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custom exhaust


Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. I'm want to make a custom exhaust that utilizes the original muffler and flange. What type of metal tube ...
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Old 11-05-2009, 11:54 AM
pwrobleski's Avatar
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Question custom exhaust

I'm want to make a custom exhaust that utilizes the original muffler and flange. What type of metal tube or pipe should I use for the piping? I gonna take it by a muffler shop and have them custom bend it to where I want to route it. Then I'm gonna take it to a place and have it powder coated. So whats the best material and thickness of the sidewall for my application?

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Old 11-05-2009, 12:32 PM
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Default Re: custom exhaust

Um... might be better off at an "Industrial Metal Supply" or a general welding shop - even plumbing perhaps. I doubt yer average exhaust shop has the tooling for bending such a small diameter. I'm pretty sure powder coating won't last on such a high heat application either.

All is not lost however - the gauge yer talkin about is pretty easy to bend, just gotta pack it with sand and cap both ends (welded) and you should be able to bend it yourself. The sand is to keep it from kinking - and the exaust shop would have the same problem, with the larger pipe it caves in the side a bit even with their benders - they just don't care with that "large" a pipe.

And ofc any high-temp rattlecan paint will look sweet


Yet - have you checked out this: Sick Bike Parts tuned exhaust? Not only will it give ya the length yer after - you get a pronounced power boost as well...

Just a thought
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Old 11-05-2009, 01:00 PM
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Quote:
Originally Posted by BarelyAWake View Post
Um... might be better off at an "Industrial Metal Supply" or a general welding shop - even plumbing perhaps. I doubt yer average exhaust shop has the tooling for bending such a small diameter. I'm pretty sure powder coating won't last on such a high heat application either.

All is not lost however - the gauge yer talkin about is pretty easy to bend, just gotta pack it with sand and cap both ends (welded) and you should be able to bend it yourself. The sand is to keep it from kinking - and the exaust shop would have the same problem, with the larger pipe it caves in the side a bit even with their benders - they just don't care with that "large" a pipe.

And ofc any high-temp rattlecan paint will look sweet


Yet - have you checked out this: Sick Bike Parts tuned exhaust? Not only will it give ya the length yer after - you get a pronounced power boost as well...

Just a thought
Do you think in even kink with a mandrel bender? And what typed of piping would you suggest? And gauge? Would reg steel conduint work, black iron pipe, stainless, not sure which one i want to use. I use to make custom conviers so I have knowledge for material. Just not much for making a exhaust, lol



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Old 11-05-2009, 01:10 PM
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Default Re: custom exhaust

Can't remember who, but someone here used a bicycle handlebar for exhaust tube.
SB
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Old 11-05-2009, 01:11 PM
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Default Re: custom exhaust

Quote:
Originally Posted by BarelyAWake View Post
Um... might be better off at an "Industrial Metal Supply" or a general welding shop - even plumbing perhaps. I doubt yer average exhaust shop has the tooling for bending such a small diameter. I'm pretty sure powder coating won't last on such a high heat application either.

All is not lost however - the gauge yer talkin about is pretty easy to bend, just gotta pack it with sand and cap both ends (welded) and you should be able to bend it yourself. The sand is to keep it from kinking - and the exaust shop would have the same problem, with the larger pipe it caves in the side a bit even with their benders - they just don't care with that "large" a pipe.

And ofc any high-temp rattlecan paint will look sweet


Yet - have you checked out this: Sick Bike Parts tuned exhaust? Not only will it give ya the length yer after - you get a pronounced power boost as well...

Just a thought
With the exhaust from sbp, whats the use for the 2 springs- do you know? lol
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Old 11-05-2009, 01:15 PM
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Talking Re: custom exhaust

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Originally Posted by silverbear View Post
Can't remember who, but someone here used a bicycle handlebar for exhaust tube.
SB
hey thanks for that idea, good one

Last edited by pwrobleski : 11-05-2009 at 01:16 PM. Reason: grammer
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Old 11-05-2009, 01:27 PM
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Default Re: custom exhaust

Most exhaust is mild steel stock, I'm sorry but I've no idea the wall thickness - me and numbers lol However - mild steel of that size is fairly simple to bend yourself. Any two points of contact and leverage will do it, best if you can find a round surface - but just about anything will do. People 'round here have used conduit with success - I've just not messed w/it myself.

