Oil drain bolt threads messed up

6 replies to this topic
  • stevaroni

Posted October 19, 2012 - 05:21 PM


I just got a 2004 WR 450. First on my todo list was to change the oil. When I removed the lower bolt on the oil filter cover I noticed there was no o-ring like the manual said should be there. Since no oil came out of the hole, I replaced the bolt, but it would not tighten up. Upon removal I could see that the threads were stripped out. Can this be retapped to a larger bolt size, or do I need to replace the case? If it can be retapped, how do I keep the metal filings from getting into the oil system?

Also, if the manual says to remove this bolt as part of the oil removal process, why did no oil come out?

  • kawi380

Posted October 19, 2012 - 05:28 PM


First of all, you should be able to overdrill the whole and install a helicoil...though I am not sure about where the filings are going to go :excuseme: You may need to just change the oil a few times to make sure you get everything out...

Also, if you have not had the bike running just prior to changing, the oil may have founds it's was back down to the bottom of the bike. You should always warm up your scoot before changing the oil to get it warm and thin so it runs out quicker and easier :prof: .

  • MANIAC998

Posted October 19, 2012 - 05:59 PM


Yeah, the manual says oil will come out, but hardly any ever does. It's just Lawyer speak. Anyhow, you should be able to Heli-coil it. I wouldn't drill it out and oversize it, just heli-coil it, and you should be fine.

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  • rknaub

Posted October 19, 2012 - 08:32 PM


I had the threads stripped on my yz 426, I posted about it in the yz forum. I used a time sert, worked great, but a heli coil is easier... Time sert can be installed with the motor together, Helicoil requires you to remove the install tang, which is easier done when you split the case. Overall, it's a easy fix. I didn't like the Helicoil for several reasons, the insert was too short was my biggest turn off, also, it doesn't seal off the cross drilled drain hole, which is the cause of the whole problem. Check out the yz forum for lots of info on this.

  • stevaroni

Posted October 20, 2012 - 11:48 AM


It would seem that splitting the case would be best. From posts I found on the YZ forum, the cross-bore into the oil filter bore also extends down into the case. So drill filings would be deposited directly into the case. Any comments?

Also, I'm probably missing something obvious, but if you have to over drill and then tap the bore in order to use the Heli-coil, why not just use a bigger bolt after the over drill and tap and avoid the expense of the Heli-coil?

  • MANIAC998

Posted October 20, 2012 - 05:30 PM


The something obvious that your probably missing is the bolt. If you can find one that is a perfect match but larger, than do whatever you want. Most people like to keep the fasteners all stock. Good luck.

Oh yeah! And the Heli-coil is a stainless thread repair, so the chances of ever having the problem again are almost nill.

Edited by MANIAC998, October 20, 2012 - 05:31 PM.

  • stevaroni

Posted October 20, 2012 - 07:55 PM


Thanks all for the replies--it was very helpful in knowing what to do.


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