Stripped my "main" oil drain bolt... or crankcase?

9 replies to this topic
  • Wrex Everything

Posted May 22, 2007 - 12:08 PM


I'm the proud owner of an '05 WR450, but I'm worried I may have inadvertenly hurt my machine while changing my oil. So... I change my oil and filter last night, fill 'er back up with Yamalube, then give a couple extra cranks on my main oil drain bolt (12mm bolt at bottom/rear corner of crankcase) to make sure it is nice and tight. As I'm doing this, the bolt starts to spin more freely, and so I think that I stripped it.

I have not pulled the bolt out to inspect yet b/c this all occurred late last night, but what are the chances that I've actually stripped the female (crankcase) side threads and not just the bolt itself? If so, what type of recourse do I have to resolve this. Can you "re-tap" your crankcase?

I'm worried now (sitting here at work), please give me a holler if you guys have any ideas/experience with this. Thanks.

  • BajaFool

Posted May 22, 2007 - 12:20 PM


Chances are excellent that you stripped the threads in the case. Don't panic. Any competent mechanic can repair the damaged threads using a HeliCoil thread insert or similiar type of product . It should not take much time and should not cost very much money. This happens a lot when a mechanic over tightens the drain plug on the oil pan of an automobile.

  • xr250ryder

Posted May 22, 2007 - 02:31 PM


No offense, but didn't you look at the torque value on it before you started reefing on it? And any mechanic can fix it, if not you might be able to re-tap it.

  • Wrex Everything

Posted May 22, 2007 - 03:06 PM


Yeah, actually the reason I went back to this particular bolt is that the guide indicates that it requires a higher torque than all the others involved in an oil change. Tell you the truth, I didn't even torque on it that hard...

  • xr250ryder

Posted May 24, 2007 - 05:55 AM


Hmm, thats weird... maybe it was bad to begin with? Did you take it to a mechanic?

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  • marty b

Posted May 27, 2007 - 12:09 PM


you shre its the case and not the plug the plug should be slightly softer for this reson

  • tdave

Posted May 28, 2007 - 08:29 PM


i did the same thing. i was wondering how you got this fixed or if you have yet? i was looking online at looks like a better option than the helicoil....let me know what you did as i will be getting mine fixed this week.

hope that it turned out well!

  • marty b

Posted May 29, 2007 - 01:49 PM


look up heli coil they work awsome


Posted May 29, 2007 - 08:32 PM


I went through this recently the night before a big

I had just finished doing my usual pre-riding inspection, maintanence....
Then came that #12 ol drain bolt at rear of engine....

Did what you did, twisted a ***** hair to hard lol.

The fix....

Layed the bike the bike on it's side and re-tapped the hole the same size as the exsiting hole. I still use the same bolt!

No problem after 400 km.

Also if you drill a 1/32 hole in the bolt head, u can then use some stainless wire and tie off the bolt to your frame. then she will never come off.

  • Ruff 400f

Posted June 01, 2007 - 12:56 AM


i once badley cracked the casing around the drain plug on a 93'yz 125. With no money to fix it, i thought yeh Quick steel (a type of putty). I needed it into the hole, without the sump plug, let it set, then continued to crack around for another few years on that bike. Not one sign of a leak, even after bashing on rocks. It was difficult to change the oil but well worth the cheap repair.


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