Lotsa lil bends to make a big or sharp bend, that's all there really is to it if you haven't a proper tubing bender. If yer going with stainless tho it's another matter - that stuff is rugged and somewhat brittle/prone to cracking from bending abuse. I personally think stainless is great - but maybe not worth it for the do-it-yerself... maybe not for this application either - I'd just make another if I needed to. It's all up to the builder tho

I'd still go with a tuned exhaust, even a custom job - over a regular pipe & can. It's just too much a response to overlook - the 2 stroke begs for 'em lol

The two springs on the SBP's pipe are because it's a flexible joint. Common to see on other "small" 2 stroke vehicles like snowmobiles and ultralights, it helps reduce metal fatigue due to vibration and torque flex. It is usually a ball & socket joint, the SBP's one also gives more options for mounting orientation.

There's a buncha sweet expansion chambers out there and a few different styles, I do favor the SBP one obviously

Last edited by BarelyAWake : 11-05-2009 at 01:30 PM.
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Old 11-05-2009, 02:37 PM
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Talking Re: custom exhaust

Quote:
Originally Posted by BarelyAWake View Post
Most exhaust is mild steel stock, I'm sorry but I've no idea the wall thickness - me and numbers lol However - mild steel of that size is fairly simple to bend yourself. Any two points of contact and leverage will do it, best if you can find a round surface - but just about anything will do. People 'round here have used conduit with success - I've just not messed w/it myself.

Lotsa lil bends to make a big or sharp bend, that's all there really is to it if you haven't a proper tubing bender. If yer going with stainless tho it's another matter - that stuff is rugged and somewhat brittle/prone to cracking from bending abuse. I personally think stainless is great - but maybe not worth it for the do-it-yerself... maybe not for this application either - I'd just make another if I needed to. It's all up to the builder tho

I'd still go with a tuned exhaust, even a custom job - over a regular pipe & can. It's just too much a response to overlook - the 2 stroke begs for 'em lol

The two springs on the SBP's pipe are because it's a flexible joint. Common to see on other "small" 2 stroke vehicles like snowmobiles and ultralights, it helps reduce metal fatigue due to vibration and torque flex. It is usually a ball & socket joint, the SBP's one also gives more options for mounting orientation.

There's a buncha sweet expansion chambers out there and a few different styles, I do favor the SBP one obviously
Thanks for the info barelyawake, it helped me out alot

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Old 11-06-2009, 02:17 PM
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Default Re: custom exhaust

1/2" and 3/4" EMT (steel electrical conduit) works great. Benders are cheap and once you get the knack of getting the bend where you want it you can do almost anything as far as an exhaust system goes. The bend radius is a little longer than I'd like but with some practice you can reduce the radius by moving the pipe in the bender as you go. There's no need for sand or heat. An added plus is if you use new conduit the galvanized coating will take a nice shine with a little work on the buffing wheel and some compound. Napa sells a silver high temp engine rattle can paint that will withstand the exhaust heat even right at the cylinder/flange.
Here's a couple of pipes to give you an idea of what's possible.
Tom
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custom-exhaust-jag-finished-1.jpg  custom-exhaust-ready-paint-5.jpg  
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Old 11-06-2009, 03:17 PM
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Talking Re: custom exhaust

Quote:
Originally Posted by 2door View Post
1/2" and 3/4" EMT (steel electrical conduit) works great. Benders are cheap and once you get the knack of getting the bend where you want it you can do almost anything as far as an exhaust system goes. The bend radius is a little longer than I'd like but with some practice you can reduce the radius by moving the pipe in the bender as you go. There's no need for sand or heat. An added plus is if you use new conduit the galvanized coating will take a nice shine with a little work on the buffing wheel and some compound. Napa sells a silver high temp engine rattle can paint that will withstand the exhaust heat even right at the cylinder/flange.
Here's a couple of pipes to give you an idea of what's possible.
Tom
hey thanks 2Door, Do u ow if they carry that high temp paint in a flat or satin blk?


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