J Vreede
XS650 New Member
There’s a description of my project bike, in the introductory post I made 26Jul, that I have questions about. The bike came to me basically finished but for the electrics. It was running when I first bid on it (on the NZ equivalent of Craigslist), but it was withdrawn from auction because its Pamco ignition had blown up. I figured it was just the original ‘74 voltage reg/rec and/or the cobbled up wiring mating the later engine to the earlier wiring loom, so I bought it not running and started collecting the materials, like a MOSFET reg/rec and wiring stuff from Revival Cycles, to do a complete rewire, as I want it to be as reliable as possible.
I didn’t recognize it in 2016, but it’s pretty apparent looking back through the archives, that 200W permanent magnet alternators, big coils and Pamco ignition on a std ‘74 XS regulator/rectifier were mismatched. The seller bought another Pamco w/advancer to go with the bike, probably amongst the last Pete sold, as by the time I got around to looking at how to install it, he’d stopped selling them. Other events then overtook any further work on the XS, until now.
My question is what actually was mismatched about these components and why? Can someone who lived through that period pls tell the story?
Things that come to mind from reading past posts:
Thanks - jv.
I didn’t recognize it in 2016, but it’s pretty apparent looking back through the archives, that 200W permanent magnet alternators, big coils and Pamco ignition on a std ‘74 XS regulator/rectifier were mismatched. The seller bought another Pamco w/advancer to go with the bike, probably amongst the last Pete sold, as by the time I got around to looking at how to install it, he’d stopped selling them. Other events then overtook any further work on the XS, until now.
My question is what actually was mismatched about these components and why? Can someone who lived through that period pls tell the story?
Things that come to mind from reading past posts:
- PamcoPete’s musings that Pamco failures seemed to be associated with the PMA’s and big coils – was that inherent in this combination or was it a Pamco failing?
- Are 2 big coils something that the Pamco ignition just can’t cope with or are all the alternate electronic ignitions similarly affected?
- Is there some reason (other than space) that coils with dual leads (wasted spark) seem to be preferred or recommended by the ign. mnfr’s?
- The bike doesn’t need a 200W alternator to run and its obviously going to dump some (most?) of it as heat, so it needs a good reg/rec, but my Ducati Monster has a 520W alternator, doesn’t have a Mosfet reg/rec and doesn’t blow up its electrical components. Is there anything inherently bad about PMA’s on XS650’s?
- Seems that a number of the last Pamco units were defective. Even though I have a new (untried) one, should I be looking for an alternative for reliability’s sake?
- Given the bike has a 200W PMA that I can't replace, what other electrical components would you choose now, so that they’re balanced and reliable?
Thanks - jv.