Coil on Plug Setup

This mod removes the coil off the right side of the frame, and instead moves it on top of the spark plug. It gives the bike a cleaner look and allows easy access to the carb. The coil on plug setup has slightly more primary resistance and slightly less secondary resistance than stock. Doug Dubach runs a coil on plug setup on his YZ426 race bike (he uses a Suzuki Hayabusa coil), and the 03' YZ450F comes with a coil on plug setup stock. The coil I used came off of a 99' Continetal. My bike runs great with better throttle response and hotter spark.

Installation Instructions:

  1. Remove the seat and tank
  2. Remove the stock coil and wire assembly
  3. Remove the spark plug and install the screw on cap on top
  4. Reinstall spark plug
  5. Reroute the new coil wires under the frame
  6. Drill a hole in the aluminum motor mount and attach original ground wire and new coil ground wire with 6mm bolt and nut
  7. Attach white wire on new coil connector to orange wire on original harness using shrinkable butt connector (slide shrink tubing over wire before crimping)
  8. Heat shrink all shrinkable tubing and butt connector ends with a heat gun
  9. Install convolute tubing over wiring
  10. Cut spark plug boot off of original plug wire and snap it on to the new coil
  11. Pull throttle cables aside and slide coil into place on spark plug
  12. Reinstall seat and tank
  13. GO RIDE IT!

Mike Dean (from Thumpertalk.com) sells a complete kit for $45 that includes everything you need to install the coil on plug setup. The setup I installed came from Mike Dean, and it had everything you need to install the coil on plug. He sells the kit for $45 and comes with new coil, shrinkable tubing, 6mm bolt and nut, screw on spark plug top, zip ties, convolute tubing, and detailed instructions and pictures. To purchase the coil on plug contact Mike Dean @

Mike Dean
1727 Apollo circle
Stoughton, Wi 53589
608-873-5240
608-576-8745

Here are some pics below of Mike's setup installed on my bike:




Stock setup



Stock coil



Spark plug cap modified to fit the new coil



New coil mounted on spark plug cap



Screw on top installed on the plug



Coil on plug completed (notice the empty space on the right side of the bike!)