Honda GXH 50 QHA or QXA?

Discussion in '4-Stroke Engines' started by Irish John, Jul 14, 2008.

  1. Irish John

    Irish John Guest

    I need to know will the Honda QXA work with a Grubee gearbox & clutch.
    According to Small Engines Warehouse the QXA has a 5/8" dia X 1&1/4" shaft and the QHA has a 5/8" x 1&5/8" shaft. Also the QXA doesn't say if the shaft is keyed.
    Can someone tell me if the QXA will do the job cos the Honda agent in my parts has no listing of the QHA.

    I need to buy it tomorrow at the latest and I want to be sure I'm getting the right thing.

  2. Irish John

    Irish John Guest

    Got a Hoot GB and HS engine kit today from ZBox Australia. It says the shaft is 15.8mm X 33.5mm and is same as the Honda GXH50. I doubt this can be right. The engine tray is fixed length, not adjustable and the bikes it will fit are actually pretty limited. No answers to my query above? I know Fetor said on another posting that both Hondas will fit the Grubee GB but I'm not sure he has one of each and I need to be sure to shell out $500.
  3. ocscully

    ocscully Member

    The shorter of the two shafts you listed works for sure. Myself and several other members here have purchased this engine from Small Engine Warehouse and purchased kits from to mount them in bikes. You can do the conversions as well as I can 5/8th in. = 15.875mm, 1-1/4 in. = 31.75mm I have no experience with the longer Shaft other than having read on these forums that other people say it works as well. If I read the listings at Small Engine Warehouse correctly, you have the designations reversed. The1-1/4 in shaft motor is the QHA and comes without Tank and sells for $210.00 US, The QXA is the 1-5/8 in shaft and comes with the Tank and sells for $260.00 US

  4. Irish John

    Irish John Guest

    Thanks so much Oscully, that was exactly what I wanted to know. Incidentally I think the HS engines that come with the Hoot GB can also take a Grubee or the Hoot can go on a Honda QHA. So the paperwork tells me but I'll know for sure in a few days when I build one.
  5. grezm0nkey

    grezm0nkey Member

    irish, is it possible to get some dimensions from your gxh40 and grubee setup. Im trying to build a felt MP with that setup. just want to make sure it all fits. Im going to pick up my bike frame today and want to look at the frame. get ideas on where to put everything. i read your old posts about you having interest in this felt bike. i attempting an in-frame tank.

    if you have the time some basics on motor Hight x Length x Width, mount tray HxLxW, possibly a pic with measuring tape next to it.

    apologizes for ask so much, Im waiting on a grubee like some others in here. all i can do is wait for restock and do some planning.........dreaming mostly.

    cheers irish

  6. Irish John

    Irish John Guest

    Grez, the dimensions are all on the suppliers websites but the MP will take a Grubee|4-stroke cos her's a picture of one in another Felt with same top tube.
    The problem is getting the chain through the tight gap between tyre & rear seat stay. You'll need to cut away the mudguard for sure but the fat tyres might have to go. Take a 415 chain to the shop & try it. See pics below - apologies to the Felt MBc owner whose pic I borrowed.

    Attached Files:

  7. Irish John

    Irish John Guest

    No shaft key with Honda motor

    I ordered a Honda engine from my local Honda dealership and it came without a length of key for the shaft. Nobody here stocks 4.5 x 4.5mm keys. It's an unusual size. It has an imperial measurement but I forget what it is.
    It's not much fun having to chase up something that should come with the motor itself.
    I've read here that the engine shaft keys are softer metal than the shaft so they are sacraficial but shaft keys are tempered steel and harder than the shaft so this info sounds incorrect. There is probably a sacraficial key on the little flywheel on the other side of the motor.
  8. HoughMade

    HoughMade Guest

    As to the softer issue- I have always assumed they were all supposed to be softer, but like I said, that is an assumption.

    The measurement is 3/16"
  9. Irish John

    Irish John Guest

    I would have assumed that too cos it sounds logical. That picture of someone's Hoot|HS (was it Cruiser 66's?) where the key took off a piece of shaft sort of implies that the key is made of tough stuff.
    Anybody know of a wide one pice crank supplier cos I'm needing some right now? I'll swap 3 piece ones if thet want cos I can't use them.
  10. Irish John

    Irish John Guest

    I sit corrected HoughMade. The keys are tempered steel but not as hard as the shaft. The Honda dealer told me the key was tougher than the shaft but I've come to realise that they aren't that clued up about metallurgical matters (or much else) and today I was talking to a 4th generation toolmaker who told me that the Key was indeed sacraficial because that is it's major purpose. I believe the toolmaker but he also took a look at my leaking fuel tanks I'd brought over and said he could make me identical ones out of aluminium that wouldn't leak. The 4-stroke's vibrations on my suspensionless Schwinn seem to be causing the leaks. The other tanks leaked from being used on similar bikes. I must say that when I put my hand on the tank at 45 km\hr the vibrations are bad. Much worse than at 40 km\hr. I think I might find a solution by using some padding under the tank. I'm going to try grinding around the leak, sanding and soldering to see if I can fix them.