350 Loose case bolt. Do I really need to pull the engine?
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  1. #1
    Senior Member MotoPsycho's Avatar
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    350 Loose case bolt. Do I really need to pull the engine?

    My '71 350 has developed an oil leak. It's been getting worse, so I finally took the time to look into it last night. Turns out that the case bolt on the far front, LH side of the engine has come loose.

    The good news is that the source of the oil leak and the way to fix it is obvious. And, since that bolt sits right in the frame, I didn't lose the bolt.

    But that's also the very bad news. I can't see anyway to access that bolt without pulling the engine.

    At a minimum, it looks like I'm going to have to pull the tank and the carbs. Take off the chain. take off the exhaust. Take out all the mount bolts. And then I can hopefully move the engine enough to get at that bolt.

    Or, I can just park over some kitty litter and keep an eye on the oil level.

    Any suggestions?
    Attached Thumbnails Attached Thumbnails 350 Loose case bolt. Do I really need to pull the engine?-casebolt.jpg  

  2. #2
    Senior Member Brown Bomber's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    Need input from someone that knows the 350 better than I, but it looks like one of the bolts that go into the crank shaft bearing holder. I wouldn't run the engine until I found out.
    Keep the shiny side up.
    Allen Blankenship
    1976 CB500T (Witch's Promise)
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    1973 CL450 (project)

  3. #3
    Senior Member MotoPsycho's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    yeah, I think you're right.

    That bolt appears to do more than simply hold an oil pan on.

    Whelp, time to start dismantling!

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  5. #4
    Senior Member MotoPsycho's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    Oh, I know that letting leak really isn't an option. Especially since that bolt does hold the crank bearings in place.

    I looked at it a little closer over lunch. If I can get the bolt turning and threaded back up into the engine, I can get a wrench on it to torque it good and tight. I can barely touch the bolt with one finger as it is, so I don't know if that'll happen or not.

    I'll give it a good try tonight and let you guys know what I come up with.

    What's really killing me is that I know I need to address some issues in the tranny. If I go so far as to pull the engine, I'd be silly not to split the crankcase and fix up the bottom end.

    Hopefully I won't have to resort to dropping the engine, though.

  6. #5
    Senior Member MotoPsycho's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    Well, I managed to get the case bolt tightened. At least for now. I was able to thread the bolt back up against the case with a flat bladed screwdriver. Once it was up there, there was just enough room to give me hope that I could tighten it with an open ended wrench. But, not enough room to actually do it!

    So, with some judicious use of the ole bench grinder, I was able to "reconfigure" a 12mm wrench to do the job for me. It felt like the bolt was tight, but I don't know how much the weakened steel of the wrench was flexing.

    No oil leaking for the last 3 days, but I'll be keeping a real close eye on that bolt for awhile.

  7. #6
    Super Moderator frogman79's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    Some times the best tool is one that is MADE for the job.
    Franz >>> 450 build >>>360 Build

  8. #7
    Senior Member MotoPsycho's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    My only regret is the 12mm wrench is an elusive one. I've got a half dozen 1/2" wrenches - but I'll be hard pressed to find another 12mm when I need it again. I really need to organize my tool boxes better!

    But yeah, 5 mins on the bench grinder beat the heck out of a 4 hour engine removal and replacement!

    She really is a finicky beast. Hopefully she'll hold together until late fall. But then I should have all the bugs worked out or identified. Then, this winter she's getting a full engine rebuild. I'll probably tear her right down to the frame and get her looking a little prettier too.

  9. #8
    Super Moderator nigelrharris03's Avatar
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    Re: 350 Loose case bolt. Do I really need to pull the engine

    That 0.5mm makes all the difference between friends
    Nige

    CB450K0 Bomber 1967
    CB650Z 1978

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