honda gxh50 with centrifuegal clutch

Discussion in '4-Stroke Engines' started by cspaur13, Apr 29, 2009.

  1. cspaur13

    cspaur13 Member

    im really wanting to buy the honda but i dont really care to have the grubee gearbox and its very expensinve. is it possible to get a centrifuegal clutch with sprocket attached and put a chain on it and run it to the sprocket or would that not work. ive seen like on small engine warehouse they have the clutch with the sprocket attached and it fits for the motors on there sites so you can put the engine on go carts and minibikes. if i did this would i just get small speeds or normal 35mph like with the grubee
    any help please.
    thanks,
    cody


    like this one its 5/8 just like the honda shaft. will this work.
    http://www.smallenginewarehouse.com/product.asp?PN=CLUTCH-35-58&desc=Max-Torque Go-Kart Parts Clutch 5/8" Hole#35 Chain for Mini-Bike, Go-Cart, 11 Teeth
     
    Last edited: Apr 29, 2009

  2. HoughMade

    HoughMade Guest

    Your need the reduction of the gearbox. It provides 3.7:1 reduction. Without a gearbox or jackshaft of some sort, you'll have to find a somethink like a 170 tooth sprocket to go with and engine sprocket of 10 teeth...I think that's bigger than the wheel itself. The GXH50 runs at twice the speed of a larger small engine and go-carts and mini-bikes have tiny wheels. makes a big difference in the reduction required.
     
  3. ocscully

    ocscully Member

    The Honda GXH50 and the clone (the Hueseng) are a bit different than the normal 4-stroke motors. First they have a Maximum rpm of 7800rpm vs the 3600rpm of others and second they Idle at 1800rpm-2000rpm. What this means is you need a clutch that is set-up specifically for the rpm range of these motors. The clutch you have linked to from small engine warehouse is not made for the Honda. Max-Torque can make you a clutch that will work in the rpm range of the Honda but it costs closer to $100.00.

    The other problem you run into with the setup you describe with the clutch on the output shaft of the motor and a driven sprocket on the rear wheel is you can't get the amount of total reduction necessary. The gearboxs that come with the various 4-stroke kits are providing a primary reduction of 3.7:1
    (grubee gearbox) when you eliminate the gearbox you have to make up the reduction with a larger driven sprocket at the rear wheel. Say with a 10t driver on your clutch you would need a driven sprocket at the rear wheel of 190t+-

    You can eliminate the gearbox buy adding a Jackshaft to your bike. You might want to spend some time searching this site for threads on Jackshafts and alternative drive trains to hep you understand all of this. One thig to be aware of is the costs of putting together a custom/alternative drivetrain can get quite high. There is a New Kit just now starting to become available called the EZ Motorbike Silent drive. Early indications are that it has solved pretty much all of the problems that folks are having with the Chinese Gearboxes. It costs more than the other kits but if it is as reliable as the early reports indicate it will be worth its extra cost in my opinion.

    good luck with your research,

    ocscully
     
  4. cspaur13

    cspaur13 Member

    thanks for the help. wait what would happen if i just ran the 10 or 11 tooth sprocket with just my 44 tooth on the back. would there be no speed or 2 much. i dont really get what will happen with out the reduction.

    HoughMade
    u have a honda on ur bike right. i thought i saw something about it in 1 thread but that was ages ago. anyways what gearbox are u using. just the grubee skyhawk. and dose the engine hold up good under constant 25-30mph cruising.

    oscully
    yea i guess thats about the smae price as the grubee gearbox.
    yea with the ez moterbike you can only buy the kit. you cant purchase the drive system seperatly. i just need the engine, mounting plate and drive system. i dont need sprockets, the gas tank, throttle, clutch, muffler, stuff.
    plus its alittle out of my budget. im looking to spend between 290-350.
    i might look into jackshafts but im sure there gonna be very expensive.
     
  5. ocscully

    ocscully Member

    A 10t or 11t driver on the output shaft and a 44t driven on the rear wheel is a reduction of either 4.4:1 10t or 4:1 11t (divide the larger 44t driven by the smaller 10t or 11t driver) With this amount of reduction you would have in theory a very high top speed but you would never be able to pedal the bike up to speed, to take advantage of it. Do a search for gear ratio calculator posted by jpilot here. It is a great tool to help you understand gear raitos and how they effect speed at any given engine rpm. The 4-stroke kits come with a total overall reduction of approx 18.75:1 With this amount of reduction you can expect to be able to go from stop to approx 32 mph. I believe Hough uses a bit smaller driven sprocket on his bike with the grubbe gearbox and reports speeds in the high 30's mph approching 40 mph, and says it will run all day in the high 20's mph to 30 mph.

    ocscully
     
  6. HoughMade

    HoughMade Guest

    I have the Honda engine with the Grubee Skyhawk II and it cruises easily and reliably at 25 to 30mph. I have had no problems with it.
     
