Newby Screwed up !

Discussion in 'Tech Area' started by Beretta, Jun 8, 2020.

  1. Beretta

    Beretta Member

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    Reinstalled the Flywheel today and used my Air Impact Wrench- Big Mistake I know--Broke off the Snout- Luck IMG_4325.jpg IMG_4324.jpg y Me I Live in Race City with the Best Fabricators and Welder's in the Country. My Buddy comes over to take a look and Say's - No Sweat !
    Repairing In the Am!
     
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  3. mark from florida

    mark from florida Active Member

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    lookin at that I I would think new crank? hope the weld job works for you.
     
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  4. racerx

    racerx Administrator
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    What mark from florida said. Bucket of popcorn at the ready...
     
  5. kirrbby

    kirrbby Well-Known Member

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    I know a guy who would make a weld like that, and do it well. Logic says, it really only has to be strong enough to keep the flywheel tight. But, I wouldn't use a impact gun to tighten it again :) I would be a bit nervous when I needed to loosen it too.
     
  6. Gary

    Gary Well-Known Member

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    Nut does not hold it on anyway- it's the taper that does the work. Think about it a bit,if it did why would you need a puller to remove a flywheel. Will have to see what kind of weld you end up with.If that looks good then it might be a good idea to get some valve grinding paste and lap the flywheel to the shaft as well. At this point you have nothing to lose but a new crank is the best option. Good luck
     
  7. Beretta

    Beretta Member

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    I'll let you Guys know -Gonna do this on Thursday,
     
  8. racerx

    racerx Administrator
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    A very valid point. However, it's the hex nut driving a tight enough interference fit to lock the crank to the flywheel bore. Theaded fasteners can easily generate huge clamping forces...and for every action there is an equal & opposite reaction. In this case, it's the amount of force "pushing back" against the hex nut and threaded end of the crankshaft...with, potentially, one additional vector. If the hex nut does not seat evenly against the face of the flywheel hub, the end of the crank will be deflected, under a huge psi loading, and that may break the threaded end; it could be sufficient to snap the end off of an intact crankshaft.

    The #1 reason why used crankshafts end up as scrap metal is damage to the flywheel end. The number of otherwise rebuildable cranks I've seen with damage to the clutch side...I could count on one hand. IOW, this is a difficult repair...
     
  9. Gary

    Gary Well-Known Member

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    Oh I agree just throwing it out there,he has absolutely nothing to loose. Many don't realize why the taper is there,key does not hold it either it's there to locate the points cam. I thought I remember someone here along time ago drilling and tapping the crank end for a bolt.....
    Aren't 3 speed cranks not available?
     
  10. allenp42

    allenp42 Well-Known Member

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    Same here. I have seem a few cranks that had been drilled and tapped. The 3 speed crank is NLA but do show up from time to time. CMSNL has one for for a tidy sum of ~$301 + shipping.
     
  11. racerx

    racerx Administrator
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    It's a matter of the price tag. 6v/3-speed cranks are not rare, Z50 & CT70 cranks made prior to 1982 are all the same. That left us with a huge pool of used specimens and most of them can be rebuilt, if the rod is worn. But new 6v/3-speedcrank assemblies are NOS-only. That has tilted the playing field. A shop will typically charge around a buck seventy five to rebuild a crank. Add-in the price of a rebuild kit plus postage and the cost gap narrows considerably. If you have to source a rebuildable crank, in addition to that...well...it's easy to see why the market will bear the current price of NOS.
     
  12. OLD CT

    OLD CT Well-Known Member

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    I am almost certain I have a perfectly good used 3 speed crank I saved after installing a stroker crank. The flywheel needs to be properly torqued to 25 ft lbs. You know what happens when you over torque one, if you under torque, it will sheer the flywheel keyway.
     
  13. Beretta

    Beretta Member

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    For Sale ?
     
  14. Beretta

    Beretta Member

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    Crankshaft Complete and Perfect!
    Centering the Broken pc took some time-Splot weld-Spin eng and tap -spot weld- same process several times until were happy that it was as true as we could get it---then welded 360 degrees- Chased the Treads- Used a little thicker washer- Torqued to 25 ft lbs.
     

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  15. racerx

    racerx Administrator
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    I like this! Your buddy is one seriously talented welder.(y)
     
  16. airblazer

    airblazer Active Member

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  17. allenp42

    allenp42 Well-Known Member

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    Wow. This is impressive! By looking at the weld and not seeing any splatter, did he TIG weld it?
     
  18. Beretta

    Beretta Member

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    Tig - set very low - very soft steel -
    50 to 60 amps .
    Just took it for a 2 mile ride - good so far
     
  19. Tripod

    Tripod Active Member

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    I need a steering stop welded on. Does he make house calls?:D

    Nice work.
     
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  20. Beretta

    Beretta Member

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    After we finished we talked about alternative solutions for these broken off Cranks- He says no sweat- He can just weld a mm Bolt directly to the shaft- cutting the correct Length of course.
    So don't throw away those Crankshafts --They can be saved !
     
  21. scooter

    scooter Well-Known Member

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