Oil Filter Cap Threaded

Discussion in 'Technical Discussions' started by Tommy020, Jul 5, 2017.

  1. So today I loosened the bolts of my oil filter cap on my wr125x for an oil (filter) change, as I turned the bolts I heard the top left one snap, half the bolt stayed in the thread while the other half of the bolt came out. The other two came out fine (I thought...), turns out the left bottom bolt had ruined the internal threading, so this bolt did come out, and i can put it in again, only it will not tighten.. (when turned in all the way it keeps loosening up). The bottom right bolt (the long one) is fine, no damage or anything.

    So now when I start up the bike the oil comes pouring out under the oil filter cap (as the cap cannot be completely sealed against the clutch cover of the engine. Could someone give me a tip on what to do now? I have a car garage 20 meters up my street, he told me he could drill out the piece of remaining bolt in the thread, and fix both threads with heli-coil. This wasn't risk free though he stated, he said he had about a 70% chance of succeeding. May it be smarter just to purchase a whole new clutch cover for the engine? I saw them on ebay for like 15 dollars. Is replacing the clutch cover a guaranteed fix? As i assume the threading is only in the clutch cover, not deeper into the engine.. (sounds vague.. hope u understand what I'm saying..) any help would be hugely appreciated. New user here btw :)
  2. Blazer

    Blazer Member

    Hi Tommy, the threads are in the crankcase not the cover, so the only options are either to heli coil it or replace the crankcases which will be a big job to fit. It may end up costing more than a decent secondhand engine, if you get a mechanic to replace the crankcases. Best to take a gamble on the heli coil route first. I managed to damage the rubber seal around the inside of the filter cover once and had problems with leaking oil, so it maybe worth checking if the seal on your bike is in good condition and seated correctly.

  3. Hey Blazer thanks a lot for the info.

    However, are you sure that the threading continues into the actual engine, and is not simply just in the cover? I would want to make some pics for clarification but all the pics are too large of a file. It looks like only the long bolt of the oil filter case threads into the actual engine, looks like the other 2 only thread into the engine case cover. Is buying and fitting a new cover really such a hassle? A reply would be greatly appreciated.
  4. Blazer

    Blazer Member

    Yes you are correct, i am wrong :oops: sorry!. The two inner bolts just screw into the cover, so like you say just changing the cover will sort it. :)
    Last edited: Jul 9, 2017

  5. Great, was getting a bit nervous even thinking about having to take apart the whole engine...

    So taking off the clutch cover/crankcase cover is simply a matter of draining the oil and loosening all the bolts on 'edge' of the cover and taking it off, right? Or are there other things I should keep in mind?
  6. Blazer

    Blazer Member

    You don't have to drain the oil if you don't want to, you can lean the bike over far enough so that the oil won't run out, and like you say it's just a case of removing the bolts that hold the clutch cover on and lifting it off. You will find that the rear brake pedal will be in the way a little but you should be able to remove the cover without removing the pedal. A couple of things to be careful of are loosing the two locating dowels arrowed in the attached photo, and damaging the small rubber seal on the inside of the cover when you re-fit it. As long as the gasket isn't damaged it is ok to just pop the cover back on.
    Last edited: Jul 9, 2017

  7. Awesome, thanks so much for your help!

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