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Bridgestone 350 (175/200's too) Electronic Ignition Conversion

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OldSwartout:
Mount the pickups and point cam/rotor and connect the pickup wires to the harness wires in the alternator. Connect the new power wire (blue) to both red wires to the pickups. Connect the other wire from the right pickup to the black harness wire and the left pickup to the white harness wire. The color of the wires from the pickups varies, depending upon the model of Dyna S purchased. (Ignore the Black and White color wiring connections in my photos, they are reversed. Oops).  Attach the harness ground wire (if still using the internal ground wire). 

OldSwartout:
Preliminary timing adjustment:
Set the engine to one cylinder firing position using the timing pin or dial indicator (.135 in./3.44mm BTC). Then with the set screw loosened slightly, rotate the rotor until the magnet visibly lines up with the bump on the ID of the pickup, then tighten the setscrew to lock it in place. Note: I suggest you pull the rotor out at this stage and apply Loctite to the ID and to the setscrew. You will have time to make adjustments before the Loctite sets.

Reconnect any remaining disconnected wiring back to the 350 wiring harness under the seat. The blue power wire (or re-purposed black/white wire) will connect into the harness blue power wire. Mine had an extra open spot in the 4-way connector under the seat, but you may need to just splice it in with a crimp connector.  Reconnect the white & black ignition wires, the brown alternator wire, and bluegreen and yellow to the rectifier. Don’t forget the ground, either the original black/white or your new ground from the engine case must be connected back to the battery ground or frame.

Final timing is similar to points except you can’t use a test light. Instead, watch for a spark. It is easiest with one of the ignition test gap tools available at auto parts stores for less than $10, or open the side electrode on a spark plug straight out because you can easily see and hear the spark. Set the engine crankshaft to the correct timing location using the timing pin, then with the transmission in gear (5th or 6th  ) and the ignition on, rotate backwards, then back forward slowly. It should spark just as the pin drops into the crankshaft notch or the piston reaches the correct distance BTC. Adjustment can be made by loosening the setscrew on the rotor and moving it, or rotating the alternator. Once one side is done, adjust the other side by moving the pickup as necessary. This may be a little more tedious than adjusting points, but once it is done, it should not require maintenance unless you move the alternator (no more point gap filing or adjustments).

OldSwartout:
To double check your timing you can use an automotive strobe timing light. Due to the small diameter of the rotor, it’s difficult to get an accurate visual mark alignment across the gap to the pickup, so I made a crude pointer and placed timing marks on the OD of the alternator using the timing pin notches.

OldSwartout:
Nice Spark:

OldSwartout:
Additional notes:
  
If your spark is erratic, be certain the rotor is set deep enough on the old point cam to align the magnet with the axial center of the bump on the pickups. I didn't realize this at first, so most of my photos show the rotor located at the end of the point cam in error.

The Dyna web site has a brief troubleshooting document.

Dyna requires 3 Ohm or higher resistance coils.  The BS350 coils are roughly 5 Ohms, so they should be fine. Aftermarket coils, Dyna or others, could be used for an even hotter spark.

There is a photo in the gallery section of a conversion I did to a 175 with a 1/2 speed alternator, which requires a 2 magnet rotor and a special shortened pickup. http://bridgestonemotorcycleparts.com/index.php?action=gallery;sa=view;id=291  I modified a KZ1000 system, but it would be much easier if you purchased a Dyna S system for the Honda GL1000, which comes with the 2 magnet rotor and short pickup.  For a 175 or 200 with the engine speed alternator, the conversion is similar to the 350.

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