Minor YZ/WR maintenece issue (spark plug)

7 replies to this topic
  • Airastro

Posted June 16, 2000 - 01:18 PM


Now that we all own four strokes changing spark plugs is almost a thing of the past. I adjusted my valves the other day and in doing so I removed the spark plug. I noticed that the outside and threads of the spark plug were wet and showing signs of corrosion. I am sure this came from washing the bike, and I dont use a prussure washer. My bike only has about 20 hrs on it so it is fairly new. I guess the easy way to remedy this is to remove the spark plug cap and spray a little WD-40 down the hole to displace the water. This obviously is not a major deal, as long as the corrosion doesnt get to bad and fuse the plug to the head, I just wanted to inform members of my findings

  • Clark_Mason

Posted June 16, 2000 - 02:32 PM


When you install your plugs put a little high temperature anti-seize on the threads. This will fight the corosion and make getting plugs in and out easier.


  • RodH

Posted June 18, 2000 - 01:34 AM


When I wash mine I always put some tape over the hole on the right side of the head. This hole goes straight to the plug, so with it covered, and the plug cap in place there is no chance of water getting in there during washing

RodH Canberra, Australia<A HREF="http://www.400thumpers.oz-au.com" TARGET=_blank>
400 Thumpers Australia</A>
2000 WR400F See Photo's and Modifications

  • 1fastYZ450

Posted August 30, 2011 - 06:00 PM


What is the hole on the right side of the head for?

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  • Sknight

Posted August 30, 2011 - 07:31 PM


The hole is a drain for the spark plug well so if water gets in it can drain out hopefully before it gets high enough to ground out the ignition. Ironically it does allow a straight path especially if you use a pressure washer or even a garden hose with a sprayer.

Another tip, don't drench your bike then shut it off. Run it for a few minutes to allow those nooks and crannies to dry out.

  • Krannie McKranface

Posted August 31, 2011 - 06:13 AM


The right side hole can also be used as a compressed air passage, which is what the factory reccomends.

Squirt WD or Brake fluid on top of the plug to loosen debris, then shoot compressed air up the hole to remove all debris.

ALWAYS use anti-seize in any bolt (plug) that screws into un-like metal (steel into aluminum or brass)

  • 1fastYZ450

Posted August 31, 2011 - 05:16 PM


Thanks for the info. I thought it may have been a breather port. But for next time, I'll be more carefull on how I wash the bike! But then again, it will be tough not bury it in the mud and water....Thats waaay too much fun!

  • 2in2out

Posted August 31, 2011 - 06:23 PM


CRC 6-56 works well too. I give a little squirt in the hole after washing.


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