Solution for Grubee engager cable bolt breaking

Discussion in '4-Stroke Engines' started by Irish John, Oct 19, 2008.

  1. Irish John

    Irish John Guest

    It's quite easy to snap the cable engager bolt on the Grubee gearbox cos it is hollow and if you tighten the nut up hard the bolt can shear easily. Can't get spares from my Aussie supplier so I fabricated a 6mm bolt and it works better than the original and is more robust.
    I used a 6mm bolt of the right length and drilled a small hole straight through the shaft so the cable fits through. The only thing you need to take care with is positioning the hole just outside the nut so the final locknut can tighten against it. The following pictures should explain the method. Simple but very effective and it wont snap off easily like the old one.
    Incidentally the picture shows a recent kit engager bolt and the screw is so long it catches on the air filter box and interferes with its operation so that if I hadn't broken it by tightening it it would have broken during operation anyway so this method should solve this problem and keep you mobile.
    I used a drill press to drill the bolt but it would have been possible with a hand held drill.
    Normal Engager Cable Bolt.jpg

    The Gear Engager cable Screw Assembly.jpg

    Home Made Engager Cable Bolt.jpg
     

  2. HoughMade

    HoughMade Guest

    Good idea. I broke mine too, but it still works. Seems like that hollow bolt is aluminum.
     
  3. Ghost0

    Ghost0 Guest

    So to you two experts I was reading my manual today for the Grubee gear box, is it correct that you pull the "clutch" lever in to engage the drive and release the "clutch" lever to disengage it?
     
  4. jimraysr

    jimraysr Member

    Pull to engage, release to disengage

    That is the way it works.

    To answer a couple of other questions.

    The engagers (sprag part of it that is, the part that drives one way but not the other) allows you to peddle without the drag of the gears in the box.

    Second it allows the drive sprocket to kick out if the gears jam or the clutch freezes and or the engine suddenly stops. Otherwise the rider would keep going as the bike came to a sudden halt.

    I guess some of the GruBee staff want the engager removed, but Don insists it be left in the design. Seems like a safety device to me. It just needs to be stronger and locked togather in a fool proof manner.

    Jim
     
  5. Irish John

    Irish John Guest

    Yes Ghost that is correct unless you adopt the HoughMade technique where he has managed to reverse the concept so it is like a normal motorbike clutch.
    Pull in to release and let out to engage. His method probably means he doesn't pull the engager on when his revs are too high which shears the drive sprocket key. I think he leaves his engaged most of the time. There is a thread describing his method with pics under the four stoke section - type clutch reversal into the search tool and you'll find it.
    My latest Billinudgel Bullet has a whining gearbox and the gear engager is forever staying in the locked on position. I can fix the latter by disassembling and filing the key\keyway so it slides more easily but it's a big messy job taking the shaft out. The whining gearbox I can't fix - it's just a noisy gearbox and I'm wondering if one of the bearings is kaput cos it's not the shaft-end bolt head rubbing against the casing which sometimes happens. I can only check the sealed bearings by turning my finger in them. Don't think they'd be kaput on a brand new gearbox but you never know.
     
  6. HoughMade

    HoughMade Guest

    Yep, I did reverse it so it was always engaged. There is a post about that here somewhere.

    However, since then, I realized that after I reversed the operation, I never touched the handle, so I disconnected it altogether, but I left it reversed and mounted a small wire pull at the box in case i needed to disengage it in an emergency to pedal (THE HORROR!!!!!) home.
     
  7. Ghost0

    Ghost0 Guest

    Thanks for the input guys. I think with the shift kit a lot of these "safety" things will go away since the freewheel on the rear hub will still function normally so no rear wheel lock problems. With that said I was thinking of ordering the locked 10 tooth output sprocket and getting rid of the 11 tooth freewheel. It seems those are an area of concern as well.
     
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