  7. cspaur13

    cspaur13 Member

    wow on the gear ratio calculator 11 t drive sprocket and 44 tooth on the rear 26' wheel with the hondas 7000-7500 rpm. dont remember exact number. but my speed was like 135-145mph. wow thats pretty crazy. im not to sure if thats 100% accutrate. u'd have to pedla it up to 60-70 mph probally.
    im looking for that 25-30 mph crusing speed but going up to 40 once in a while is always a blast. but it would be nicer if i had a little higher crusing speed like 28-35 or so.
    have you ever had problems with the grubee gerbox. alot of people say its nice and alot dont.
     
  8. cspaur13

    cspaur13 Member

    well mabey it work. i put 10 tooth dirve sprocket with 56 rear sprocket. and if i kept the rpms under 4000. 2000 was 27.1mph. 3000 is 41.4. 4000 is 55.
    idk if they make bigger sprockets or not. bt it might be possible if i get a jackshaft or have a big rear sprocket and small drive 1 and kept it under 5000 rpms which would be crusing speeds and not killing the engine.
     
  9. cspaur13

    cspaur13 Member

    kings sales sells sprokcets up to 80 teeth and even above. 72 to 80 would be my best bet. at 5000 rpm crusing speed is about 45. i'd have to get the bike going to about 15-20 mph. mabey little less like 12mph.
     
  10. Youngbird

    Youngbird Member

    Go thru DAX....get the Titan Engine and the Titan Gearbox(5:1). It has a 10 tooth driver then all you need is a 40(ish) tooth rear sprocket....Good to go. You will need all the accessories, but its a good way to go.
     
  11. fetor56

    fetor56 Guest

    If your still concidering a Honda engine be advised the Titan PTO will NOT fit the Honda in it's standard form.....it needs a clutch housing that i believe Staton sells(expensive though),OR simply buy the HS engine(or Dax's engine as Youngbird said)
    Agreed about contacting Duane,he bought a Honda engine to test all this out.
     
  12. cspaur13

    cspaur13 Member

    isnt the titan $370 or something like that for the whole rear mounted kit.
    like with the jackshaft and mount and throttle. i was gonna look on go kart sites and stuff and see if they sell the centrifeugal clutches with the sprocket attached for the honda shaft. i know i would need the staton housing and stuff. it isnt cheap either.
     
  13. ocscully

    ocscully Member

    The Titan Gearbox reverses the rotation of the output shaft, plus the Titan motor with its PTO unit attached is 11 &3/4 in. wide. These are not problems with a rack mount and a jackshaft but are problems if you want to mount the motor in the frame.

    ocscully
     
  14. fetor56

    fetor56 Guest

    cspaur...has your basic idea changed,or are u continuing to think the same(Honda engine/in-frame mount/gearbox)?
     
  15. cspaur13

    cspaur13 Member

    nope. still for the honda. just wondering about the titan since he brought it up.
     
  16. Youngbird

    Youngbird Member

    Yes....the Titan Gearbox does reverse the rotation but thats overcome by mounting the engine"backwards"....ccw turned 180 degrees is cw. No problem. Right? And the gear box is about 29.99....Titan Engine is 175.00.
     
  17. fetor56

    fetor56 Guest

    The Titan is a good system,3rd generation.
    PM FireBellyCycles & ask how his tranny is going....it should be pretty near to completion.
    I don't recommend the Grubee & there's NO chance of u getting Quenton's as a standalone item.
     
  18. fetor56

    fetor56 Guest

    Out of curiosity i physically sized-up the Titan engine/PTO on a Grubee base(exhaust forewards) & unless i'm missing something it's unrealisticlly wide,plus the output sprocket has the wrong rotational direction.
     
  19. Youngbird

    Youngbird Member

    Turn the motor 180 degrees (shaft on right)....then it works
     
  20. fetor56

    fetor56 Guest

    Agreed;confusion cos your talking about a rack mount & cspaur stated(and continues to state) he wants a frame mounted Honda engine,tranny unknown.
     
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