Looking to replace a Hoot (?) gearbox...recommendations?

Discussion in 'Transmission / Drivetrain' started by salfter, Feb 26, 2014.

  1. salfter

    salfter New Member

    Long time, no post...life got in the way. Back in 2007, I picked up a 4-stroke kit from someone who was selling them on eBay. Pre-install pix of the bike that received it and some post-install closeups are over in this thread. It's a 49cc Huasheng 4-stroke with what I think has come to be known as a Hoot gearbox.

    The original gearbox used straight-cut teeth on the gears. It lasted maybe 200-250 miles before it ground itself into junk. After a few months sitting idle, I found a bolt-up replacement for it from another eBay seller, this time with helical-cut gears. On the first ride, it did seem quieter...sounds good, right? On the other hand, the small gear on the clutch was welded on with three tack welds. On a trip across town, the welds broke. :rolleyes7: I left it with friends until I could get a truck over to haul it home.

    It then sat in my garage for the next few years as life got in the way: started dating, found a girl, married her, learned that she had stage 4 cancer, helped out as best as I could through surgery, chemo, and other related nastiness...but it was too much for her and she passed a few months ago. :sweatdrop:

    Now I have no excuse for not getting this thing running again. It needs a new gas tank as I had left it with fuel in the tank, and the 10% ethanol in it went to town on it...no problem, I've found several sources for a replacement. I've yanked the carburetor and cleaned it out, so that should be good to go. I also found someone at work who has a welder, so I figured I'd let him try welding the gear back onto the clutch. If it works, great; if not, I would've been in the market for yet another gearbox anyway.

    The gearbox is put back together, and I think it'll work...for a while, at least. From what I've read of the posts that have been made in my extended absence, it would appear that what I have is the bottom of the barrel. A couple of belt-drive transmissions have turned up in the meantime, one from Grubee and another from EZ Motorbikes. If I end up replacing the gearbox I have now, which of these is least likely to cause trouble in the future? Which one would be the easiest to bolt up? Has anyone done this changeover, and if so, how did it go and where did you get your parts?

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    The EZ Motorbike and Grubee 4G T belt are good transmissions.

    Also check out the transmission from Affordable Go Karts.
  3. Barry

    Barry Member

    That affordable go carts setup interests me. I wonder if it would mate to a shift kit?
  4. salfter

    salfter New Member

    I've managed to confirm that what I have is the Hoot gearbox. In fact, I'm 99% positive it was part of this kit:


    I measured the crankshaft, and while it appears to be the same length as standard, it appears to have been turned down to 15 mm diameter. It still has a slot for a key in it. The engine description at the link says "Gear box fits Huasheng F142-1 with 15mm dia. shaft."

    I'm leaning toward either the Affordable Go Karts or EZ Motorbikes designs, as they have some drive reduction (by chain or belt) before the clutch. The 50-tooth wheel sprocket might be slightly less optimal for either of them, but that can be changed if it's absolutely required. A 5/8" input sprocket/pulley isn't going to work too well on a 15mm crankshaft. Is either of these available to fit on a 15mm shaft, either directly or possibly with an adapter? (By my math, a shim 17 mils thick that wraps most of the way around the crankshaft would bring it up to 5/8". Going by this page, 27 ga. sheet steel would bring the diameter up to a bit over 0.623", which is pretty close to 5/8".)
  5. IbedaYank

    IbedaYank Member

    better off posting pictures of engine with the hoot taken off as there is 2 versions of the hs motor made one uses the weedeater style clutch the other uses gokart style
  6. salfter

    salfter New Member

    Here's the engine, with some measurements:


    The clutch rotor is visible in this photo of the disassembled gearbox before I chucked it in the trash:

  7. IbedaYank

    IbedaYank Member


    here is what the tapered shaft motors look like
    I would contact EZM or AGK and make sure that it would fit before buying
    the 4G trans that gasbike/kings sells will not fit as are made for the tapered shaft motors