Custom exhaust

Frank Bullitt

Frank Bullitt

New Member
#1
#1
I spotted some 3/4" and 1" electrical conduit at home depot they even had prebent 90 degree pieces which I would think make an excellent use for custom exhaust fabrication. Have any of you used this material for this purpose before? It looks like alluminum in the photo but actually is steel I believe it is galvanized.

 
Beetlejuice

Beetlejuice

New Member
#2
#2
Thats called EMT tubing used mainly for wiring commercial buildings.

I don't know if it will last that long under the heat your engine will put thought it.
 
Frank Bullitt

Frank Bullitt

New Member
#4
#4
I would take off the galvinizing with muriatic acid before welding. Of course those fumes are pretty bad too! My concern was the quality of metal which I am sure isn't ideal and that is is kind of thin. I will give it a try though as it is pretty cheap.
 
B

blownengine

New Member
#5
#5
Thats kind of like what i am doing with my HS50. I bought a piece of tube about a foot long with threads. It screws right into the exhaust of the engine and i will weld a Briggs muffler on the end. The tube is pretty thick so im not worried about it lasting.
 
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Bushman

New Member
#6
#6
If your using the kind of tubing or pipe I think your just be aware the inside diameter is smallee than regular exhaust pipe and it will restrict air flow some what. But, it may not make a huge difference on a stock engine.
 
Oldsalt

Oldsalt

Well-Known Member
#7
#7
Next time you see a junk weed eater grab it. The bend in the shaft is very useful for making mini bike pipes. There is a plastic liner inside. But after cutting the pieces to the required lengths the plastic is easy to push out.
 
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blownengine

New Member
#8
#8
Bushman, the pipe im screwing in is skinnier on the inside. It will restrict the flow some but im not building a monster. I just hope building my own exhaust wont give me a poor idle or performance
 
65ShelbyClone

65ShelbyClone

Well-Known Member
#9
#9
I have used steel conduit like that for headers and it works decently. It's just a chore to get the galvanize off so it can be welded.

Somewhere around here I have a .750" header I made for an Tec OHH65.
 
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Frank Bullitt

Frank Bullitt

New Member
#10
#10
Well guys finally completed my exhaust. My first task was to cut the flange off the original muffler. I decided to open the muffler and see what was inside.
I started out with a straight piece of conduit and tried to make a bender and use the hydraulic press. It kinked it really nicely! But gave up trying to make it work if it ever could? I broke down and bought some 90 degree bends and gave it a go. I had a good idea of what I wanted it to look like I sorta wanted a classic triumph type look to it. My initial mock up was way to complicated and by luck I held up a piece which was to become the back half of the exhaust looked really good and placed the muffler just where I wanted it. So hours wasted on the first half really made me feel dumb! After getting everything mocked up I poured some muriatic acid in a container and stripped off the coating on the muffler and the pipe. I then welded everything up. I think it turned out really nice. I may use a piece I cut a angle cut on the end weld onto the muffler to give it some more style. BTW the muffler is the standard universal $3.98 muffler I bought at Lowes.
After test riding it quite a bit it is about the perfect sound to me quite a bit louder and deeper than the stock one and hopefully a lot less restrictive. Now I just need to clean it up and paint it or something.



 
G

GTO

#11
#11
That can burn somebody parked or just sitting warm in the garage.

I wonder why all the doodles with custom exhausts stick outside the frame.
 
Frank Bullitt

Frank Bullitt

New Member
#12
#12
Great if you are stupid enough to grab an exhaust pipe without knowing if it is hot or not than you probably deserve to get burned. We all have stoves in our houses right? Do you ever just grab the stove for fun? Anyways I never bring a hot motorcycle or minibike right into the garage I leave it outside a while to cool off.

