Spark Plug Drainage

New to the to dirt bikes in general...

I have a WR450 and was starting some mods tonight. Got the AES kit installed and some other stuff. I removed the spark plug to see how it looked and was surprised to see lots of rust around the nut part of the plug. I've had this bike about 6 months...

I was checking out what looked like a drain hole at the bottom of the freakin deep spark plug hole. I assume it lets in a much water as it lets drain. Does anyone plug that hole while you're riding so no water gets in? Seems like it does more damage than it helps.

BTW, what tool are you guys using to remove the spark plug. I was a little challenged with a typical 5/8 with long extention.

Any guidance for a newbie is appreciated!

I got the spark plug tool with the bike when bought new from the dealer. If you bought it new and didn't get one, go back to the dealer and have him make it right.You should have gotten a spoke wrench, and a shop manual too! As for the drain plug,leaving it open is a good thing...washing the bike is where you get most of the water in there anyway.

Buy a couple cans of compressed air (available at any office supply store). After washing or riding in wet conditions, blow out the drain hole to get rid of the moisture. It can get pretty nasty in there if you don't.


I have the Yamaha spark plug tool, gets the job done fast. Just plug the hole when you wash the bike. And is your plug 6 months old??? :thumbsup::lame:

Hey guys...thanks for the help!! I did not get a plug removal tool from the dealer. I made the mistake of getting a good deal a few towns over and won't go back just to get the tool, but I will remember that for next time.

"And is your plug 6 months old???"

And Yes, I'm on the original plug. Its due for a change but was not hampering performance that I could tell. But I'm just an old guy trying to keep up with my kid on the weekends. I might have 150-200 miles total on the bike.

Thanks again for the help!!


I use a leaf blower after washing my WR every time. I never checked for rust yet? I just might now...... :thumbsup:

What concerns me with the deep recess the plug sits in is when you remove it you can't actually see what is inside & dropping into the cylinder on top of the piston, bits of rust & dirt. I normally try blow it out first with compressed air but I'm sure when the plug wrench is dropped in & fitted it knocks off some debris which ends up in the cylinder.

I use a 5/8 plug socket with a built in wobble joint, a 6" 3/8 extension and ratchet.

I plug the hole with a golf tee when washing the bike.

I use air from my compressor in the hole to help get the plug cap off as well as to blow any crap out.

I also use a shortened golf tee to plug the hole when washing. My bike must be jetted right because I've got the stock plug in my '05 with 1200 miles on the clock. I'm gonna replace it just out of guilt when I check valves at 1500 mi.

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