How to get to spark plug

Hello, I purchased a nice used WR250R this past spring and am thinking about winterizing it before storing it until next Spring (I live in Wisconsin). One of the things I want to do is put some oil down through the spark plug hole to lube the cylinder. Can someone please give me a step by step procedure on how to get to the spark plug on this bike? What needs to come off and any tips on the removals? Which side of the bike do you access the spark plug from for instance. I understand that there is also a cap over the spark plug. Any special instructions on removing the cap? Your help would be much appreciated. Thanks.

You have to unbolt and move gas tank out of way to get to spark plug.

The plug is deep DEEEEEP into the head with large cap and coil over it that may take plenty of
muscle to POP off the first time you try it.


It's a royal PITA.

But if I can do it, surely you can too.

Which side of the bike do you dig into or do you have to remove plastic from both sides? Any tips on removing the cap over the sparkplug? Does it pop off? screw off?

Remove seat and all plastics. Gas tank off to. Be careful of the fuel lines etc attached to fuel tank. I use a bungy cord and strap the tank off the tranny side off the motor hanging crom the bars. The coil pulls off, but does take some muscle and twisting to get it out.

Is there a wire or anything else attached under the cap that I need to be careful of when removing?

Under the coil? No, just like in a car when poppin off the spark plug cap.

Thanks for the replies. Now have to get the R ready for winter.

if you have compressed air nearby you can use that to help you. Blow it in from the side of the cylinder (there's a small hole on one side). At the same time pull the cover. the compressed air helps out a bunch

OK, This may help.

After you remove the seat, the left and right side covers, the left and right plastic "wings" and remove the fuel tank, (or set it aside) you look down on the top of the engine from above and see the top of the coil and its connector fully inserted into the upper engine.



Here is a close up of the top of the coil assembly.



Twist and pull straight up on the top of the coil assembly and remove it. Mine wasn't that hard to remove, but my bike had 7k on it in only about 3 months after it was purchased. At 7k it is spark plug replacement time. If you ride a lot less, then your coil boot may have had more time to stick itself to the metal, but you shouldn't need any tools to pull this thing out.

When you pull it out it looks like this:



Meanwhile, back down in the hole, you should be looking down on the top of your spark plug. DO NOT REMOVE IT YET!



Look for the little hole on the right side of the engine and shoot some compressed air, or in this case that computer "dust off" spray air into the hole. The crud that has settled inside of the plug recess will shoot out the top from where you removed the coil. Once you are satisfied that you have cleaned out the recess, then remove the spark plug, (5/8" SPW). Since this is a critical part that is very hard to get access to, I would replace the spark plug with a new one any time you remove it. Broken or stripped threads would be a new nightmare. Tighten carefully about 1/2 turn after the metal crush gasket touches the head. Shop manual puts the torque at 9.4 ft/lb. When I removed my old plug it came out very easily, these are not cranked down in the head very hard at the factory.




Prior to replacing the spark plug, coat the spark plug threads with anti-sieze compound. Coat the spark plug porcelain and the sealing portion of the coil boot (the part that gets stuck to the engine metal) with dielectric grease. This will help with EZ removal next time.

Otter thanks for the clear and concise write up. You might want to consider writing manuals as this is probably one of the better descriptions I have seen.

Thanks

very nice explanation

Thanks Guys.

OTTER

From a guy about to change the plug for the first time thanks Otter!