Dom,
When running a mag and the Light Speed EI they recommend the timing be set on the mag with a timing light as they do for their unit as well. If the shop set the mag timing with a buzz box that could have changed it. I run the same set up. I get almost no drop in rpm when the mag is shut off. This is due to the fact that the mag mostly sparks in the shadow of the longer hotter sparking electronic ignition. It is my understanding that the Electronic Ignition is doing 90% of the firing of the gases in the cyl.
I would retime both the EI and the mag and see what you get. I have the hall effect module and you use a simple automotive timing light with marks on the fly wheel.
It is pretty easy to do..
FWIW..
Randy
Snarr
N694RS
235/320
"Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible"
-Simon Newcomb, 1902
From: Gary Casey <casey.gary@yahoo.com>
To: lml@lancaironline.net
Sent: Thursday, December 29, 2011 2:10 PM
Subject: [LML] Re: Lightspeed Ignition
Dom,
I'm sure the most common cause for this is a change in ignition timing. I assume the mechanic left the Lightspeed system alone, but did the normal routine of resetting the timing of the mag. If the two timings are exactly the same you will likely get the same drop on each, or maybe a little less drop on the Lightspeed. I've observed that most annuals include resetting the timing, but rarely will the mechanic state what it was before the change, which would be very useful information. I'll bet he advanced the timing of the mag by maybe 2 degrees. Just a guess :-)
Gary
Um – er - (headscratch) – fellow LMLer’s – since the annual performed by maintenance outfit (not necessarily significant) I notice I get a drop around 80 RPM on the Lightspeed ignition during run-up, whereas before it was barely noticeable.
Been wondering why. Changed my iridium plugs two days
ago just as a starting point but no difference.
So thought I would ask the experts herein.
Thanks
Dom Crain