Ducati Monster Forum

Ok,  nothing fancy here just a simple description of the procedure.  Might be easier to print this.

Time to complete:
1- 2 hrs.  If you've never changed plugs in a motorcycle or never been under the hood of your bike figure a couple hours.  If your good with a wrench and can mentally follow this then no more than an hour.

Parts need:
Plugs of your choice, Champion RG4HC or NGK Iridium CR9EIX 3521.   Be sure to get the threaded nipples too.

Tools  needed:
3/8 ratchet and extensions.
3/8 torque wrench if desired.
10 mm box end wrench or 1/4 drive socket.
4mm or 5/32" hex key
5/8 hex sparkplug socket w/rubber insulator gripper.
11/16-3/8 socket
Tool pouch cheapie spark plug socket w/rubber insulator gripper.
Feeler gages

Note - if you are replacing the stock Champions with the same thing then you can use either the 5/8 sparkplug socket or the cheapie to remove and install.   If you are using or replaceing with NGK Iridium then use the cheapie spark plug socket because these plugs have a shorter body and the 5/8 sparkplug socket wont fit all the way down in the bore, its diameter is too big.   

Hint - If you have an old junk 5/8 spark plug or a bolt,  hammer it into the cheapie socket to loosen things up cause the cross hole has a nasty burr.   Tap the 11/16 socket on the other end of the wrench so you can get a ratchet or torque wrench on it.


Working from the right side of the bike. 

1. Run your gas tank almost empty cause you'll be lifting it all the way back.

2. If you have one use a paddock stand.

3.  Remove the saddle.

4. Lift the tank almost vertical ,and reposition the saddle up behind the tank to help support the tank as its tilted back. 

5. Remove the battery by unhooking the rubber strap and using a 10mm socket disconnect the neg term first, then the pos (red).  Be carefull around the battery pos term until the neg is disconnected. if you short anything by accident sparks will fly, if there is any gas leaking, BOOM!

6. Underneath the rubber acid tray are 4 - 4mm allen head bolts, loosen them completly.  No need ot remove the boot just flex it out of the way. 

7. Remove the terminal block bracket hex head cap screw directly in front of you. Its connected to the battery box. This is so you can slide the battery box forward to get at the sparkplug coils.

8. Grab your 10mm wrench or socket and remove the vertical cyl. spark plug coil fixing nut and gently pull the coil out of the cyl. head. (not by the wire!)

9. Shift the battery forward for clearance and depending on the type of spark plug position the appropriate socket down the hole and loosen (CCW) the plug.  Once its broke loose remove the ratchet and spin the extension with your fingers until you think its unthreaded all the way. Gently withdraw the socket and the plug should follow.  Be gentle, you dont want to bugger up the start thread by banging the plug around in the hole, the cyl head is aluminum and the sparkplug is steel.

10. Check the gap on your new plugs, manual says  0.65mm or 0.025". NGK are gapped correctly out of the box but best to check it anyway.  I put a "little" grease or oil on the threads to prevent galling, its up to you.

11. Place the new plug into the socket, shift the battery box forward as far as possible and gently lower the socket & plug into the hole. Keeping the axis of the socket straight to the plug bore gently spin the socket with your fingers "feeling" when the thread catches, spin the socket until its finger tight.  DO NOT!! put the ratchet on until you are certain its threaded in all the way by hand.  If you cross thread it and try to tighen with a ratchet you are SCREWED and the head will have to come off to repair, $$$ & time.

12. With the plug only finger tight put the ratchet on the socket and torque to 20 Nm or 15 ft-lbs. Personally I torque until the gasket is compressed then good and snug.   NGK box says 1/2-2/3 total turn.   Do  what ever you feel comfortable with.

13. The horz. plug is much easier. Do the same obvious steps but use caution extracting the coil, the wire is almost too short to allow it to fully retract. Might need to fish the wire between the airbox and radiator to get a little extra play.

14.  Put every thing back  together in reverse order, connecting the neg term on the battery last.

I switched to the NGK's because of positive comments of other posts. The motor would stumble alot a low rpms 2.5K - 3.5K.  Now its really smooth at low revs and seems to accelerate harder when its hammered [thumbsup]  - '07 S4R w/DP and Termis.

Sorry for no pics.. :(