Help: Crankcase Oil Bolt Stripped! F#$% Me!

I've done the inevitable and completely rounded my crankcase oil release bolt, really smooth operator. What's the protocol on having a stripped bolt like this removed? I just had the bike in the shop and it feels like they impacted the damn thing into the case -- it's way over torqued. Can anyone describe how to get this thing out (special tools, drill through??) I guess I'll take it back to the shop and let them figure it out if I can't get it. Thanks, and feel free to compliment me on my severely dumbass move...

I assume you're referring to the bottom allen head bolt? If yes, you might be able to use the correct sized bolt extractor in what remains of the allen wrench hole to get a grip on it to remove it.

Jerry in Deltona, FL

Definitely take it to the shop and tell them it is their fault the bolt head is rounded. That way, if anything goes wrong, it's on their dime. Otherwise, you may have to do it yourself. If it's on you, first, try a six point socket, or one of those sockets that grip the sides of the bolt head. Then try a "left hand" drill bit, then an EZ out.

Oh yeah...whadja use, a pipe wrench? :)

Take a socket slightly smaller than the correct size, maybe even a american size, hammer it on the bolt. remove as normal. You might ruin your socket, I had a bunch of cheapo sockets around when I stripped mine. This worked fine

Trust me guys, a small pipe wrench is the way to go. The wrench I used to do this exact thing was 6 inches long and good for up to one inch pipe. The thing about pipe wrenches is the harder you torque, the harder it bites. Visegrips just slip. It does not take a lot of torque to bust it loose, but more than visegrips can handle.

The easyout thing scares me. Ever have one break? It's not pretty, especially on an oil drain plug on a motorcycle with aluminum cases.

I was amazed at how well the pipe wrench worked in this situation. The wrench cost me about $5 at the local hardware store. Stock up on new drain plugs and copper washers. I've gotten into the habit of changing the plug/washer every fourth oil change, and using a good six point t-handle wrench for loosening this sucker. Oh yeah, I always use a torque wrench when installing the plug. I don't trust this soft headed bolt and pitch them out as soon as the head shows any sign of rounding. Yes, it rounds off even with the proper socket and torque wrench installation. This one bolt is one of my pet peeves with Yamaha. :)

(Yes, I know they make the head on this bolt soft on purpose so you can't over torque…)

Is the head on my new moose magnetic plug going to be prone to the same problem?

Those darn 16 pt. sockets will get ya every time.

Sometimes I can use a set of Dykes to cut into the bolt head and turn like hell to get the bolt out. this, ofcourse, ruins the bolt but does not sound like you will be using it again anyway.


Ron is right with the pipe wrench. You can also put a cheater bar (extension) to give you even more torque.

I also have used the socket/hammer approach with success.

On phillips head bolts/screws, I have gone so far as to use a hacksaw to saw a notch into the head of the bolt, then used an impact driver w/ a flat bit to turn the thing out.

If you have 12 points sockets, DEEP SIX THEM! Use only 6 point, QUALITY sockets.



'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat.

Pipe wrench will work or you could try the Craftsman clench wrench. No plug intended or ties to Sears. These Bob Vila specials are great for extracting stripped bolts or for that matter stripping perfectly good bolts. :) Along with the ball peen hammer, they have become my dad's favorite tool for working on his boat. The aftermath is disastrous! The harder you crank the tighter they grip. :D Seriously though, they will work and you can use an extension to generate more torque.

Good Luck, Keith.

[This message has been edited by kmcbride (edited August 27, 2001).]

And I thought I was the only one. Mine is about to go so thanks for the pipe wrench idea. I may need it. I would like some opinons, are the magnetic drain plugs worth it?



IMHO, yes! I use one.


'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat.

Is it number 11 in the following picture?




