exhaust straight pipe after stock muffler

[Trey]

Hello. I looked around but didn't find this. If I am mistaken, please let me know. I have a 49cc 4-stroke HuaSheng. It has a stock muffler with a 6mm long exhaust tube with a 1.6mm outside diameter. It's quiet enough I guess, and I'm not really trying to improve performance. What I want is to stay clean. I'm considering bending a larger diameter pipe to exit past the rear hub, and attatch to the stock exhaust tube. I am able to arrainge the appropriate bracketry. What I'd like to know is what effect this will have on the engine? Does the diameter of the pipe I add make much difference? I could have some welding done if anyone has a proven design. Thanks for any guidance you can give me!

 

[the chief]

to over simplify, your exhaust pipe is only as big as its smallest point, once again this is oversimplified, most likely, you will only notice a change in sound.

 

[Trey]

Oversimplified is dead center of my pay grade, thank you for the info. My hope was to not make much of any change other than staying clean. Sounds like I can plan it out.
If anyone has some lessons learned doing this, that would be helpfull too...

 

[GearNut]

A larger diameter pipe that is long as well will lower the tone of the sound.
My bike does not sound like a 49cc engine at all.

It is 1 3/4" diameter, 27" long.

 

[Trey]

Thanks for the pic GearNut. Has a nice 'factory orderly' appearance. It looks to be the same bike and engine I've got. Proof of theory on the pipe, it's in the plan. Thanks for the help!

 

[unimog]

Phantom Long Barrel Exhaust Pipe Custom Exhaust with Fiberglass Packing Hand Built in USA
Part No: B-8000 Price: $ 125.00
Is Pretty sweet. The san diego guys have them that i ride with and the dont sound stock at all.

 

[Trey]

Holy mackerel! $125 is too much for me my friend. I will look at their stuff and see what I could do with their designs though. I got my cruiser with 49cc for $50, so I really should'nt moan about anything I've gotta pay! Thanks for the reference. Diego? Why are you indoors? lol

 

[maniac57]

Holy mackerel! $125 is too much for me my friend. I will look at their stuff and see what I could do with their designs though. I got my cruiser with 49cc for $50, so I really shouldn't moan about anything I've gotta pay! Thanks for the reference. Diego? Why are you indoors? lol

You might get lucky and find some tapered pipe somewhere for a megaphone. They help the sound a lot. I found a table leg I made an extension out of for a stock china girl and I loved the sound. That's probably the cheapest route.
(can't find the pics, sorry.)

 

[mybike1]

Looks great... Long pipes always sound good

 

[Trey]

maniac57- I'm going for just about what GearNut has. I've decided on a military theme, so mine will be painted. Hoping to use some thin wall pipe my welder friend has laying around. Was thinking about a pipe larger than the stock exhaust in order to fit it easilly. Does it make a big difference in the sound? Mine sounds good now. Or if I can get barter, I may just have him weld a flange to a pipe, that goes to a fitting for a replacable muffler. Long-term budget.

 

[maniac57]

maniac57- I'm going for just about what GearNut has. I've decided on a military theme, so mine will be painted. Hoping to use some thin wall pipe my welder friend has laying around. Was thinking about a pipe larger than the stock exhaust in order to fit it easilly. Does it make a big difference in the sound? Mine sounds good now. Or if I can get barter, I may just have him weld a flange to a pipe, that goes to a fitting for a replacable muffler. Long-term budget.

Yes, bigger pipe affects the tone a lot. Try to use some thicker tubing to suppress the tinny notes and the engine will sound larger. (Thinwall tends to amplify the ringing in a two-stroke)
A long pipe leading to a big section and a muffler at the back will work very well.

 

[Trey]

"affects the tone alot"? I don't want it any louder than it must be. Rode it for the third time today and it is really quiet- you can easily speak in a regular voice while it's idling. It's quiet enough while I'm riding that I'm not concerned with bothering anyone, even on those still evenings. Don't know what I was thinking about the tubing- of course thicker is better. (Build it right- long term budget.) Do you believe the big section before the muffler is nessicary? Do you have a tube diameter and muffler recommendation? It's a 4-stroke HuaShwaun (or whatever), stage 3 Grubee gearbox, and I thank you for the help.

 

[GearNut]

"affects the tone alot"? I don't want it any louder than it must be. Rode it for the third time today and it is really quiet- you can easily speak in a regular voice while it's idling. It's quiet enough while I'm riding that I'm not concerned with bothering anyone, even on those still evenings. Don't know what I was thinking about the tubing- of course thicker is better. (Build it right- long term budget.) Do you believe the big section before the muffler is nessicary? Do you have a tube diameter and muffler recommendation? It's a 4-stroke HuaShwaun (or whatever), stage 3 Grubee gearbox, and I thank you for the help.

Here are the parts I used to make the exhaust.

Handlebars off an old exercise bike, small muffler (1/2" MIP thread) from ACE hardware and some flat stock to make the cylinder head flange.

I have since made a custom baffle that slides inside of it. It is a glasspack design with a diffuser at the exit. Nothing restrictive, even quieter still and it retains the nice deep tone.

The lawn mower muffler alone was not horribly loud but I wanted it quieter.

 

[Trey]

Yes sir, that is what I needed to see. Thank you. Glad you took photos thru-out, I'll begin doing that tomorrow.

 

[GearNut]

I had to weld a ground to fit washer to the end of the muffler inlet. When I had the exhaust coated it broke right where the threaded inlet pipe goes into the muffler body. The polishing process brought out the weakest place, the super thin metal that occurs when they stamp out the muffler body from a piece of sheet metal. It is an easy reinforcement to do, just thought I'd warn you about it.

 

[Trey]

The guy whose steel stock I'll be carrying in barter for the welding will be glad to have some info. He rarely does thin stuff. I'm approx 90 days out on the exhaust build. We still havn't had winter yet!

 

[maniac57]

Old hadlebars work very well. The thicker pipe affects the tone, not the overall loudness. Thicker pipe tends to sound less raspy and annoying, more like a bigger motor.

 

[maniac57]

Here is the one I built from conduit.
http://i875.photobucket.com/albums/ab318/maniac573/enginekitpictures038_zps7810c79b.jpg
http://i875.photobucket.com/albums/ab318/maniac573/enginekitpictures033_zps2e4df3d0.jpg
Here's the table leg version. (Pardon the ugly welding, it was only a prototype)
http://i875.photobucket.com/albums/ab318/maniac573/enginekitpictures051.jpg

 

[Trey]

Nice! I've got plenty of time to measure and plan, so I expect mine will be ok, whenever it get's done! Good ideas here.

 

[LabRat]

You may get the tip you want by looking to play it again sports check out the used baseball bats. Work great!