HONDA GX 25 Info

Discussion in 'Friction Drive' started by JGH122, Jun 4, 2016.

  1. JGH122

    JGH122 Member

    GX25_(Type_SAT).gif There is a version of the HONDA GX 25 usually found on small pumps that does not have the bell clutch.
    You can get the fan shroud and clutch assembly to convert it for friction drive systems here. (go to page F) on the right you will see the pump housing and shaft. On the left you will see all the clutch parts you need.

    It costs around $50 to convert the engine.
    Last edited: Jun 4, 2016

  2. HeadSmess

    HeadSmess Well-Known Member

    thats pretty cool actually... replace the pump shaft with something a tad longer, dont bolt it to the flywheel, rather drill its holes out large enough to slip over the bolts themselves, so they act as drive pins (if its dead rigid it can cause issues, like a broken crankshaft, i found), then add an extra outer bearing to the housing using three of its four bolt holes, get the old 5/8 (or was it 1/2"?) star washers as a roller, nut on the end to clamp the whole lot up tight, and you got an easily serviced, virtually bulletproof FD setup.

    i havent done an FD setup in like, a decade? but i did find (external) star washers made the BEST rollers around. easily replaced, hardened steel, cheap, etc etc , yarda yarda, rhubarb rhubarb... attaching the engine was the hard part.
  3. libranskeptic

    libranskeptic Member

    If i understand u, u propose a friction roller shaft mde of a threaded bolt with scads of star washerscinched tight with a nut.

    If so, .5" star washers seem small. My 2 stroke brushcutter friction roller on a 26" was 1"~, and seemed about right.
  4. HeadSmess

    HeadSmess Well-Known Member

    1/2" is the ID, the shaft they ride on.

    they end up at about 7/8" on the OD from memory. obviously you need external star washers.

    the tyre size makes no difference with FD.

    for hills, and plain usability/no slip, i found just under 1" to be ideal.

    any bigger and you just shred tyres as it slips too much.

    but yes, you got the idea.
    libranskeptic likes this.
  5. JGH122

    JGH122 Member

    GX25 shaft.jpg There is a scad of options for these engines.
    You can buy a housing with a 1/2 or 5/8 shaft
    or even this setup
    I just bought a GX25 that was on a pump and it is the sweetest little motor I have ever had.
    I picked it up from a guy who used it 3 hours and forgot to drain the pump.
    Pump housing cracked when it froze.
    He gave it to me for $40.
    Last edited: Jun 11, 2016
  6. HeadSmess

    HeadSmess Well-Known Member

    i love my honda brushcutter... with the right head on it, i can cut down 3" saplings, run it all day, and not have sore hands, ears or yeah...anything. doesnt need to be revved flat out like a 2 stroker, doesnt need premix, doesnt smell...

    you do have to be fairly religious with oil changes, with the tiny little amount they have, it does get "old" pretty quick... pffft, 80ml of oil, so what?

    and dont leave them hanging up out in the rain, it destroys the clutch bearings at the top of the shaft. one day i might fix that... :D
  7. libranskeptic

    libranskeptic Member

    NB, it has an anyway up carby - a boon on a bike