I think the reason the exhaust on these bikes stick outside of the frame is there isn't much room to put it anywhere else. I did think of running it under the seat and end it before the handle on the frame but it didn't look good, also it would be much more complicated though attaching a mount would be pretty easy.
mine looks the way it does for many reason one because of the radius of the bend in the pipe is fairly large. The muffler is pretty big for the space. The location of the exhaust port on the motor. I didn't want to have kinks or weird bends to cause restriction. And I wanted it to have a motorcycle look and be pleasing to the eye instead of something that looks thrown together.
I do wish the muffler looked better but for $3.98 and how it sounds I can't complain.
I plan on cutting some better flanges on the plasma. The stock ones have round cutout for the exhaust port whereas the port on the motor is D shaped.
I also think some heat shields with holes cut in would look cool.
 
G

GTO

#13
#13
Frank Bullitt said:
Great if you are stupid enough to grab an exhaust pipe without knowing if it is hot or not than you probably deserve to get burned. We all have stoves in our houses right? Do you ever just grab the stove for fun? Anyways I never bring a hot motorcycle or minibike right into the garage I leave it outside a while to cool off.

I think the reason the exhaust on these bikes stick outside of the frame is there isn't much room to put it anywhere else. I did think of running it under the seat and end it before the handle on the frame but it didn't look good, also it would be much more complicated though attaching a mount would be pretty easy.
mine looks the way it does for many reason one because of the radius of the bend in the pipe is fairly large. The muffler is pretty big for the space. The location of the exhaust port on the motor. I didn't want to have kinks or weird bends to cause restriction. And I wanted it to have a motorcycle look and be pleasing to the eye instead of something that looks thrown together.
I do wish the muffler looked better but for $3.98 and how it sounds I can't complain.
I plan on cutting some better flanges on the plasma. The stock ones have round cutout for the exhaust port whereas the port on the motor is D shaped.
I also think some heat shields with holes cut in would look cool.
Click to expand...
No, I didn't grabbing it meant bumping into it while riding or standing around it or getting something in the garage. I've bumped into one that only stuck out two inches, still have a big scar. :doah: A kid could get burned pretty easy when looking away for one second. (they are attracted to mini's) Looks like it sticks out quite a bit so that was my thinking.

I like those mufflers (my favorite) and use them all the time. :thumbsup:
 
Oldsalt

Oldsalt

Well-Known Member
#15
#15
A guy can always wrap the header if there appears to be a danger of getting burned. The attached picture shows a second method, a heat shield. Just rolled [and hammered] a piece of sheet aluminum and attached it by welding some 10-32 nuts onto the megaphone. By the way, this Briggs Animal is really loud. The megaphone made the engine run lean until I drilled out the main jet for the third time. This is my fastest mini but it is sorta dangerous for a new rider that thinks all mini bikes have got to be toys.
 
Frank Bullitt

Frank Bullitt

New Member
#16
#16
It looks like it sticks out more than it really does. It definitely sticks out more than I would like but I like it just fine and it is clear of my leg when on it. I sat on it when I was mocking it up and the exhaust actually tucks in quite nice I think it would be tough to burn myself.
I don't think I have ridden this without pants on yet though. But if I ever burn myself I might just have to put some shields on.



I notice the motor pops now when coming off throttle I thought this means its running rich? I pulled off the air box cover to try to compensate with the better flowing exhaust. But it still seems to do it. Also It doesn't start without the choke on even when warm. But it has always done that.
 
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delray

delray

Well-Known Member
#18
#18
Frank Bullitt, why don't you just make it easy on yourself and cut off back handle grip tubing and weld it higher or lower or just keep it off and then just snake the exhaust under the seat and out the back:thumbsup:
:scooter:........then again i wouldn't know anything about that:eek:ut:

 
G

GTO

#19
#19
I'd just change the angle, the bike has enough cuts already! :doah:

BTW the bike you showed is just asking to burn a hand if some friend grabs the back without asking! Make it shorter. Hell a guy could point the thing to the right as well.

Looks like need to do one to show the way it's done. :thefinger: Hahahahah
 
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