Odd Little Oil Leak

Discussion in 'General VFR Discussions' started by Bat-1, Nov 20, 2018.

  1. FJ12rydertoo

    FJ12rydertoo Member

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    No offense, but overtorquing a bolt isn't going to do that. Not unless the housing is at an angle. Overtorquing will result in pulled/stripped
    threads, not a bent bolt. You will strip the threads out of the soft aluminum long before that steel bolt will deform like that. I would imagine
    the torque setting for that bolt is about 14lb.ft. The threads will strip out at probably around 20lb. ft.
     
  2. Bat-1

    Bat-1 New Member

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    I can't be sure but going by the empirical evidence I can't see why else the bolts would be deformed. Nothing was on crooked and the threads are not stripped.

    They were on stupidly tight along with everything else the PO touched (I had to use an impact to loosen the bolt on the rear hub for chain adjustment).

    These long bolts go through a long channel that's slightly larger than the bolt (of course) before reaching the threads. I'm sure there's engineering math to determine the weakest link in this chain, though one factor would be how much thread there is. I'm thinking the bolts are the weak link.

    The only clutch cover bolt not warped was the shortest one that's all thread (there are four different sizes).
     
  3. Doug7200

    Doug7200 New Member

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    To add an interesting bit of info regarding engine bolts on Japanese motorcycles:

    If one is unsure which bolts goes where on an engine case, as they vary in length, there is an easy way to to sort which hole they go into.

    Place the part - cover, etc., in place, then drop the bolts into the hole where you think they go. Once this is done, check to see if the heads of the bolts are all equal distance from the bolt contact surface - they should all stick out the same distance. If not, move bolts around until they do. Easy and correct every time.

    This was given to me by Honda USA head of technical training many years ago.

    Glad you found and fixed the leak.
     
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  4. FJ12rydertoo

    FJ12rydertoo Member

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    About the only thing that will cause bolts to bend like that is to put sideways force on them. Like maybe when whatever happened
    that caused that countershaft sprocket to break. Straight line overtorquing simply won't do it.
     
  5. NorcalBoy

    NorcalBoy Member

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    It looks like it may have thrown the chain and locked up at some point. You don't get that kind of tweakage from over torquing. The threads in the case would have stripped out, before you could possibly do that to the bolt. Whatever it was, my guess is that was why it was up for sale in the first place.
     
  6. Terry Smith

    Terry Smith Member

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    I'm sure you're right about this Doug, but wish I had worked it out before on my ST1100 engine when I changed the water pump. I found out the hard way that a 30mm long bolt does not fit where a 25mm should be, although it nearly does, until you give it just a touch more torque and the bolt snaps. In this case the threads in the aluminium engine block were tougher than the steel bolt.
     
  7. FJ12rydertoo

    FJ12rydertoo Member

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    Yeah, some of those little bolts can be broken by overtightening, but not bent like those you posted. Heaven
    knows I've broken a few. :)
     
  8. Bat-1

    Bat-1 New Member

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    Ultimately we'll never know. But if it had thrown the chain there'd be ample evidence of that on the change cover, but there's barely a scratch on it. And it's soft aluminum. I seemed to be marring it with a plastic scraper while getting the old paper gasket off.

    I think he sold the bike for the reason the vast majority of people do -- he wasn't riding it and his interests/group of friends had changed.

    There seems to be this believe that there's a vast pool of people just lurking to unload some broken down PoS on the unwary. I buy half a dozen or so bikes a year (at least for the past couple years) and that has not been my experience. People generally love their bikes and treat them with great care. They have a lot invested in them, both emotionally and $$$ wise.

    The PO on this bike didn't seem like the brightest bulb in the chandelier but not so dim that he'd sell his VFR cheap because it needed $5 worth of bolts and a $25 sprocket.

    Don't know if running with one missing tooth has been detrimental to the chain. There's nothing visible on the rollers and it's not measurably stretched so I'm leaving it for now.

    She's been on the sidestand for 24 hours now with no drip. I won't call it a successful fix until I've driven her a couple times and everything proves tight but signs are good.
     
  9. FJ12rydertoo

    FJ12rydertoo Member

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    My initial thought is that the change cover broke when whatever happened occurred. The PO replaced the cover with
    a used one but reused the old bolts.
     
    Last edited: Dec 3, 2018
    fink, PetePower and Terry Smith like this.
  10. NorcalBoy

    NorcalBoy Member

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    Merely an observation and thinking out loud. I hope you have solved your oil drip issue, that's really the main thing. Best of luck.
     
  11. Bat-1

    Bat-1 New Member

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    Time to put this thread to bed.

    The leak was the change cover and swapping it out along with a new gasket seems to have cured the oil leak. Not a drop in over a week on the sidestand.

    A fairly easy job. The hardest part was removing the old paper gasket. Not counting that if I had to do this again it would take about 1.5 hours. Took about twice that the first time as I'm old and, umm, careful (not slow).

    I think when the PO replaced the front sprocket he slightly warped the change cover during re-installation of the clutch-slave/sprocket cover. Three long bolts go through the clutch slave, the guide plate and through the change cover. I noticed during reassembly that you have to be very careful with these long bolts because if all the elements aren't exactly aligned it's easy to go in at a slight angle.

    The bolts are presumably steel but it doesn't take much to warp them. One of my new ones got a little unstraight before I backed it out and made sure everything was perfectly aligned.

    The new sprocket is a 16 tooth JT brand. Here's what it looks like vs. the old PBI 15 toother.

    Now my speedo should be "healed" I hope.

    [​IMG]
     
  12. Big_Jim59

    Big_Jim59 Insider

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    I replaced the old 15 tooth sprocket with the 16 tooth one. My speedo still reads low. I run 80 indicated for a true 71 mph.
     
  13. FJ12rydertoo

    FJ12rydertoo Member

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    That sounds about right: 8%-10% high is pretty normal. A cheap bicycle computer will clear up the confusion for a few bucks.

    [​IMG]
     
  14. NorcalBoy

    NorcalBoy Member

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    As long as you are capable of reading a basic metric ruler or caliper, the online parts fiche clearly indicates which bolts go where....of course, that would be way too easy. That is why I don't trust any dealer to work on my machines, that explanation raises the hair up on the back of my neck.
     
  15. ridervfr

    ridervfr Member

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    "Place the part - cover, etc., in place, then drop the bolts into the hole where you think they go. Once this is done, check to see if the heads of the bolts are all equal distance from the bolt contact surface - they should all stick out the same distance. If not, move bolts around until they do. Easy and correct every time."

    was trying to do the "text quote" button but could'nt find it. Yeh, I been doing that forever. Never really thought about it, works on every bike, bmw I used to used cardboard and stick the bolts in the corresponding holes to the cover so any F up would be mitigated :mech: Peace out.
     
  16. Doug7200

    Doug7200 New Member

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    Why would this simple method raise hairs? The engineers design the bikes, parts and bolts to work this way!
     
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