Need help on modding exhaust to fit.

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Ballin on a Budget

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May 26, 2011
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Im sure everyone that has built one of these kits knows that (unless you have a v-frame bike from 1987 w/1" tubing adn enough clearance for a v-twin) it involves a fair amount of problem solving.....here's my first.

Im using the exhaust that came with my chinese 66cc kit and it seems to be the newer style. In order to clear the downtube and sit flush on the cylinder, it will need some mods. Ive read lots of posts and everyone just says bend it, which I tried. But I dunno if they changed the pipe material or something but its REALLY strong and will not bend with any ease. My soloutions are this
1 - extend the pipe out 2 or so inches, or......
2 - cut off the flange and flip it so its upside down and re-attach it.

The second option seems to be the best and easiest fix but I dont have a welder and I need to know the easiest way to re-attach the flange to the rest of the pipe without welding....any ideas would be massively appreciated....(the pis show the angle at the cylinder im talking about and what type of muffler it is.

Thanks
 

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Mike B

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Mar 23, 2011
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The pipe is a good fit for 3/4" copper couplers, so you can buy 1 and a couple of hose clamps, cut slits in the coupler and the clamps will work.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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in order to bend it easily, you need a propane torch (or a MAPP gas one is hotter) that you can get from a hardware store for under 20 bucks, a sturdy vice or somewhere you can wedge the pipe into, and a 4' pipe that fits over the exhaust.

heat up the area where you want the bend, then using the long pipe as a lever, it'll bend like butter.

ever since they started welding the flanges on an angle they got more difficult to bend. i mean, they'll still bend easy, but you gotta mess with it more. some pipes had the flange welded on flat, and those were easy.
 

Ballin on a Budget

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May 26, 2011
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Awesome......Thanks for the prompt reply guys! Since I dont have a torch ( or a vice where im workin) the copper pipe idea sounds perfect for what i need. Plus it may be a lil better flow wise as cant bending it sometimes narrow the pipe in the bend? Prob wouldnt be a noticable difference tho. Im gonna heat wrap the pipe anyways for a cleaner look after i splice it so copper pipe and clamps should work out fine. Thanks again
-Dan
 

DuctTapedGoat

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Dec 20, 2010
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Nampa Idaho
I gotta say it - don't bend it while it's attached to the motor, and if you're not using a vice, it's probably not going to bend.

Bairdco has it nailed, heat it up and bend it - that's going to be the easiest and safest way.

Granted, I usually do it the not as easy way and just vice it below the flange and bend it with a long screwdriver down the stinger, but every time I do that I do risk taking out a weld, or tearing/folding the pipe. Not saying it's 100% bound to happen, but it's not 0%.
 

Mike B

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Mar 23, 2011
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Yeah the 3/4" copper works good.

Here's mine, a coupler a piece of water heater flex pipe and a 45 degree elbow.



I just cut the muffler pipe off between the flange and the body.
 

LS614

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Dec 22, 2009
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Today at my "problem solving buddy's" place I beheld the power of an acetylene torch. If you have not already done something to your pipe, you should find a local with an acetylene torch (shouldn't be that hard) and pay a few bucks to have them help you heat it, yes while it is on the engine, and bend it. The acetylene torch will heat it to red in a matter of SECONDS as opposed to propane which takes a LONG time. Just have them heat it and then push and bend as needed. If the wielder of the torch is skilled they will not harm your paint, my buddy was heating my exhaust right next to my duct tape "paint job" and didn't even burn or melt the tape :)
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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sorry, LS614, but i have to disagree with your method, even though it worked for you, and here's why;

the threads and studs on the jug could easily be damaged or destroyed if too much pressure is applied. they fail enough on their own as it is, and to use them as a leverage point is just asking for trouble.

it's simple enough to mark where the bend needs to be, remove the pipe and bend it, then re-check, re-do, etc till it's right.

another thing, which could be much worse than stripped threads or broken studs, is the possibility of torching your whole bike.

a drip of gas, some oily residue, fumes coming out of the filter, or a careless mistake could make your whole bike go up in flames. not to mention everything around it, including you.

as i said, it worked for you, and that's good, but it's definitely not something to recommend to the average joe...
 

LS614

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Dec 22, 2009
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I agree with ya Baird. For my application we were just changing the direction of the silencer part of the sbp expansion chamber, and he had already added a second sturdy welded mount in addition to the studs on the engine. After I wrote this I thought more about it, and if ya wanna be safe and do it right you totally should take it off the bike :)
 

Ballin on a Budget

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May 26, 2011
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Vernon, British Columbia
That water heater pipe is a great idea! I knew what it was and I just couldnt remeber its application so I could fins some...but now that you sparked my memory, you can get it at electrical suppliers as well as it is used as conduit pipe sometimes. I solved my problem by cutting and spliccing my pipe with a steel couple that i cut a slot in and clamped....it worked pretty well, but im gonna want to eventually extend the pipe a bit cuz these pipes are really short, so I may use the flexible pipe when i do so.
-Dan
 

dmb

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Dec 4, 2010
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lakewood ca
a old pipe benders trick to avoid crimps. fill the pipe with sand. a cheep way to remove a dent from a tank. fill with water put the cap on and freeze it, keep an eye on it because you can split the tank. use to fix dents on the old down pipe MX'rs that way