Re: Boyer Ignition

Posted by Hendred on Jan 15, 2014; 6:04pm
URL: http://silk-motorcycles.221.s1.nabble.com/Boyer-Ignition-tp5000987p5000992.html

Thanks for the information on the bob weights.  Do you happen to know at what engine speed the mechanical advance units reached full advance?

My understanding is that the advance varies slightly depending on the porting used, with the Peter Green  porting advance less than for the earlier versions. On a system achieving full advance at 2000rpm I would expect high rpm power to be less affected than low rpm.  Having said that, looking at two stroke ignition maps they seem to reach full advance by about 2000 rpm and then reduce the advance at high rpm (usually above 6000 rpm so shouldn't be a problem for a Silk!).  Some Villiers engines had fixed ignition which worked ok too.   I suspect the ignition retard helps starting (reduces kick backs) and improves idling, after that it isn't too important whether full advance is achieved at 2000 or 3000 rpm.

It will be interesting to hear the experience of users of Boyer and Pazon units in practice.