I had the same problem once. This bolt extremely soft and the head will round off in no time. To remove a rounded oil drain bolt, do the following IN THIS ORDER:

1. Find a small sharp pipe wrench

2. Lay the motorcycle on its side on a clean floor.

3. Place ten candles in a circle around the motorcycle

4. Paint half of your face blue, the other half yellow

5. Light all ten candles in a counterclockwise order.

6. Triple check - Lefty Loosey (?)

7. Visualize in your mind loosening the bolt with the pipe wrench

8. Check loosening direction again

9. Place pipe wrench on rounded bolt

10. CAREFULLY loosen said bolt

These bolts cost $1.40 each and should be replaced often. It also helps to have the proper 6 point socket for this thing. Good luck!

I'm referring to the 12mm hex bolt that acts as the crankcase oil drain plug. I was using a socket wrench to get it off, and the socket came fully around stripping the hexed edges of the bolt into a circle. I just called the shop, they said that they'd use vice grips to get it off, or else hammer to chisel into the head of the bolt (then hammer the thing to turn it around). This is going to be a pain to get out. I guess in the process I'll order a new magentic drain plug to replace the stripped one, oh well a little good with the bad..

Ron, that seemed like a pretty straightforward question...

Yikes...let me be the first to offer my sympathy. I'm sure there will be plenty offering salt for your wounds soon enough. Anyway, if possible, you could try regular vice-grips (the kind with the serrated teeth), clamped like mad, at a right angle to the axis of the bolt...errrr...perfectly sideways. This is a desperate solution so think twice before using. If you can't get a right angle on the bolt, the most likely case, I'd say skip the vice-grips and get an easy-out. The theory on this is to drill a pilot hole in the face of the offending bolt, and just crank the easy-out-thingy into the hole. The easy-out has a reverse thread type of shape to it which, as it taps itself into the bolt, gets harder and harder to turn until the bolt spins free...well at least thats the theory. This can be dangerous in your situation as you need to get the pilot hole as centered as possible and not injure any of the case threads by drilling the pilot hole in the bolt. As I remember, the drain bolt is at least 1/2" so you should have plenty of meat left to get the job done. By the way, you should be rippin the bonehead at that shop of yours.

Easy-out's (as I've always known 'em) are also known as spiral flute screw extractors. A sample can be found on at, enter 2566 (the catalog pg. #) and hit "find".

Good luck dude!!! Gary


'99 WR400 with CA plates...ooooh yeah!!!

This just happened on my '00 WR about a month ago. I was just about in tears as I felt the socket starting to slide around the bolt! I wound up using vise-grips. Got them on the nut at 90 degree angle as tight as I could and started tapping lightly with a small hammer. Took about half hour but it finally broke free. Guess I got lucky!! (Thank God!) I installed a Moose magnetic plug - haven't changed oil yet so I don't know how much junk it has picked up. One note, the parts guy told me not to use the washer that came with the bolt and to use the original. He said this info came from Moose. The new one is quite a bit thicker than the factory washer. Anybody else heard this? :)

as far as the magnetic drain plugs go i took my standard plug and introduced it to a couple of magnets for a while. Then guess what after i did that. i was able to pick up screws and nails. So i am sure that it will catch what i needs to in the crankcase. Same theory with screwdrivers. Just thought that you all would like to know.


If life is not a blur. You aren't going fast enough

Pipe wrench works good if you can get a good grip on it. Impact drivers Rule! Not air Impact guns, Impact drivers twist when you hit them with a hammer, so they put rotation on the fastener while driving down so they dont slip and the banging loosens the bolt. I have ground slitts in stuff and used the driver on it. Also you can weld a nut to the head of the bolt and wrench on that. A butane tourch shold be able to get a little heat into the alum case to expand it a bit too! You may have better luck with it after the bike is good and hot, the alum cases shold expand more than the steel nut. That may be why its so tight, the bolt was tourqed when the bike was hot. I would definatley try welding a nut to the head of the bolt before trying to use a very good snap on blunt nose easy out. Easy outs are last resort and work best for those who have used them before.

Do Not Use the Thick Washer!!!

The thread in the case is relieved on one side to help oil drain completely out.

I used the thick washer in conjunction with the shorter magnetic drain plug...


1 Time sert later I called our bou Ty Davis and he said he knew there was a problem and I could get a thin washer from him.

OH well, live and learn.

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