Honda GXH50 Carb leaking

Discussion in '4-Stroke Engines' started by gcw, Jul 18, 2009.

  1. gcw

    gcw New Member

    This is my first MB build and I decided to go with the Honda engine. After completing it I was able to ride it about 15 miles when gas suddenly started pouring out of the carb. Since it was under warranty I took it into the local Honda dealer where they put on a new carb. I thought it was fixed, but after riding it approx. another 15 miles, gas was pouring out of the carb again. I took it back to the Honda dealer again and they said they found the carb bowl was loose, so they tightened it and said that should fix it. Rode it again for approx. another 15 to 20 miles when gas again was pouring out of the carb. I've checked the float bowl and it is tight. I suspect the float must be sticking causing the gas to pour out of the carb. It seems really strange that the orignal new carb would have a float to stick, but even stranger that (if that's the cause) that the replacement new carb would also have the float to stick. I've called SG Green Motors, where I bought the engine kit, and they want to sell me a Hua Sheng carb to replace the Honda carb, saying that will fix my problem. My local Honda dealer is now saying Honda doesn't want to warranty this engine because I'm using it for something it is not designed to be used for. Sounds to me like Honda is just looking for a way to get out of their 2 year factory warranty! I don't feel I should have to buy another carb (the Hua Sheng) to replace the Honda carb. I've only got 59 total miles on this bike and the way it is now, it is a "fire trap" between my legs! Has anyone else had this problem with a Honda carb? Any input will be greatly appreciated.

  2. Old Bob

    Old Bob Member

  3. Mountainman

    Mountainman Active Member

    have not heard of this recurring problem here on site
    is your engine mounted fairly level ??

    nice connection shared there Old Bob

  4. gcw

    gcw New Member

    The engine is mounted level. I've now pulled the carb off and checked the float. The float is currently not stuck and moves freely. However, I still suspect it is a float problem, unless someone has any other idea what is causing the problem. I did see in one thread someone mentioned a float sticking when they hit a bump. I don't understand why the float would stick when a bump is hit, unless there is something wrong with the float. The pin that holds the float on is loose (it will slide back & forth), but when the float bowl is on, it will keep it from sliding out. Is there any kind a lubricant that can be put on the float to keep it from sticking?
  5. biketec

    biketec Member

    I would say you might have a tank with a bit of poopie in it do you have a inline filter for her? that would be my uneducated guess !!!! :grin5:
  6. gcw

    gcw New Member

    Yes, I do have an inline filter on the gas line.
  7. fetor56

    fetor56 Guest

    I also had this problem from new(gas pouring out of the carby)
    My solution was to take it apart & clean it thoroughly.........thoroughly.
    Seems to me the machining tolerances by Honda are tooo fine allowing for the easily sticking of moving parts & the clogging of the minute holes by foreign objects.
    Doesn't pay sometimes to machine things tooo well.

    BTW...if u take it apart buy some cheap magnified glasses(1.5X+)
  8. velosolex

    velosolex Member

    carb leakage

    The Honda carb is a fine piece, the clone carb is almost as nice with the difference being in how the casting look and perhaps some of the machining finishes. The brass seat used to seal incoming fuel mates with a viton tipped needle that is pull down by the plastic float. The fact that the float and the pin that keeps it in place can move around is no problem. The float needs to rotate about the center of to bosses that the pin sits in, and the pin can slide side to side as it is captured by the float bowl when it is in position. I think there is a small spring involved (on the clone carb) but that is only to keep the needle from wandering from it's home position, seated in the floats tang. I don't know what Honda uses for this securement (sp?). With that said: the viton tip on the needle does the sealing against the brass seat that is either screwed into the carb casting or pressed it :thinking: Most if not all motorcycle carbs are built this way and have been so for some time. The only improvement in this design was the introduction of the viton tip some years ago. When I got started in all this business ('60's) we had metal needles seating against metal.....and for the most part, it worked. We always turned off out fuel petcocks :sweatdrop: or else.....disaster. With that being said, your leaking carb is a mystery to me if you have a clean gas tank without paint on the inside :rolleyes7: or rust :shout: and you know your filter is clean :grin5: BTW, inline fuel filters do not do well with gravity feed for some reason. I've had good luck with them when there is a straight shot between the tank and carb, but when you have a lot of horizontal fuel line, things can get out of control.

  9. Mine did that too. It had debris in it. Take it apart & clean it. Drain your tank & look to see if your gas has garbage in it. Any rust or crud in your tank will cause it. Is your gas tank vented? Try driving it with the gas cap off. My Whizzer tank was not vented at all & starved the motor of gas causing it to die then gas wiould just start pouring out of it.
    Last edited by a moderator: Jul 22, 2009
  10. velosolex

    velosolex Member

    Paint and rust.....bad news for carby's. Whats even worse is a carb with water in it and white rust setting in!

  11. glacknoid

    glacknoid Member

    Like Zomby said if your tank cap isn't vented properly pressure will build from the gas sloshing around in the tank and the gas will be forced out the fuel line into the carb pushing the float down and flooding out the overflow in the carb untill the pressure is released. That happened to me untill i replaced the gas cap which didn't vent. As far as a rusty tank goes buying a product called Kreem from a motorcycle shop works great to treat the inside of these cheap little gas tanks to make them completely rust proof.
    Last edited: Jul 26, 2009