Coils question

fishandchips

XS650 Enthusiast
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just wondering. The points bikes seem to have a permanent live just like the tci version. However the points bikes have two wires for the points, so each coil seems to work independently (grey and orange wire).

The tci bike has a red and white power wire and just one orange wire. Do the plugs spark even on the exhaust? Since there’s no independent wiring and no distributor.

Am I missing something :shrug:
 
Yes, the later TCI equipped bikes spark the plugs at every TDC stroke, creating a "waste" spark if that TDC stroke happens to be the exhaust stroke. The points bikes fire each coil separately and only at TDC on that cylinder's compression stroke.
 
just wondering. The points bikes seem to have a permanent live just like the tci version. However the points bikes have two wires for the points, so each coil seems to work independently (grey and orange wire).

The tci bike has a red and white power wire and just one orange wire. Do the plugs spark even on the exhaust? Since there’s no independent wiring and no distributor.

Am I missing something :shrug:
Something to remember for any engine... if the iggy trigger is crank driven.... it'll have a waste spark on the exhaust stroke. Only with cam driven timing will it only fire on the compression stroke.
EDIT: There's exceptions to the cam driven spark. My main point is that a crank driven iggy will always have a waste spark because it triggers every 360deg. ... and don't even start on 2 strokes... :rolleyes:
 
Last edited:
What’s an iggy trigger Jim? Googled it and got

BE15B6A8-6494-46EE-A583-721CF137E234.jpeg
 
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