74 fork oil drain bolt stripped, now what

Discussion in 'Tech Area' started by dehondaguy, Oct 1, 2017.

  1. dehondaguy

    dehondaguy New Member

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    looked but could not find anything , I'm sure I'm not the first one to have this happen, what's the best way to deal with it, its a nice original bike and want to keep repair inconspicuous. thread repair or bigger bolt ?
     
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  3. Deoodles

    Deoodles Active Member

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    How bad are we talking? Can some teflon tape on the bolt work. If it's truly stripped my personal preference would be going to the next size bolt but remember you still have to use a crush washer.
     
  4. racerx

    racerx Administrator
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    This is another one of those repairs that is counter-intuitive...nowhere near as simple as it looks. The drain plug must be exactly straight, not something that can be done by hand. Miss by a tiny fraction of a degree, and you'll have a chronic oil leak to fight. These threads are going to see more action than any others on the bike, no bandaid/kludge repair is going to last long. You'll have to drain the oil & pull the motor to do any kind of thread repair, regardless. Just take it to a machine shop, where a precision repair will be routine work. I'd use a Helicoil. You'll get a solid, undetectable, repair for the <minimal> extra effort of hauling the motor to a pro. Afterward, pull the clutch cover, lean the engine over toward the RH side and hose-out the metal filings with solvent. They'll be trapped in the chamber with the oil screen. The outer clutch cover will be even easier to clean, off of the motor.

    This would be an ideal time to clean the oil spinner, while the clutch cover is off...killing two birds with one stone.
     
  5. Deoodles

    Deoodles Active Member

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    Are we talking the front fork plug or motor oil drain bolt?
     
  6. dehondaguy

    dehondaguy New Member

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    this is the bolt for draining the fork oil, not the crankcase oil, the bolt threads in but doesn't tighten down
     
  7. dehondaguy

    dehondaguy New Member

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    thinking now, these bolts are fairly short, wonder if this hole is threaded deeper than what the bolt is reaching and if going to a longer bolt would catch the threads that are into the casting further, there is a boss that is bumped out from the fork so guessing the bolt could be at least double in length.
     
  8. racerx

    racerx Administrator
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    Apologies, gents...not my day to be the sharpest spoon in the knife drawer.:confused:

    Okay, I'm done with the mental floss so back to the actual topic. You might be able to get by with a longer bolt, or by epoxying the existing bolt. I'd helicoil the thread and be done with it. Unlike the crankcase drain plug, this one is fairly easy for a talented DIYer.
     
  9. scooter

    scooter Well-Known Member

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    The original thread is 6mm x 1.0 mm pitch x 8 mm length. If it were me, I would source a 7mm x 1.0 mm tap if you don't have one and a new 7mm x 1.0 x 8 mm bolt and washer. The clearance drill for a 7mm thread is 6.1 mm or 15/64". With the same thread pitch you might even be able to chase the old threads which should keep your tap straight enough. You'll have to go by feel.
     
  10. dehondaguy

    dehondaguy New Member

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    Just to follow up on this issue, I ordered a 7 mm tap off of fleabay only to find I couldn't source the 7mm bolt locally, went to option 2 and ended up putting a helicoil in it, bought the setup online and it went easy, was worried about the little breakaway tang at the end being hard to retrieve so I ended up just leaving it on, the hole sits low enough in the cylinder that I don't think it will be an issue, about 3.2 oz of ATF doesn't really seem to do much as far as dampening anything though.
     
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  11. racerx

    racerx Administrator
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    Dry-fill, after a teardown & cleaning, requires more like 3.5-3.8oz. Optimal fill level takes a little trial & error testing. 7W oil, including ATF, is too thin to deliver adequate damping. IMHO, 15 or 20W works a lot better and optimal fill level (fork leg fully compressed) will be ~2.5" below the top of the fork leg. As long as the fork internals aren't scored & worn, carefully adjusting oil fill level and selecting the right viscosity can make a HUGE difference.
     

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