muffler for 4 stoke engine

Discussion in '4-Stroke Engines' started by jimj, Aug 2, 2016.

  1. jimj

    jimj New Member

    Hi:
    I have a 4 stroke 49cc HS engine. I saw an article about using a 2 cycle muffler on this engine giving it more power and better breathing as the engine has the square box muffler.
    Will a muffler come with the necessary clamps, gasket etc. for installation or do I use the ones from the square muffler? I think the muffler gives it a better look too. I read also that a flexible pipe going under the engine is another option. Which is quieter and better sounding?

    Thanks for any suggestions.
     

  2. bakaneko

    bakaneko Active Member

    Some come with the gasket and some don't but you will need a gasket as the stock exhaust does not have a gasket. And, you will also need a muffler holder as you do not want the bolts to shear also probably good to get steel bolts replacements. The standard 2 stroke muffler will require you to install the extended pedals if it is not on there already as the muffler will interfere with normal pedals (atleast it did for me).

    I am liking the design of the long racing header mufflers, which is suppose to give more middle and top end power. And, it looks like it snakes under the bike so no need to put the extended pedals on. This site is sold out but you get the idea...

    http://www.affordablegokarts.com/mm...de=A&Product_Code=22110&Category_Code=MTRBK49

    Video of guy with the muffler. that sound is it produces is louder but nice

     
  3. jimj

    jimj New Member

     
  4. jimj

    jimj New Member

    Bakaneko that is a cool sound for a muffler but pretty loud. I was looking at the 2 stroke muffler as it seems harder to find a 4 stroke muffler. I know some kits show a regular muffler than the square stock one. Don't know if its the 2 stroke, but to me a muffler is a muffler since I am not looking for a high performance out of the engine as I am too old for cruising around at full throttle. I will be using the SBP shift kit for this engine as my bike a Fito Modena GT2 has rear disk brake so adding a sprocket is probably too tight. KCVale has a more direct drive shifter but it is more expensive so I went with the SBP, and I like the extra rear bracket that connects to the engine mount that I think gives the mount more rigidity to keep things from moving around.Pedaling on a dead engine may be a big hassle though.
    Getting back to the 2 stroke muffler. How do you connect the flange to the engine block, because I saw a muffler with only a flared end . There is also one with a 2 bolt flange which bolts to the engine. I suppose the bolt hole spacing is different between the 2 stroke vs. 4 stroke engines. I have to watch for the proper fitting muffler huh?
    Thanks for your reply, much appreciated
     
  5. CrazyDan

    CrazyDan Member

    I picked up a 4 stroke exhaust from boygoesfast on eBay, had to file some bumps down on the flange but other than that was in great condition. Sounds awesome and I believe the baffles inside are less restrictive than the exhaust that come with the bikeberry kit. Bolt pattern between the 2 stroke and 4 stroke are the same, only difference is the angle the pipe is welded to the flange.
     
    Last edited: Aug 3, 2016
  6. jimj

    jimj New Member

     
  7. jimj

    jimj New Member

    HI Dan; Hey thanks for the reply. I guess I will need the 4 stroke muffler as you mentioned the angle of the pipe is slightly different from the 2 stroke. I was looking more for a all black muffler but I guess I will have to settle for the chrome as I don't see a black one for the 4 stroke. Maybe I'll e-mail them and ask if there is a black one for the 4 stroke. Good to know that the bolt pattern is the same as I was wondering about that. What kind of gasket did you use for the mounting and did you buy bolts?

    Good tread, thanks.
     
  8. Frankfort MB's

    Frankfort MB's Well-Known Member

    You could use the 2 stroke pipe and just bent it too fit
     
  9. jimj

    jimj New Member

    Yea, that might me the way for me to go as my bike is all flat black so a black muffler will blend in good.

    Thanks
     
  10. CrazyDan

    CrazyDan Member

    As jimj said you can use a 2 stroke exhaust, just gotta bend it some to fit. Pack the pipe with sand to prevent kinks. Not sure if you want to use a torch to heat up a black exhaust, but it'd be easier.

    I'm searching for a 28.5" long, 7/8" inner diameter stainless flex tube. Then my current exhaust will be chopped down to a 4" nub and that flex tube clamped on. At that point it wouldn't matter if it was a 2 or 4 stroke exhaust.

    You can also purchase heat resistant paints of virtually any color that would work on the exhaust.
    Rust-oleum makes a heat resistant line good up to 1200F.
     
    Last edited: Aug 6, 2016
  11. jimj

    jimj New Member

    That's a good idea to put sand in the pipe to keep it from kinking and yes I would use a mepps torch to heat the pipe first before trying to do any bending.
    I got a can of barbecue grill black paint to use if the paint scorches . I don't know if it will hold up to 1200F though.

    Hope you find your flex tube for the exhaust. I have no idea where you could buy something like that. Maybe someone in China makes those for a reasonable cost.
     
  12. CrazyDan

    CrazyDan Member

    I've found a couple sources online, but I prefer buying online as a last resort if I can't find it in a store nearby. Hoping to find something at one of the many local hardware stores around, the couple I went to just carried copper tubing with a 7/8" inner diameter. It's another reasonable way to go and I've seen people have threaded fittings on the tip for a removable muffler.
     
  13. mbmystery

    mbmystery New Member


    I got the whizzer stainless flexi-exhaust from memorylane classics website/ store. It was something like $38 delivered including clamps and a little fishtail for the end.

    It's a tad longer than that but you could trim it for proper tuning. Wrapped it with the black fiberglass and black silicon spray. Looks great. Sounds pretty good, and did lower the dB/SPL by a bit. Might put a small lawnmower muffler on it one of these days.

    If the website is still down look it up on internet archives. They have a ph # & I was able to order right over the phone.
     
  14. Jcs1989

    Jcs1989 New Member

    If your good with fabricating up your own stuff. You can use old handlebars and attach a Briggs muffler at the end. Here's a link to the exhaust I've fabbed up myself. With scrapyard part finds an old set of cruiser handlebars..
     
  15. BakkenRide

    BakkenRide New Member

    i have had the best performance running a straight pipe, loud but sounds good. I bought the glass pack pipe from phantom bikes, but after a few months the glass packed muffler piece broke off from vibration (probably the way i installed it ) so i just took it off and found it increased power and speed.
     
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