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jcm3

Oil plug pulled out?

18 posts in this topic

I was changing the oil in my YZ426 last weekend and the drain plug pulled out. It can still tighten, but seems to have pulled out the threaded part that the drain plug actually threads into.

It started leaking, so I assumed it was the copper washer. I ordered two and was suprised when it didn't fit. It didn't occur to me that the drain plug was actually inside of the threaded housing. I checked the parts store to see if that is a removable part, but it doesn't appear to be. So, I don't know if I am supposed to have a washer or something else under it.

Any ideas what I should use to help seal it up and stop it from leaking? Should I put a washer under the larger threaded part? (with the coarser threads) Should I use Lock Tite?

I have never seen this before on my 10 or so motorcross bikes that I have owned, and I didn't tighten the hell out of it.

Here's a pic: drainplug.JPG

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an oring would be ideal but your picture doesnt show me what i need to see to be able to say for sure.

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Did that come from the frame?

No, from the bottom of the engine. It is the lower drain bolt.

Not sure how it pulled out, I can try to get a pic if that would help.

For now I just put about four or five laps of teflon tape around it, and am keeping an eye on it.

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Still leaking. %$#@!~

I don't know if the housing part needs a washer or not, I'm thinking about trying that next with a heavy amount of loc tite. I don't see a need for removing the housing part in the future, just the oil drain bolt itself. But, I can't find any microfiche diagrams that even show it.

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One question. Does the oil drain bolt usually thread directly into the bottom of the case, or do other 426's have a plug like in my pic that threads into the bottom of the engine, and the oil drain plug plugs into that?

It appears to have an aftermarket oil drain bolt with a magnet, but wonder if the previous owner stripped out the hole or something and put some kind of an adapter in that is like a big heli coil plug or something.

No idea, since I don't know anyone who I can compare with.

I'll have to take another pic, so I'll be draining the oil AGAIN.

I'm tempted to use something more permanent, but if I do, and it still leaks, then I'll be screwed.

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The drain bolt is listed as an M12x59, and from the look of the picture, the thread on the part that unscrewed from the case looks to be that size. This makes me think that what you have is something made up to use a smaller, possibly magnetic, drain plug. If I'm right, the correct plug and gasket should fix it.

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OK, I think I figured out what is going on, and it is NOT good. I took the gasket that I ordered, and it fit the blue magnetic drain bolt in my pic perfectly. So, it is the correct bolt, but of course, what the hell is the other part.

I got under the bike and took a pic. I think what happened is that the bolt was probably stripped out by one of the previous owners, who probably drilled and retapped it for a 'plug' of some kind. (the thing that the blue drain plug in my pic screws into.

Now, the bad part. I got under it and took a pic, and the case is cracked. This probably happened because the hole was drilled out, and is less strong than it used to be. This is also why it was seeping oil, as it was not a good seal.

My question is, can this be welded, or it the entire case magnesium? I am hoping that I can put the bolt in and then have the outside case welded to seal it. I'm really not in the postion to get the case or cases replaced, and am a little bit bummed at the moment.

Any input is appreciated.

Here's a pic:

drainhole.jpg

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ps - Sorry for the slow download of the pages on my website, I only get something like 128 upload in my zip code. %$#@!~

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pic doesnt show up. if you can snap a pic of the other side of the modified bigger plug and the hole i can recommend a few thing as well as some others here.

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The crankcases are aluminum. That area would actually lend itself to being repaired without disassembly if the welder is really good.

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The crankcases are aluminum. That area would actually lend itself to being repaired without disassembly if the welder is really good.

Thanks, that is a big relief. I really can't afford new cases at this time. I'll have to see if they can reinforce it somehow so that it doesn't split again.

Or, might it make more sense to just weld it shut, reinforce it, and then drill/retap for the original drain plug size? Otherwise I'm concerned that since it is already split, that it might be tough to close up the crack enough so that the threads will seal correctly.

pic doesnt show up. if you can snap a pic of the other side of the modified bigger plug and the hole i can recommend a few thing as well as some others here.

Sorry, I'm an IT guy and am having a major $hitstorm at work right now and am working on several outages. I had to turn my website off for a short while because it was grinding my connectivity to work to a halt. I have it back on right now, but may have to turn it off again. Thanks for the help, and sorry for the inconvenience.

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Or, might it make more sense to just weld it shut, reinforce it, and then drill/retap for the original drain plug size?

That's how I'd do it.

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That's how I'd do it.

Thanks for the input.

Edited by jcm3

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Had a slightly better and easier idea. I am going to just screw in the aluminum plug, have a bead welded around the top, and then have them clean up the crack on the side. Part of the problem is that the plug is not held in place, so it moves around and tries to screw in when I tighten the oil drain plug.

So, this should shore it up nicely and hopefully be a permanent fix.

I just hope that the heat doesn't cause the gaskets between the cases to start to leak, but I guess that's a possibility. Fortunately the drain hole is offset a bit, so I'll just ask them to try to tac it as they go around to try to reduce the heat as much as possible.

I just talked to a machine shop guy, and directed him to this thread to see the pics. He also felt that it was a good idea, so we'll give it a shot Thursday morning and hopefully have the bike ready for Milestone MX part by the weekend!

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That's essentially the same thing as welding it shut. What you may run into is that the welding may distort the smaller hole the drain plug is in so badly that it will need to be drilled/tapped a size larger.

The advantage is that it leaves an already milled flat surface for the drain plug.

There are no gaskets between the cases. They are sealed with a sealer similar to RTV silicon.

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That's essentially the same thing as welding it shut. What you may run into is that the welding may distort the smaller hole the drain plug is in so badly that it will need to be drilled/tapped a size larger.

The advantage is that it leaves an already milled flat surface for the drain plug.

There are no gaskets between the cases. They are sealed with a sealer similar to RTV silicon.

Do you think I should have him weld it with the drain plug in for the extra support, just in case?

And, do you think that the heat from welding will cause a leak due to possibly melting the sealer between the cases?

I'll have to ask him to try to tack it as he goes around and not run one continuous bead. :)

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Let him look the situation over and decide how to deal with it. The sealer may fail, but it's not that likely.

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