4 stroke Honda Service Intro

Discussion in '4-Stroke Engines' started by Earth Mechanic, Aug 7, 2007.

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  1. :D:D:D

    Hey folks, Im posting this thread as the first in a series of posts that will hopefully help guide me and anyone else through service of their new 4 stroke motor. This thread relates explicitly to the Honda GXH50 4 stroke.

    The pics are a general introduction to the motor and motor casing, carb and carb adjustments, and preliminary observations about the motor after 100 hours of use. I know there are many experienced riders / mechanics out there, so I hope this will be useful and not trite. The next post will be valve clearence adjustment where im going to space the exhaust and intake valves at top dead center (tdc) to hopefully get rid of the ticking noise which is robbing my motor of power, could potentially cause a bent valve rod, and just plain annoying.

    1. Non Drive Side
    2. Carbonized Exhaust
    3. Carb Diagram
    4. Head Cover Removed


    Attached Files:

    Last edited by a moderator: Aug 9, 2007

  2. stowaway

    stowaway Guest

    great info

    great info.
    looking forward to hearing all you have to say. Im not mechanical at all. but im trying.

    ive got the heushen 4 stroke engine. but it seems quiet similar. and one day i plan to upgrade to the hona motor.

    btw. how fast do you get on this motor? (w/ what size sprocket?)
  3. How fast you say?

    Well, I have a heavy, but sturdy, bike. And i get up to 35 mph. I have the 56 tooth sprocket installed now, but also have a smaller sprocket. I pedal start my bike because it bogs down the motor otherwise, but i dont want to change to the smaller gear because i think it will limit my top speed (and its a bugger to change those dang sprockets!!!)
  4. iRide Customs

    iRide Customs Member

    Looks like we're going to get some very good, helpful info from you. Thanks!!
  5. stowaway

    stowaway Guest

    limit ur top speed

    limit your top speed?

    dont you get more top end speed with a smaller sprocket??
  6. gone_fishin

    gone_fishin Guest

    wait, wait...this is too good a topic to distract with off-topic...let's keep this as clean as possible, please, as it looks like future wiki-"owner's manual" material...

    stowaway: i don't wanna squash your question, tho...feel free to jump in on an existing ratio discussion, or start a new topic specific to the 4-strokes...with pics, of course :)

    Earth-Mechanic: everyone at MBc appreciates this kind of contribution, and i'm personally grateful for your involvement...please do continue 8)

    ps-i don't think you can rate your own topic...anyone who wants to give kudos to a good thread, just click on "rate this thread" at the top of the topic.
  7. vintagebiker

    vintagebiker Guest

    Looks like you had an exhaust leak (pic 2).
  8. I wondered about that. actually, the gasket from my exhaust manifold to the exhaust pipe crumbled when i took it all apart. Thankfully i have another gasket, and will replace when i put this mofo back together. Do you think this could have caused the pinging? Thanks for the reply vintageOG!
  9. vintagebiker

    vintagebiker Guest

    An exhaust leak can be the cause of weird noises.
    Even can cause popping or backfire type sounds, usually on deceleration.
  10. HoughMade

    HoughMade Guest

    I agree. An exhaust leak, especially right at the port, has a very sharp sound that does not sound like the roar when a leak is further downstream. I would check the valve clearance, adjust if neceesary, then put it together with the new gasket to see what she sounds like.
  11. Jim H

    Jim H Guest

    Does sound like the noise you describe(exhaust leak). Back in the day we gapped our headers with washers which made metallic clicking noises.
  12. gone_fishin

    gone_fishin Guest

    well, you asked earlier about a tick, i agree with the guys...when an exhaust leak's still pinhole, it'll "tick"...there's your answer.
  13. Will do guys, thanks for your help here.
  14. throttle set up


    I have attached a pic. The short answer is that the throttle system is more complicated than it my seem because it is linked to the carb and to the governer arm. If you start your engine you will notice that there is a lever that moves up and down that controlls the throttle (the motor will rev if you move it up and down). above this lever, there is a barrel adjustor.

    note: it is not a straight line between the notch in the throttle arm where your throttle cable is supposed to go through and the barrel adjuster...go figure?? I got around this by bolting on a piece of metal from a motorcycle carb to extend the throttle lever and give more torque to the lever which resulted in a smoother throttle feel...i recommend this. you will have to improvise to find a throttle extender that works.

    Attached Files:

  15. Herrmanator8

    Herrmanator8 Guest

    i plan to buy the mounting kit from bicycle-engines.com and then buying the gxh50 from smallenginewarehouse.com and im guessing that the throttle hookup system comes with the mounting kit. also, have you noticed any problems with your engine??? just wana make shure i buy the right thing and not another piece of ****... do you know if the honda gx100 3.0hp will work??? or will it just destroy the gearbox and bike?

    thanks jon