Exhaust for GXH50

Discussion in '4-Stroke Engines' started by conradcliff, Nov 9, 2008.

  1. conradcliff

    conradcliff Member

    Ok, so I've been searching and searching for exhaust solutions for the GXH50. Does anyone make a different pipe for this thing than the stock box? Or are small engine exhaust ports basically all the same and no matter what I buy will work. I don't really want the little guy blowing his exhaust all over me every time I ride. Someone must have come up with a solution for this I just know it..

    As always, thanks for any help you guys can provide. :D

  2. Asked this before

    Did you buy the Grubee kit that has the new pipe and muffler included?

    I did and wanted to know why the outlet was so small.

    If you go to a thread I posted recently this may give you some answers.


    I have just finished my build except for the exhaust.

    If you read the thread it may not have any baffling so I want to get some fiber optics down the main pipe and look up the pea shooter end to see.

    If this is the case then surely the inlet hole should be the size of the outlet.

    Last edited by a moderator: Nov 10, 2008
  3. HoughMade

    HoughMade Guest

  4. biketec

    biketec Member

    Is your bike a rear mount? If so we do have a pipe it looks the same but exits out the side and has an adjustable elbow on it to direct it back or down.
  5. $-stroke confusion

    Hi Guys, this I know a little about.

    MOST exhaust on single cylinder 4-strokes is the size, or larger than, the exhaust valve, tho usually larger.

    HS/JL pipe for kit is oversized 2-stroke pipe has 2 long tubes inside like all the China-Fires do.

    HS/JL long pipe, have not tried it for sound yet, empty inside large muffler can, still has 2-stroke stinger on it.

    Honda Box muffler, amazingly quiet, seems to have little to no restriction, could have tail-pipe stuck on it if someone wanted a really quiet bike, great performance (Factory tuned)

    EZ Motorbike brand EX-Pipe: this is a flexable exhaust, capable of being routed where needed on most any bike. Performance: no discernable loss from the stock tuned box, still starts as easy, winds up, and performs the same BUT now has a cool "Motorcycle" sound, in addition to moving the exhaust dump to the rear tire (on my bike). I chose the 1" ID system, tho the smaller pipe will go onto your stock header pipe (if you cut off the muffler).

    So far my favorite, for ease of assembly, sound, and overall performance is the EZ-Pipe.

  6. grezm0nkey

    grezm0nkey Member

    i havent gotten that far in my build to put the pipe on yet, but been wondering if i could bend my own exhaust to kinda flow with the frame. i bought the long poo poo from bike engines. cant say the quality is great. figured i could bend a pipe and weld on a exhaust base plate. dont know yet.

  7. conradcliff

    conradcliff Member

    Wow, thanks for the replies everyone, well these post definitely answer my questions but I think I may be going with a pocket bike engine instead of the GXH50. I'm still not sold on it yet but I'm starting to lean that way. If I do go with the GXH50 I'll definitely be refering back to this post though.

    Thanks again guys!
  8. Irish John

    Irish John Guest

    The long motorbike type silencer is very good and if you drill another hole the size of the existing outlet it makes a really good 4-stroke sound - especially with the Honda. There is no difference in power but the extra hole sounds louder. With the short pipe I wouldn't drill any extra hole because it would make it noisy and not any more powerfull. The short pipe has a baffle but the long pipe has none. The long pipe prevents you having a pannier bag on the left side because it gets hot. I like the long pipe and I also like the short pipe just as much because it is quiet and efficient. Holding the long silencer onto the bottom of the seat stays requires a couple of extra s'steel hose clips.
    If you put an oxycetelene torch onto the downpipe until it ripples you can get a high pitched 4-stroke racing engine sound like in the Honda TV adverts but after a while it begins to annoy yourself almost as much as your neighbours. You can change the speed of the throttle response by playing with the exhaust but you won't get any extra power. If the stock exhaust didn't look so naf I'd use it because it sounds really quiet but people might laugh at me! They'd only get to laugh once mind you!
  9. Performance

    Ok so the standard muffler has a very small outlet compared to the outlet manifold.

    Drag cars have a short straight out pipe for performance with the idea that the less you restrict the exhaust the better performance.

    Why don't the thing run any better if their is no baffling?

    I am about finished on my first 4 stroke build so have used the stock pipe at the moment.

    Has anyone used just a straight out pipe to see how it goes?

    I'd like to shortly maybe after I have drilled a few holes and done some other stuff to see if it changes anything as others have.

    Ok other internals will need adjustment but the overall idea would be tested.

    I am not considering the noise at this stage and I know it is quite important so you don't get noticed but would like to see how it goes using the principles used with a performance setup.

  10. Irish John

    Irish John Guest

    Yes I've run my bike with a straight through pipe which I can do by simply removing the silencer from the long downpipe. It sounds like a sporty tractor and exceeds permissable noise levels and power is actually considerably less. Don't even bother trying it cos it's a no brainer. I once did the same on a Suzuki GS 750 by removing the silencer and it lost 30 - 40% power but if I twiddled the timing I could make it spew flames out the end of the pipe like a WW2 Spitfire engine and that looked good at night but it was just for a 5 minute trial and a bit of a joke. The only way to get more power from the Honda GXH50 is to diet really seriously.
  11. fetor56

    fetor56 Guest

    "diet really seriously"....sounds about right to me.
    I've got a system on my Yamaha XT600 Motorbike called P.O.S.A(Pillion Overload Sensory Alert)...........if any fat chicks try to get on the back it won't start. ;)
  12. Pipes

    How did you know that - are you stalking me!

    Ok so the straight out pipe didn't work even though you tweaked it.

    I guess I'll just use the standard one.