WR400 Basic Maintenance Help

5 replies to this topic
  • codlord

Posted October 13, 2002 - 06:20 AM


I am attempting to learn how to maintain my WR400, starting with the basic oil/coolant/plug change type things, I have a Clymer manual but can someone help me with a few questions:

1 - What type of spark plug spanner do I need? I have a deep socket that will fit but cannot get a socket extension down the case due to the frame being in the way.
2 - Is there a secret to taking out the oil strainer (not the filter)? The manual says to undo the hose, then the bolt, but how do you get the hose off, it's only a tiny bit of hose and there is no give in it to be able to get it off the oil strainer bolt without bending the lower bit of pipe that it attaches to.
3 - After changing oil I am getting a tiny bit of seeping from the oil strainer bolt - I did not change the copper washers - is it important to do so or is there likely to be another problem?

Thanks in advance

  • HAY

Posted October 13, 2002 - 07:31 AM


For changing the sparkplug I use a sparkplug socket with a 3" extension and my ratchet. You can drop the socket down onto the plug, then snap the extension into the socket, and finally the ratchet to extension. It all has to be done one at a time to work though. Heres the tricky part. To get the plug out all the tools must be taken apart reverse order then i use a hanger and bend it so that it has a hook at the end. The hook has to be just right so that you can stick the hook into the socket and it catches so you can pull it out. You have to have a plug socket with the little rubber deal in it. I believe the bike comes with a tool that makes this much easier. I bought mine used and didnt get any tools with it. As for the strainer. I"ve checked mine once and it was fine so I havent really worried about it.

  • tk421

Posted October 13, 2002 - 08:39 AM


1. I have the YAMAHA spark plug tool, but prefer a spark plug socket and 3” extension as mentioned above, also a longer extension to get around the frame. The tricks I’ve found: Remove the rubber washer in the spark plug socket (helps when removing the socket), after dropping the socket down in the hole use the 3” and a LONG extension. To get around the frame, I connect the socket and extensions loosely (you’ll still be able to torque the plug in properly), this allows me to work around the frame. After I get the plug loose, I then remove the socket with a small needle nose pliers. To remove the loose plug and install the new one, I use a 12” chunk of clear rubber hose. The hose just fits over and grabs the porcelain part of the plug so you can turn it the rest of the way out. It also allows a better feel when threading in a new plug (prevent cross threading).

2. Be sure the hose clamp is way loose. It’s not easy to do, but the oil strainer will come off.

3. It’s time for a new copper washer, not necessary though for every oil change.

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  • MN_Kevin

Posted October 13, 2002 - 08:50 AM


You can use a universal joint as well on your socket wrench. I have never used one, but there is those "Wobble" joints - it acts as a universal but it allows a slight offset. The wobble joint fits between the socket and the wrench/extension.

As for oil line leakage, your hose clamp is still on, right...???

  • WR_Jason

Posted October 14, 2002 - 09:22 AM


I use a 3" Wobble extension. The Wobbler gives about 3 degrees of wobble. I dont know if sears has them or not but most other guys like SK from NAPA, Matco Mac, and $nap on have the wobblers. I use an extendable magnet to pull the stuff back out. I keep the magnet in my camel back, its super strong and can pick up a 2/12 lb hammer! You would not belive how many master link clips, nuts bolts I have found just by waving that thing along the ground!!! :) .
It dose sound like time for a new copper washer, you might be able to find one at the plumbing section at the LHS. They tend to mushroom out if you put to much torque on them but they are ment to be replaced once compressed.

  • Rich_in_Orlando

Posted October 14, 2002 - 10:22 AM


Before you try to remove the oil strainer hose, take the bolt off the bottom of the line (the part that goes into the crankcase.) That frees up the hose so you can move it around. Don't forget to keep track of the o-ring after you loosen it up.


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