R51/3 retard/advance inertia piece;

Restoration forum Bmwbike.com
Post Reply
Michael Steinmann

R51/3 retard/advance inertia piece;

Post by Michael Steinmann »

HELP. I have loosened the small bolts that are keeping the cheeks with springs in their grooves. I also know that:
"Die einstellschrauben werden in der Fabrik plombiert. Werden diese schrauben gelost, so verandert sich die Motorleistung. Es wird daher dringend vor Eingriffen gewarnt".
This is a quotation from the "Noris Zund-Licht AG" book. So what should I do now? Many thanks in advance for any help!
Micha.
Allan Atherton

Re: R51/3 retard/advance inertia piece;

Post by Allan Atherton »

Just put the screws back where you think they were previously. Then check full advance with a strobe light to make sure the F mark is not being exceeded. If exceeded, reposition the screws to increase the tension of the springs.

Michael Steinmann

Re: R51/3 retard/advance inertia piece;

Post by Michael Steinmann »

Thanks Allan, I will give it a try.
Ian MacDonald

Re: R51/3 retard/advance inertia piece;

Post by Ian MacDonald »

Is is difficult to adjust the advance springs without a jig to hold the advance assembly.Can you get someone with a Lathe to turn you a piece that replicates the end of your camshaft. Bolt your assembly onto this so that you can manually replicate the operation of the advance mechanism. Set the springs such that at zero advance they are just under tension i.e. removing any slack in the assembly. Check this adjustment at full advance on the bike as described by Alan Atherton to ensure you are reaching BMW's designed advance, increasing spring tension if required. Takes a little time but well worth the effort to get it right. To date I have been unable to find any original set up procedures for the advance units. The above has worked for me.
Post Reply