger Willrath »

Four questions:

What is the capacitance of the condenser of the R27?

Will any Bosch (or other)automotive condenser that has the right capacitance and fits in the space work OK?

I have been given contradictory advice regarding spark plug caps. Do I need zero resistance caps or will the standard 5K Ohm caps work OK on the R27?

I have never been able to use a xenon timing light on my R27, even though I have powered it externally with a 12 V battery. Only my dull old neon strobe light works. Is this normal or just an indication that my ignition system is faulty and the current through the pickup is too small to trigger the xenon tube? The spark bridges a gap 12-15 mm.
Dave Thomas

Re: R27 Ignition system

Post by Dave Thomas »

Hello again Holger,

The answers to your questions can be found at Craig Vechorick's web site (I'm e-mailing you the URL since this site won't post URLs). Essentially, any condensor that will fit the space will work, and Vech recommends a Ford part, which I have been using with excellent results. He also explains that the magneto system needs 0 resistance between the coil and the spark plug. I have been using an original non-resistor plug cap and my R26 always starts on the first kick and runs like a champ. It is considerably harder to start with the 5K ohm cap installed. Vech also sells the non-resistor caps. Regarding the timing light, I have been using my xenon light, which is switchable between 6 and 12 volts, on the 6 volt setting and I get a good strong flash. I'm begining to wonder if you have a weak coil.

Good luck!

Dave
Post Reply