Clutch bucking bar diameter? make my own bucking bar?

Discussion in 'Transmission / Drivetrain' started by jatgm1, Apr 28, 2016.

  1. jatgm1

    jatgm1 Member

    what is the diameter of the bucking bar? and if i were to go to home depot, what kind of metal rod can i buy, then cut into pieces and grind to replace the bucking bar? i mean, its like 5$ for a 1 inch piece of metal on ebay, how the hell to those numbers add up?
     

  2. crassius

    crassius Well-Known Member

    it's 8mm, but 5/16 would be ok if you use hardened steel & polish the ends well
     
  3. jatgm1

    jatgm1 Member

    8mm hardened steel rod? what would be the cheapest way to cut it? and polish it? im an apartment mechanic so, you know, limited tools. could i get some sorta hack saw and sandpaper? and if so what kind would be recommended?
     
  4. butre

    butre Well-Known Member

    hacksaw would be a pain in the ass, know anyone with an angle grinder? or even a dremel would work

    you could go at it with bolt cutters and sand down the burr made by those.
     
  5. jatgm1

    jatgm1 Member

    might be a better idea overall to just try and get a cheap angle grinder.. the bolt cutter idea could work though. is there a particular type of sandpaper that would work best? sorry for the dumb questions but this 2 stoke kit is how im learning about engines and whatnot.
     
  6. butre

    butre Well-Known Member

    just cloth backed and around 240 grit

    harbor freight has a passable angle grinder for about $20
     
  7. 45u

    45u Active Member

    You do understand these need to be hard! Mild steel is not going to work.
     
  8. crassius

    crassius Well-Known Member

    I'd either order one or look for someone nearby with a dead motor for parts - what happened to your old one?
     
  9. Timbone

    Timbone Active Member

    I've been thinking on this bucking bar thing. First, the length I see repeated is 28mm. At the very least, stainless steel. Perhaps the shoulder off a longer bolt. Grade 5, 5/16". Or Grade 8 - I use Grade 8 whenever possible. You could also use the base end of a hardened 5/16" drill bit.

    The clutch on these HT motors is pretty simple and dependable. The only weak spot iOS the bucking bar / cam interface. You have to have a clutch cam in reserve ready to go at all times.

    Ideally, I'd envision a kind of hydraulic activator that would simply push the bucking bar in to disengage the clutch. It would have to be small and dependable.

    Just me thinking out loud.
     
  10. HeadSmess

    HeadSmess Well-Known Member

    mild steel is ok if you dont mind keeping an eye on it and replacing every few weeks. grease helps. as does the lone ball bearing, also 8mm. can get them in ceramic too, no idea why though :)

    me myself, having lots of HSS and carbide endmills, use one of them.

    if youre willing to find a local machinist, and ask them for an old broken 8mm or 5/16 endmill...they will be only too happy to give you one. what else will they do with the things? can buy them new on ebay for a few dollars. the machine shop will probably be just as happy to cut and grind it down to length. takes all of 5 minutes with the right tools, ie, angle or bench grinder... it doesnt even have to be an exact length... a mm or two doesnt make much difference either way.

    endmills or slot drills. NOT plain old twist drills, they have soft shanks. endmills are solid HSS.
     
  11. skyash

    skyash Active Member

    This bike has a different bottom end and the bucking bar is longer the only one I have ever found
     

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  12. crassius

    crassius Well-Known Member

    I have a lot of them here, they vary in length by about 3/8in.
     
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